Curr Opin Microbiol. 2009 Jul 3. [Epub ahead of print]
Mechanisms controlling glideosome function in apicomplexans
Daher W, Soldati-Favre D.
Department of Microbiology and Molecular Medicine, CMU, University of Geneva, 1 rue Michel-Servet, 1211 Geneva 4, Switzerland.
The glideosome is a unique attribute of the Apicomplexa phylum. This myosin-based machine powers parasite motility, migration across biological barriers, host cell invasion and egress from infected cells. The timing, duration and orientation of gliding motility are tightly regulated to assure establishment of infection. Control of glideosome function occurs at several levels. The assembly of the molecular motor complex is governed by posttranslational modifications resulting from a calcium-dependent signalling cascade. The spatially controlled polymerization of actin filaments crucially impacts motility. The relocation of glycolytic enzymes in close proximity of the glideosome may enhance the local production of energy to sustain movement.
PMID: 19577950 [PubMed - as supplied by publisher]
Wednesday, July 08, 2009
Comparison of effects of green tea catechins on apicomplexan hexose transporters and mammalian orthologues
Mol Biochem Parasitol. 2009 Jul 2. [Epub ahead of print]
Comparison of effects of green tea catechins on apicomplexan hexose transporters and mammalian orthologues
Slavic K, Derbyshire ET, Naftalin RJ, Krishna S, Staines HM.
Centre for Infection, Division of Cellular and Molecular Medicine, St. George's, University of London, Cranmer Terrace, London SW17 0RE, UK.
Here we have investigated the inhibitory properties of green tea catechins on the Plasmodium falciparum hexose transporter (PfHT), the Babesia bovis hexose transporter 1 (BboHT1) and the mammalian facilitative glucose transporters, GLUT1 and GLUT5, expressed in Xenopus laevis oocytes. (-)-Epicatechin-gallate (ECG) and (-)-epigallocatechin-gallate (EGCG) inhibited D-glucose transport by GLUT1 and PfHT, and D-fructose transport by GLUT5, with apparent K(i) values between 45 and 117muM. BboHT1 was more potently inhibited by the ungallated catechins (-)-epicatechin (EC) and (-)-epigallocatechin (EGC), with apparent K(i) values of 108 and 168muM, respectively. Site-directed mutagenesis experiments provided little further support for previously reported models of catechin binding to hexose transporters. Furthermore, P. falciparum growth inhibition by catechins was not affected by the external D-glucose concentration. Our results provide new data on the inhibitory action of catechins against sugar transporters but were unable to elucidate the antimalarial mechanism of action of these agents.
PMID: 19577593 [PubMed - as supplied by publisher]
Comparison of effects of green tea catechins on apicomplexan hexose transporters and mammalian orthologues
Slavic K, Derbyshire ET, Naftalin RJ, Krishna S, Staines HM.
Centre for Infection, Division of Cellular and Molecular Medicine, St. George's, University of London, Cranmer Terrace, London SW17 0RE, UK.
Here we have investigated the inhibitory properties of green tea catechins on the Plasmodium falciparum hexose transporter (PfHT), the Babesia bovis hexose transporter 1 (BboHT1) and the mammalian facilitative glucose transporters, GLUT1 and GLUT5, expressed in Xenopus laevis oocytes. (-)-Epicatechin-gallate (ECG) and (-)-epigallocatechin-gallate (EGCG) inhibited D-glucose transport by GLUT1 and PfHT, and D-fructose transport by GLUT5, with apparent K(i) values between 45 and 117muM. BboHT1 was more potently inhibited by the ungallated catechins (-)-epicatechin (EC) and (-)-epigallocatechin (EGC), with apparent K(i) values of 108 and 168muM, respectively. Site-directed mutagenesis experiments provided little further support for previously reported models of catechin binding to hexose transporters. Furthermore, P. falciparum growth inhibition by catechins was not affected by the external D-glucose concentration. Our results provide new data on the inhibitory action of catechins against sugar transporters but were unable to elucidate the antimalarial mechanism of action of these agents.
PMID: 19577593 [PubMed - as supplied by publisher]
Dynamic Imaging of CD8(+) T cells and dendritic cells during infection with Toxoplasma
PLoS Pathog. 2009 Jul;5(7):e1000505. Epub 2009 Jul 3
Dynamic Imaging of CD8(+) T cells and dendritic cells during infection with Toxoplasma gondii
John B, Harris TH, Tait ED, Wilson EH, Gregg B, Ng LG, Mrass P, Roos DS, Dzierszinski F, Weninger W, Hunter CA.
Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA.
To better understand the initiation of CD8(+) T cell responses during infection, the primary response to the intracellular parasite Toxoplasma gondii was characterized using 2-photon microscopy combined with an experimental system that allowed visualization of dendritic cells (DCs) and parasite specific CD8(+) T cells. Infection with T. gondii induced localization of both these populations to the sub-capsular/interfollicular region of the draining lymph node and DCs were required for the expansion of the T cells. Consistent with current models, in the presence of cognate antigen, the average velocity of CD8(+) T cells decreased. Unexpectedly, infection also resulted in modulation of the behavior of non-parasite specific T cells. This TCR-independent process correlated with the re-modeling of the lymph node micro-architecture and changes in expression of CCL21 and CCL3. Infection also resulted in sustained interactions between the DCs and CD8(+) T cells that were visualized only in the presence of cognate antigen and were limited to an early phase in the response. Infected DCs were rare within the lymph node during this time frame; however, DCs presenting the cognate antigen were detected. Together, these data provide novel insights into the earliest interaction between DCs and CD8(+) T cells and suggest that cross presentation by bystander DCs rather than infected DCs is an important route of antigen presentation during toxoplasmosis.
Publication Types:
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
PMID: 19578440 [PubMed - in process]
Dynamic Imaging of CD8(+) T cells and dendritic cells during infection with Toxoplasma gondii
John B, Harris TH, Tait ED, Wilson EH, Gregg B, Ng LG, Mrass P, Roos DS, Dzierszinski F, Weninger W, Hunter CA.
Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA.
To better understand the initiation of CD8(+) T cell responses during infection, the primary response to the intracellular parasite Toxoplasma gondii was characterized using 2-photon microscopy combined with an experimental system that allowed visualization of dendritic cells (DCs) and parasite specific CD8(+) T cells. Infection with T. gondii induced localization of both these populations to the sub-capsular/interfollicular region of the draining lymph node and DCs were required for the expansion of the T cells. Consistent with current models, in the presence of cognate antigen, the average velocity of CD8(+) T cells decreased. Unexpectedly, infection also resulted in modulation of the behavior of non-parasite specific T cells. This TCR-independent process correlated with the re-modeling of the lymph node micro-architecture and changes in expression of CCL21 and CCL3. Infection also resulted in sustained interactions between the DCs and CD8(+) T cells that were visualized only in the presence of cognate antigen and were limited to an early phase in the response. Infected DCs were rare within the lymph node during this time frame; however, DCs presenting the cognate antigen were detected. Together, these data provide novel insights into the earliest interaction between DCs and CD8(+) T cells and suggest that cross presentation by bystander DCs rather than infected DCs is an important route of antigen presentation during toxoplasmosis.
Publication Types:
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
PMID: 19578440 [PubMed - in process]
Transmembrane domain containing surface protein from Toxoplasma augments replication in activated immune cells and est of chronic infection
Infect Immun. 2009 Jul 6. [Epub ahead of print]
Transmembrane domain containing surface protein from Toxoplasma gondii augments replication in activated immune cells and the establishment of a chronic infection
Pollard AM, Skariah S, Mordue DG, Knoll LJ.
Toxoplasma gondii mutants identified as defective in the establishment of chronic infection were screened to isolate those specifically impaired in their ability to replicate within activated macrophages. One of the identified mutants contains an insertion in hypothetical gene TGME49_111670. Genetic complementation restores the ability of the mutant to replicate in immune cells and produce cysts in the brains of mice. While the mutant is more sensitive to nitric oxide compared to its parental strain, it is not defective in its ability to suppress nitric oxide. The disrupted protein has no significant homology to proteins with known functions, but is predicted to have one transmembrane domain. Immunofluorescence shows the protein on the parasite surface even in activated macrophages, co-localizing with a tachyzoite surface antigen SAG1, and oriented with its C-terminal end external. Western analysis reveals that the protein is down regulated in bradyzoites. Despite the tachyzoite-specificity of this protein, mice infected with the mutant succumb to acute infection similarly to those infected with the parent strain. Serum from mice with a chronic T. gondii infection reacts to a polypeptide from TGME49_11670, indicating that the protein is seen by the immune system during infection. This study is the first to characterize a T. gondii surface protein that contains a transmembrane domain, and show that the protein contributes to parasite replication in activated immune cells and the establishment of chronic infection.
PMID: 19581395 [PubMed - as supplied by publisher]
Transmembrane domain containing surface protein from Toxoplasma gondii augments replication in activated immune cells and the establishment of a chronic infection
Pollard AM, Skariah S, Mordue DG, Knoll LJ.
Toxoplasma gondii mutants identified as defective in the establishment of chronic infection were screened to isolate those specifically impaired in their ability to replicate within activated macrophages. One of the identified mutants contains an insertion in hypothetical gene TGME49_111670. Genetic complementation restores the ability of the mutant to replicate in immune cells and produce cysts in the brains of mice. While the mutant is more sensitive to nitric oxide compared to its parental strain, it is not defective in its ability to suppress nitric oxide. The disrupted protein has no significant homology to proteins with known functions, but is predicted to have one transmembrane domain. Immunofluorescence shows the protein on the parasite surface even in activated macrophages, co-localizing with a tachyzoite surface antigen SAG1, and oriented with its C-terminal end external. Western analysis reveals that the protein is down regulated in bradyzoites. Despite the tachyzoite-specificity of this protein, mice infected with the mutant succumb to acute infection similarly to those infected with the parent strain. Serum from mice with a chronic T. gondii infection reacts to a polypeptide from TGME49_11670, indicating that the protein is seen by the immune system during infection. This study is the first to characterize a T. gondii surface protein that contains a transmembrane domain, and show that the protein contributes to parasite replication in activated immune cells and the establishment of chronic infection.
PMID: 19581395 [PubMed - as supplied by publisher]
Vertical transmission of HIV and toxoplasma by reactivation in a chronically infected woman
Braz J Infect Dis. 2009 Feb;13(1):70-1
Vertical transmission of HIV and toxoplasma by reactivation in a chronically infected woman
Fernandes RC, Vasconcellos VP, Araújo LC, Medina-Acosta E.
Municipal Program for the Surveillance of Sexually Transmitted Diseases and AIDS, Campos dos Goytacazes, Brazil. reg.fernandes@bol.com.br
Prevention of mother-to-child transmission of HIV and Toxoplasma dual infections in the immunocompromised patient remains a healthcare challenge. We report a case of congenital toxoplasmosis resulting from reactivation of latent infection in a severely immunodepressed HIV-infected pregnant woman, who had poor adherence to therapy; this case illustrates the difficulties encountered in management of such a rare condition.
Publication Types:
Research Support, Non-U.S. Gov't
PMID: 19578634 [PubMed - in process]
Vertical transmission of HIV and toxoplasma by reactivation in a chronically infected woman
Fernandes RC, Vasconcellos VP, Araújo LC, Medina-Acosta E.
Municipal Program for the Surveillance of Sexually Transmitted Diseases and AIDS, Campos dos Goytacazes, Brazil. reg.fernandes@bol.com.br
Prevention of mother-to-child transmission of HIV and Toxoplasma dual infections in the immunocompromised patient remains a healthcare challenge. We report a case of congenital toxoplasmosis resulting from reactivation of latent infection in a severely immunodepressed HIV-infected pregnant woman, who had poor adherence to therapy; this case illustrates the difficulties encountered in management of such a rare condition.
Publication Types:
Research Support, Non-U.S. Gov't
PMID: 19578634 [PubMed - in process]
Thursday, July 02, 2009
Post-doctoral position available
A post-doctoral position is available in the laboratory of Silvia Moreno (smoreno@cb.uga.edu) at the Center for Tropical and Emerging Global Diseases, University of Georgia, to study the role of a recently discovered plant-like vacuole from Toxoplasma gondii. This new organelle contains several important transporters usually found in the tonoplast (the membrane of the plant vacuole), such as the vacuolar-proton pyrophosphatase, an aquaporin channel and a cysteine protease similar to aleurain, a plant vacuole protease. Proteomic analysis of a subcellular fraction enriched in this organelle indicates that it contains several transporters and enzymes involved in the homeostasis of calcium and other ions. Preliminary results from our laboratory indicate a
homeostatic role during the survival of the parasite while outside the host cell.
The project will study:
1) The role of the plant-like vacuole in the homeostasis of calcium and other ions in Toxoplasma gondii.
2) Trafficking of proteins to and from this organelle and its relationship with the endocytic pathway
3) Biogenesis and fusion of the plant-like vacuole with other vacuoles such as acidocalcisomes
The laboratory interacts very closely with the laboratory of Dr. Roberto Docampo with several areas of research in common as ion metabolism and cell signaling of Toxoplasma gondii and trypanosomatids (Trypanosoma cruzi, T. brucei and Leishmania spp.). Since the first description of the acidocalcisomes in Trypanosoma brucei we have been studying their function and origin. As the characteristics and features of acidocalcisomes were revealed, it became apparent that they were morphologically and chemically similar to the “granules” described more than 100 years ago as “metachromatic granules”, “volutin granules” or “polyphosphate bodies” in different microorganisms. For more information on our group research interests check our web site: http://docampo_moreno.ctegd.uga.edu/.
Applicants should have a PhD in a biological science field. Preference will be given to applicants with strong background in molecular biology and/or cell biology. Experience working with Toxoplasma gondii is not necessary but is an advantage.
Interested candidates should contact Dr. Silvia N.J. Moreno by email: smoreno@cb.uga.edu and send their CV and the names/emails of three references.
Evaluation of Toxoplasma gondii placental transmission in BALB/c mice model
Exp Parasitol. 2009 Jun 26. [Epub ahead of print]
Evaluation of Toxoplasma gondii placental transmission in BALB/c mice model
Pezerico SB, Langoni H, Silva AV, Silva RC.
Faculdade de Medicina de Botucatu (FMB), Universidade Estadual Paulista (UNESP), 18618-000, Botucatu, SP, Brazil; Faculdade de Medicina Veterinária e Zootecnia(FMVZ), Universidade Estadual Paulista (UNESP), 18618-000, Botucatu, SP, Brazil.
Toxoplasma gondii infection is common worldwide and highly important to pregnant women as it can be transmitted to the fetus via the placenta. This study aimed at evaluating the prevention of placental transmission in two different strains after chronic infection with each one of the strains. A BALB/c mice model was inoculated 30 days before breeding (immunization) and re-infected 12 and 15 days after pregnancy (challenge). Seven experimental groups were assayed: G1: ME49-immunization (type II), M7741-challenge (type III); G2: M7741-immunization, ME49-challenge; G3, ME49-immunization; G4: M7741-immunization; G5: ME49-challenge; G6: M7741-challenge; G7: saline solution inoculation. Serology, mouse bioassay, PCR and RLFP of the uterus, placenta and fetus were performed to determine the congenital transmission of the strains challenged after chronic infection. IgG T. gondii antibodies were detected in G1, G2, G3 and G4, but not in G5, G6 and G7. All animals of G5 and G6 were IgM-positive. Congenital infection was not detected by bioassay and PCR. Nonetheless, placentas from G3 and G4 resulted positive but no corresponding fetal infection was detected. G1 and G2 did not show the genotype of the strain challenged during pregnancy, only those of chronic infection. Thus, the chronically infected BALB/c mice showed no re-infection after inoculation with another strain during pregnancy. Further studies with different parasite loads and different mice lineages are needed.
PMID: 19563804 [PubMed - as supplied by publisher]
Evaluation of Toxoplasma gondii placental transmission in BALB/c mice model
Pezerico SB, Langoni H, Silva AV, Silva RC.
Faculdade de Medicina de Botucatu (FMB), Universidade Estadual Paulista (UNESP), 18618-000, Botucatu, SP, Brazil; Faculdade de Medicina Veterinária e Zootecnia(FMVZ), Universidade Estadual Paulista (UNESP), 18618-000, Botucatu, SP, Brazil.
Toxoplasma gondii infection is common worldwide and highly important to pregnant women as it can be transmitted to the fetus via the placenta. This study aimed at evaluating the prevention of placental transmission in two different strains after chronic infection with each one of the strains. A BALB/c mice model was inoculated 30 days before breeding (immunization) and re-infected 12 and 15 days after pregnancy (challenge). Seven experimental groups were assayed: G1: ME49-immunization (type II), M7741-challenge (type III); G2: M7741-immunization, ME49-challenge; G3, ME49-immunization; G4: M7741-immunization; G5: ME49-challenge; G6: M7741-challenge; G7: saline solution inoculation. Serology, mouse bioassay, PCR and RLFP of the uterus, placenta and fetus were performed to determine the congenital transmission of the strains challenged after chronic infection. IgG T. gondii antibodies were detected in G1, G2, G3 and G4, but not in G5, G6 and G7. All animals of G5 and G6 were IgM-positive. Congenital infection was not detected by bioassay and PCR. Nonetheless, placentas from G3 and G4 resulted positive but no corresponding fetal infection was detected. G1 and G2 did not show the genotype of the strain challenged during pregnancy, only those of chronic infection. Thus, the chronically infected BALB/c mice showed no re-infection after inoculation with another strain during pregnancy. Further studies with different parasite loads and different mice lineages are needed.
PMID: 19563804 [PubMed - as supplied by publisher]
A Toxoplasma type 2C serine-threonine phosphatase is involved in parasite growth in the mammalian host cell
Microbes Infect. 2009 Jun 26. [Epub ahead of print]
A Toxoplasma type 2C serine-threonine phosphatase is involved in parasite growth in the mammalian host cell
Jan G, Delorme V, Saksouk N, Abrivard M, Gonzalez V, Cayla X, Hakimi MA, Tardieux I.
Institut Cochin, Université Paris Descartes, CNRS UMR 8104, Paris, France; Inserm, U567, Paris, France.
Toxoplasma gondii is a human protozoan parasite that belongs to the phylum of Apicomplexa and causes toxoplasmosis. As the other members of this phylum, T. gondii obligatory multiplies within a host cell by a peculiar type of mitosis that leads to daughter cell assembly within a mother cell. Although parasite growth and virulence have been linked for years, few molecules controlling mitosis have been yet identified and they include a couple of kinases but not the counteracting phosphatases. Here, we report that in contrast to other animal cells, type 2C is by far the major type of serine threonine phosphatase activity both in extracellular and in intracellular dividing parasites. Using wild type and transgenic parasites, we characterized the 37kDa TgPP2C molecule as an abundant cytoplasmic and nuclear enzyme with activity being under tight regulation. In addition, we showed that the increase in TgPP2C activity significantly affected parasite growth by impairing cytokinesis while nuclear division still occurred. This study supports for the first time that type 2C protein phosphatase is an important regulator of cell growth in T. gondii.
PMID: 19563907 [PubMed - as supplied by publisher]
A Toxoplasma type 2C serine-threonine phosphatase is involved in parasite growth in the mammalian host cell
Jan G, Delorme V, Saksouk N, Abrivard M, Gonzalez V, Cayla X, Hakimi MA, Tardieux I.
Institut Cochin, Université Paris Descartes, CNRS UMR 8104, Paris, France; Inserm, U567, Paris, France.
Toxoplasma gondii is a human protozoan parasite that belongs to the phylum of Apicomplexa and causes toxoplasmosis. As the other members of this phylum, T. gondii obligatory multiplies within a host cell by a peculiar type of mitosis that leads to daughter cell assembly within a mother cell. Although parasite growth and virulence have been linked for years, few molecules controlling mitosis have been yet identified and they include a couple of kinases but not the counteracting phosphatases. Here, we report that in contrast to other animal cells, type 2C is by far the major type of serine threonine phosphatase activity both in extracellular and in intracellular dividing parasites. Using wild type and transgenic parasites, we characterized the 37kDa TgPP2C molecule as an abundant cytoplasmic and nuclear enzyme with activity being under tight regulation. In addition, we showed that the increase in TgPP2C activity significantly affected parasite growth by impairing cytokinesis while nuclear division still occurred. This study supports for the first time that type 2C protein phosphatase is an important regulator of cell growth in T. gondii.
PMID: 19563907 [PubMed - as supplied by publisher]
Toxoplasma gondii cyclophilin 18-mediated production of nitric oxide induces bradyzoite conversion in a CCR5-dependent manner
Infect Immun. 2009 Jun 29. [Epub ahead of print]
Toxoplasma gondii cyclophilin 18-mediated production of nitric oxide induces bradyzoite conversion in a CCR5-dependent manner
Ibrahim HM, Bannai H, Xuan X, Nishikawa Y.
National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan; Zoology Department, Faculty of Science, Minufiya University, Shibin El kom, Egypt.
Toxoplasma gondii modulates pro- and anti-inflammatory responses to regulate parasite multiplication and host survival. Pressure from the immune response causes the conversion of tachyzoites to slowly dividing bradyzoites. The regulatory mechanisms involved in this switch are poorly understood. The aim of this study was to investigate the immunomodulatory role of T. gondii cyclophilin18 (TgCyp18) in macrophages and the consequences of the cellular responses on the conversion machinery. The recombinant TgCyp18 induced the production of nitric oxide (NO), IL-12 and TNF-alpha through its binding with cysteine-cysteine chemokine receptor 5 (CCR5) and the production of IFN-gamma and IL-6 in a CCR5-independent manner. Interestingly, treatment of macrophages with TgCyp18 resulted in the inhibition of parasite growth and enhancement of the conversion into bradyzoites via NO in a CCR5-dependent manner. In conclusion, T. gondii possesses sophisticated mechanisms to manipulate host-cell responses in a TgCyp18-mediated process.
PMID: 19564392 [PubMed - as supplied by publisher]
Toxoplasma gondii cyclophilin 18-mediated production of nitric oxide induces bradyzoite conversion in a CCR5-dependent manner
Ibrahim HM, Bannai H, Xuan X, Nishikawa Y.
National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan; Zoology Department, Faculty of Science, Minufiya University, Shibin El kom, Egypt.
Toxoplasma gondii modulates pro- and anti-inflammatory responses to regulate parasite multiplication and host survival. Pressure from the immune response causes the conversion of tachyzoites to slowly dividing bradyzoites. The regulatory mechanisms involved in this switch are poorly understood. The aim of this study was to investigate the immunomodulatory role of T. gondii cyclophilin18 (TgCyp18) in macrophages and the consequences of the cellular responses on the conversion machinery. The recombinant TgCyp18 induced the production of nitric oxide (NO), IL-12 and TNF-alpha through its binding with cysteine-cysteine chemokine receptor 5 (CCR5) and the production of IFN-gamma and IL-6 in a CCR5-independent manner. Interestingly, treatment of macrophages with TgCyp18 resulted in the inhibition of parasite growth and enhancement of the conversion into bradyzoites via NO in a CCR5-dependent manner. In conclusion, T. gondii possesses sophisticated mechanisms to manipulate host-cell responses in a TgCyp18-mediated process.
PMID: 19564392 [PubMed - as supplied by publisher]
Is Toxoplasma gondii a Causal Agent in Migraine?
Am J Med Sci. 2009 Jun 26. [Epub ahead of print]
Is Toxoplasma gondii a Causal Agent in Migraine?
Koseoglu E, Yazar S, Koc I.
From the Departments of Neurology (ek, ik) and Parasitology (sy), Medical Faculty, Erciyes University, Kayseri, Turkey.
BACKGROUND:: Many different tissues may be parasitized by Toxoplasma gondii, particularly, lung, heart, lymphoid organs, and the central nervous tissues. Tissue cysts of this parasite in the brain may spontaneously rupture, releasing parasites that cause antibody titers to rise. In immunocompetent subjects with acquired toxoplasmosis, the most frequent symptoms were lymphadenopathy and headache. In the neurogenic inflammation theory of the pathogenesis of migraine, the cause of initial release of ions and inflammatory agents has not been established. In this study, we aimed to investigate if T. gondii infection is a possible cause of neurogenic inflammation of migraines. METHODS:: The anti-T. gondii antibody status of 104 patients with migraine were studied and compared with those of control groups, 50 healthy subjects and 50 subjects with headache due to rhinosinusitis, by using a micro-enzyme-linked immunosorbent assay technique. RESULTS:: Forty-six (44.2%) patients with migraine, 13 (26.0%) healthy control subjects, and 12 (24%) control subjects with rhinosinusitis were positive for anti-T. gondii IgG antibody. The rate of positivity in the migraine patient group was statistically different from those of the control groups (P < 0.05). CONCLUSIONS:: The results show the presence of chronic Toxoplasma infection in patients with migraine. Toxoplasma infection may contribute to neurogenic inflammation as the pathogenesis of migraine, as many studies in the literature have reported that Toxoplasma infection causes biochemical and immunologic changes.
PMID: 19564786 [PubMed - as supplied by publisher]
Is Toxoplasma gondii a Causal Agent in Migraine?
Koseoglu E, Yazar S, Koc I.
From the Departments of Neurology (ek, ik) and Parasitology (sy), Medical Faculty, Erciyes University, Kayseri, Turkey.
BACKGROUND:: Many different tissues may be parasitized by Toxoplasma gondii, particularly, lung, heart, lymphoid organs, and the central nervous tissues. Tissue cysts of this parasite in the brain may spontaneously rupture, releasing parasites that cause antibody titers to rise. In immunocompetent subjects with acquired toxoplasmosis, the most frequent symptoms were lymphadenopathy and headache. In the neurogenic inflammation theory of the pathogenesis of migraine, the cause of initial release of ions and inflammatory agents has not been established. In this study, we aimed to investigate if T. gondii infection is a possible cause of neurogenic inflammation of migraines. METHODS:: The anti-T. gondii antibody status of 104 patients with migraine were studied and compared with those of control groups, 50 healthy subjects and 50 subjects with headache due to rhinosinusitis, by using a micro-enzyme-linked immunosorbent assay technique. RESULTS:: Forty-six (44.2%) patients with migraine, 13 (26.0%) healthy control subjects, and 12 (24%) control subjects with rhinosinusitis were positive for anti-T. gondii IgG antibody. The rate of positivity in the migraine patient group was statistically different from those of the control groups (P < 0.05). CONCLUSIONS:: The results show the presence of chronic Toxoplasma infection in patients with migraine. Toxoplasma infection may contribute to neurogenic inflammation as the pathogenesis of migraine, as many studies in the literature have reported that Toxoplasma infection causes biochemical and immunologic changes.
PMID: 19564786 [PubMed - as supplied by publisher]
Tuesday, June 30, 2009
Emerging food-borne parasites
Vet Parasitol. 2009 Jun 6. [Epub ahead of print]
Emerging food-borne parasites
Dorny P, Praet N, Deckers N, Gabriel S.
Department of Animal Health, Institute of Tropical Medicine, 155 Nationalestraat, B-2000 Antwerp, Belgium.
Parasitic food-borne diseases are generally underrecognised, however they are becoming more common. Globalization of the food supply, increased international travel, increase of the population of highly susceptible persons, change in culinary habits, but also improved diagnostic tools and communication are some factors associated with the increased diagnosis of food-borne parasitic diseases worldwide. This paper reviews the most important emerging food-borne parasites, with emphasis on transmission routes. In a first part, waterborne parasites transmitted by contaminated food such as Cyclospora cayetanensis, Cryptosporidium and Giardia are discussed. Also human fasciolosis, of which the importance has only been recognised in the last decades, with total numbers of reported cases increasing from less than 3000 to 17 million, is looked at. Furthermore, fasciolopsiosis, an intestinal trematode of humans and pigs belongs to the waterborne parasites as well. A few parasites that may be transmitted through faecal contamination of foods and that have received renewed attention, such as Toxoplasma gondii, or that are (re-)emerging, such as Trypanosoma cruzi and Echinococcus spp., are briefly reviewed. In a second part, meat-borne parasite infections are reviewed. Humans get infected by eating raw or undercooked meat infected with cyst stages of these parasites. Meat inspection is the principal method applied in the control of Taenia spp. and Trichinella spp. However, it is often not very sensitive, frequently not practised, and not done for T. gondii and Sarcocystis spp. Meat of reptiles, amphibians and fish can be infected with a variety of parasites, including trematodes (Opisthorchis spp., Clonorchis sinensis, minute intestinal flukes), cestodes (Diphyllobothrium spp., Spirometra), nematodes (Gnathostoma, spp., anisakine parasites), and pentastomids that can cause zoonotic infections in humans when consumed raw or not properly cooked. Another important zoonotic food-borne trematode is the lungfluke (Paragonimus spp.). Traditionally, these parasitic zoonoses are most common in Asia because of the particular food practices and the importance of aquaculture. However, some of these parasites may emerge in other continents through aquaculture and improved transportation and distribution systems. Because of inadequate systems for routine diagnosis and monitoring or reporting for many of the zoonotic parasites, the incidence of human disease and parasite occurrence in food is underestimated. Of particular concern in industrialised countries are the highly resistant waterborne protozoal infections as well as the increased travel and immigration, which increase the exposure to exotic diseases. The increased demand for animal proteins in developing countries will lead to an intensification of the production systems in which the risk of zoonotic infections needs to be assessed. Overall, there is an urgent need for better monitoring and control of food-borne parasites using new technologies.
PMID: 19559535 [PubMed - as supplied by publisher]
Emerging food-borne parasites
Dorny P, Praet N, Deckers N, Gabriel S.
Department of Animal Health, Institute of Tropical Medicine, 155 Nationalestraat, B-2000 Antwerp, Belgium.
Parasitic food-borne diseases are generally underrecognised, however they are becoming more common. Globalization of the food supply, increased international travel, increase of the population of highly susceptible persons, change in culinary habits, but also improved diagnostic tools and communication are some factors associated with the increased diagnosis of food-borne parasitic diseases worldwide. This paper reviews the most important emerging food-borne parasites, with emphasis on transmission routes. In a first part, waterborne parasites transmitted by contaminated food such as Cyclospora cayetanensis, Cryptosporidium and Giardia are discussed. Also human fasciolosis, of which the importance has only been recognised in the last decades, with total numbers of reported cases increasing from less than 3000 to 17 million, is looked at. Furthermore, fasciolopsiosis, an intestinal trematode of humans and pigs belongs to the waterborne parasites as well. A few parasites that may be transmitted through faecal contamination of foods and that have received renewed attention, such as Toxoplasma gondii, or that are (re-)emerging, such as Trypanosoma cruzi and Echinococcus spp., are briefly reviewed. In a second part, meat-borne parasite infections are reviewed. Humans get infected by eating raw or undercooked meat infected with cyst stages of these parasites. Meat inspection is the principal method applied in the control of Taenia spp. and Trichinella spp. However, it is often not very sensitive, frequently not practised, and not done for T. gondii and Sarcocystis spp. Meat of reptiles, amphibians and fish can be infected with a variety of parasites, including trematodes (Opisthorchis spp., Clonorchis sinensis, minute intestinal flukes), cestodes (Diphyllobothrium spp., Spirometra), nematodes (Gnathostoma, spp., anisakine parasites), and pentastomids that can cause zoonotic infections in humans when consumed raw or not properly cooked. Another important zoonotic food-borne trematode is the lungfluke (Paragonimus spp.). Traditionally, these parasitic zoonoses are most common in Asia because of the particular food practices and the importance of aquaculture. However, some of these parasites may emerge in other continents through aquaculture and improved transportation and distribution systems. Because of inadequate systems for routine diagnosis and monitoring or reporting for many of the zoonotic parasites, the incidence of human disease and parasite occurrence in food is underestimated. Of particular concern in industrialised countries are the highly resistant waterborne protozoal infections as well as the increased travel and immigration, which increase the exposure to exotic diseases. The increased demand for animal proteins in developing countries will lead to an intensification of the production systems in which the risk of zoonotic infections needs to be assessed. Overall, there is an urgent need for better monitoring and control of food-borne parasites using new technologies.
PMID: 19559535 [PubMed - as supplied by publisher]
A novel family Of apicomplexan glideosome associated proteins With an inner-membrane anchoring role
J Biol Chem. 2009 Jun 26. [Epub ahead of print]
A novel family Of apicomplexan glideosome associated proteins With an inner-membrane anchoring role
Bullen HE, Tonkin CJ, O'Donnell RA, Tham WH, Papenfuss AT, Gould S, Cowman AF, Crabb BS, Gilson PR.
The Burnet Institute, Australia;
The phylum Apicomplexa are a group of obligate intracellular parasites responsible for a wide range of important diseases. Central to the lifecycle of these unicellular parasites is their ability to migrate through animal tissue and invade target host cells. Apicomplexan movement is generated by a unique system of gliding motility in which substrate adhesins and invasion-related proteins are pulled across the plasma membrane by an underlying actin-myosin motor. The myosins of this motor are inserted into a dual membrane layer called the inner membrane complex (IMC) that is sandwiched between the plasma membrane and an underlying cytoskeletal basket. Central to our understanding of gliding motility is the characterisation of proteins residing within the IMC but to date only a few proteins are known. We report here a novel family of six-pass-transmembrane proteins, termed the GAPM family, which are highly conserved and specific to Apicomplexa. In Plasmodium falciparum and Toxoplasma gondii the GAPMs localise to the IMC where they form highly SDS-resistant oligomeric complexes. The GAPMs co-purify with the cytoskeletal alveolin proteins and also to some degree with the actin-myosin motor itself. Hence, these proteins are strong candidates for an IMC anchoring role, either directly or indirectly tethering the motor to the cytoskeleton.
PMID: 19561073 [PubMed - as supplied by publisher]
A novel family Of apicomplexan glideosome associated proteins With an inner-membrane anchoring role
Bullen HE, Tonkin CJ, O'Donnell RA, Tham WH, Papenfuss AT, Gould S, Cowman AF, Crabb BS, Gilson PR.
The Burnet Institute, Australia;
The phylum Apicomplexa are a group of obligate intracellular parasites responsible for a wide range of important diseases. Central to the lifecycle of these unicellular parasites is their ability to migrate through animal tissue and invade target host cells. Apicomplexan movement is generated by a unique system of gliding motility in which substrate adhesins and invasion-related proteins are pulled across the plasma membrane by an underlying actin-myosin motor. The myosins of this motor are inserted into a dual membrane layer called the inner membrane complex (IMC) that is sandwiched between the plasma membrane and an underlying cytoskeletal basket. Central to our understanding of gliding motility is the characterisation of proteins residing within the IMC but to date only a few proteins are known. We report here a novel family of six-pass-transmembrane proteins, termed the GAPM family, which are highly conserved and specific to Apicomplexa. In Plasmodium falciparum and Toxoplasma gondii the GAPMs localise to the IMC where they form highly SDS-resistant oligomeric complexes. The GAPMs co-purify with the cytoskeletal alveolin proteins and also to some degree with the actin-myosin motor itself. Hence, these proteins are strong candidates for an IMC anchoring role, either directly or indirectly tethering the motor to the cytoskeleton.
PMID: 19561073 [PubMed - as supplied by publisher]
Thursday, June 25, 2009
Toxoplasma gondii: host-parasite interaction and behavior manipulation
Parasitol Res. 2009 Jun 23. [Epub ahead of print]
Toxoplasma gondii: host-parasite interaction and behavior manipulation
da Silva RC, Langoni H.
Department of Veterinary Hygiene and Animal Science (DHVSP), College of Veterinary Medicine and Animal Science (FMVZ), São Paulo State University (UNESP), Campus of Botucatu, Botucatu, São Paulo, Brazil, silva_rcd@yahoo.com.br.
Toxoplasma gondii is an obligate intracellular parasite that causes different lesions in men and other warm-blooded animals. Humoral and cellular immune response of the host against the parasite keeps the protozoan in a latent stage, and clinical disease ensues when immunological response is compromised. Brain parasitism benefits the parasite causing behavioral changes in the host, not only in animals but also in humans. Schizophrenia and epilepsy are two neurological disorders that have recently been reported to affect humans coinfected with T. gondii. Further studies based on host-parasite interaction in several wild or domestic warm-blooded species are still necessary in order to better understand parasitism and behavioral changes caused by T. gondii.
PMID: 19548003 [PubMed - as supplied by publisher]
Toxoplasma gondii: host-parasite interaction and behavior manipulation
da Silva RC, Langoni H.
Department of Veterinary Hygiene and Animal Science (DHVSP), College of Veterinary Medicine and Animal Science (FMVZ), São Paulo State University (UNESP), Campus of Botucatu, Botucatu, São Paulo, Brazil, silva_rcd@yahoo.com.br.
Toxoplasma gondii is an obligate intracellular parasite that causes different lesions in men and other warm-blooded animals. Humoral and cellular immune response of the host against the parasite keeps the protozoan in a latent stage, and clinical disease ensues when immunological response is compromised. Brain parasitism benefits the parasite causing behavioral changes in the host, not only in animals but also in humans. Schizophrenia and epilepsy are two neurological disorders that have recently been reported to affect humans coinfected with T. gondii. Further studies based on host-parasite interaction in several wild or domestic warm-blooded species are still necessary in order to better understand parasitism and behavioral changes caused by T. gondii.
PMID: 19548003 [PubMed - as supplied by publisher]
The IFN-gamma +874T/A gene polymorphism is associated with retinochoroiditis toxoplasmosis susceptibility
Mem Inst Oswaldo Cruz. 2009 May;104(3):451-5
The IFN-gamma +874T/A gene polymorphism is associated with retinochoroiditis toxoplasmosis susceptibility
de Albuquerque MC, Aleixo AL, Benchimol EI, Leandro AC, das Neves LB, Vicente RT, Bonecini-Almeida Mda G, Amendoeira MR.
Laboratório de Toxoplasmose, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, RJ, Brasil.
Toxoplasmosis is a worldwide zoonosis that generally produces an asymptomatic infection. In some cases, however, toxoplasmosis infection can lead to ocular damage. The immune system has a crucial role in both the course of the infection and in the evolution of toxoplasmosis disease. In particular, IFN-gamma plays an important role in resistance to toxoplasmosis. Polymorphisms in genes encoding cytokines have been shown to have an association with susceptibility to parasitic diseases. The aim of this work was to analyse the occurrence of polymorphisms in the gene encoding IFN-gamma (+874T/A) among Toxoplasma gondii seropositive individuals, including those with ocular lesions caused by the parasite, from a rural population of Santa Rita de Cássia, Barra Mansa, state of Rio de Janeiro, Brazil. Further, we verified which of these polymorphisms could be related to susceptibility to the development of ocular toxoplasmosis. This study included 34 individuals with ocular toxoplasmosis (ocular group) and 134 without ocular lesions (control group). The differences between A and T allele distributions were not statistically significant between the two groups. However, we observed that a higher frequency of individuals from the ocular group possessed the A/A genotype, when compared with the control group, suggesting that homozygocity for the A allele could enhance susceptibility to ocular toxoplasmosis in T. gondii infection.
Publication Types:
Research Support, Non-U.S. Gov't
PMID: 19547871 [PubMed - in process]
The IFN-gamma +874T/A gene polymorphism is associated with retinochoroiditis toxoplasmosis susceptibility
de Albuquerque MC, Aleixo AL, Benchimol EI, Leandro AC, das Neves LB, Vicente RT, Bonecini-Almeida Mda G, Amendoeira MR.
Laboratório de Toxoplasmose, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, RJ, Brasil.
Toxoplasmosis is a worldwide zoonosis that generally produces an asymptomatic infection. In some cases, however, toxoplasmosis infection can lead to ocular damage. The immune system has a crucial role in both the course of the infection and in the evolution of toxoplasmosis disease. In particular, IFN-gamma plays an important role in resistance to toxoplasmosis. Polymorphisms in genes encoding cytokines have been shown to have an association with susceptibility to parasitic diseases. The aim of this work was to analyse the occurrence of polymorphisms in the gene encoding IFN-gamma (+874T/A) among Toxoplasma gondii seropositive individuals, including those with ocular lesions caused by the parasite, from a rural population of Santa Rita de Cássia, Barra Mansa, state of Rio de Janeiro, Brazil. Further, we verified which of these polymorphisms could be related to susceptibility to the development of ocular toxoplasmosis. This study included 34 individuals with ocular toxoplasmosis (ocular group) and 134 without ocular lesions (control group). The differences between A and T allele distributions were not statistically significant between the two groups. However, we observed that a higher frequency of individuals from the ocular group possessed the A/A genotype, when compared with the control group, suggesting that homozygocity for the A allele could enhance susceptibility to ocular toxoplasmosis in T. gondii infection.
Publication Types:
Research Support, Non-U.S. Gov't
PMID: 19547871 [PubMed - in process]
In vitro culture combined with quantitative TaqMan PCR for the assessment of Toxoplasma gondii tissue cyst viability
Vet Parasitol. 2009 Jun 6. [Epub ahead of print]
In vitro culture combined with quantitative TaqMan PCR for the assessment of Toxoplasma gondii tissue cyst viability
Zintl A, Halova D, Mulcahy G, O'Donovan J, Markey B, Dewaal T.
School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland.
Toxoplasma gondii is a serious food-borne pathogen with a worldwide distribution. In order to assess the risk of contracting toxoplasmosis from certain foods, many studies rely on the molecular detection of T. gondii DNA. However, determining the viability of parasites in positive samples is much more problematic. In this paper we describe a novel viability assay that relies on semi-quantitative comparison of the amount of parasite DNA present in samples used to infect host cell monolayers in vitro, and the amount of DNA detected in the same monolayers after 23 days incubation. Our assay is robust, easy to perform and interpret and offers a viable alternative to bioassays, for use in epidemiological studies, or the evaluation of specific food safety treatments.
PMID: 19545946 [PubMed - as supplied by publisher]
In vitro culture combined with quantitative TaqMan PCR for the assessment of Toxoplasma gondii tissue cyst viability
Zintl A, Halova D, Mulcahy G, O'Donovan J, Markey B, Dewaal T.
School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland.
Toxoplasma gondii is a serious food-borne pathogen with a worldwide distribution. In order to assess the risk of contracting toxoplasmosis from certain foods, many studies rely on the molecular detection of T. gondii DNA. However, determining the viability of parasites in positive samples is much more problematic. In this paper we describe a novel viability assay that relies on semi-quantitative comparison of the amount of parasite DNA present in samples used to infect host cell monolayers in vitro, and the amount of DNA detected in the same monolayers after 23 days incubation. Our assay is robust, easy to perform and interpret and offers a viable alternative to bioassays, for use in epidemiological studies, or the evaluation of specific food safety treatments.
PMID: 19545946 [PubMed - as supplied by publisher]
Toxoplasma gondii: Proteomic analysis of antigenicity of soluble tachyzoite antigen
Exp Parasitol. 2009 Jan 29. [Epub ahead of print]
Toxoplasma gondii: Proteomic analysis of antigenicity of soluble tachyzoite antigen
Ma GY, Zhang JZ, Yin GR, Zhang JH, Meng XL, Zhao F.
Research Institute of Medical Parasitology, Shanxi Medical University, P. R. China; National Institute for Communicable Disease Control and Prevention (ICDC), Chinese Center for Disease Control and Prevention (China CDC), P. R. China.
The obligate intracellular parasite Toxoplasma gondii is an important pathogen of humans and animals. The tachyzoite of T. gondii is the main life-cycle stage that is responsible for toxoplasmosis. Study of the antigenicity of soluble tachyzoite antigen (STAg) is important for discovery of protective antigens which will aid in the detection and prevention of toxoplasmosis. At present, no complete proteome map of T. gondii STAg is established, although a large-scale whole proteomic analysis of tachyzoites is underway. In this study, 1227 protein spots of T. gondii soluble tachyzoite antigen (STAg) were fractionated by 2-dimensional electrophoresis (2-DE) at pH range 3-10. By mass spectrometry (MS) analysis, among the separated 1227 protein spots, 426 were identified by searching the Swissport and NCBI nr databases. 230 of these identified spots (230/426, 54%) were demonstrated to be T. gondii protein by MS. Of the 21 Toxoplasma protein spots identified by western blot with rabbit anti-T. gondii serum, 16 had immunoregulatory functions and 5 had immune defense functions. Due to multiple spots for a single protein, these 16 spots represented 11 proteins: a putative protein disulfide isomerase (PDIs), a heat shock protein 60 (Hsp60), a pyruvate kinase (PK), a putative glutamate dehydrogenase (GDH), a coronin, a heat shock protein 70 (Hsp70), a protein kinase C receptor 1 (RACK1), a malate dehydrogenase (MDH), a major surface antigen 1 (SAG1), an uridine phosphorylase (UPase) and a peroxiredoxin (Prx). Among the identified 11 proteins, except that the antigenicity and immunogenicity of the SAG1 has been reported and antigenicity of Hsp70 has disputed, the remaining antigenic proteins were first identified in this study. In conclusion, we obtained 9 novel types of immunogenic proteins that might be potential candidates of vaccine development for toxoplasmosis, which we will confirm in later studies.
PMID: 19545523 [PubMed - as supplied by publisher]
Toxoplasma gondii: Proteomic analysis of antigenicity of soluble tachyzoite antigen
Ma GY, Zhang JZ, Yin GR, Zhang JH, Meng XL, Zhao F.
Research Institute of Medical Parasitology, Shanxi Medical University, P. R. China; National Institute for Communicable Disease Control and Prevention (ICDC), Chinese Center for Disease Control and Prevention (China CDC), P. R. China.
The obligate intracellular parasite Toxoplasma gondii is an important pathogen of humans and animals. The tachyzoite of T. gondii is the main life-cycle stage that is responsible for toxoplasmosis. Study of the antigenicity of soluble tachyzoite antigen (STAg) is important for discovery of protective antigens which will aid in the detection and prevention of toxoplasmosis. At present, no complete proteome map of T. gondii STAg is established, although a large-scale whole proteomic analysis of tachyzoites is underway. In this study, 1227 protein spots of T. gondii soluble tachyzoite antigen (STAg) were fractionated by 2-dimensional electrophoresis (2-DE) at pH range 3-10. By mass spectrometry (MS) analysis, among the separated 1227 protein spots, 426 were identified by searching the Swissport and NCBI nr databases. 230 of these identified spots (230/426, 54%) were demonstrated to be T. gondii protein by MS. Of the 21 Toxoplasma protein spots identified by western blot with rabbit anti-T. gondii serum, 16 had immunoregulatory functions and 5 had immune defense functions. Due to multiple spots for a single protein, these 16 spots represented 11 proteins: a putative protein disulfide isomerase (PDIs), a heat shock protein 60 (Hsp60), a pyruvate kinase (PK), a putative glutamate dehydrogenase (GDH), a coronin, a heat shock protein 70 (Hsp70), a protein kinase C receptor 1 (RACK1), a malate dehydrogenase (MDH), a major surface antigen 1 (SAG1), an uridine phosphorylase (UPase) and a peroxiredoxin (Prx). Among the identified 11 proteins, except that the antigenicity and immunogenicity of the SAG1 has been reported and antigenicity of Hsp70 has disputed, the remaining antigenic proteins were first identified in this study. In conclusion, we obtained 9 novel types of immunogenic proteins that might be potential candidates of vaccine development for toxoplasmosis, which we will confirm in later studies.
PMID: 19545523 [PubMed - as supplied by publisher]
Toxoplasma gondii: Sensitive and rapid detection of infection by loop-mediated isothermal amplification (LAMP) method
Exp Parasitol. 2009 Jan 31. [Epub ahead of print]
Toxoplasma gondii: Sensitive and rapid detection of infection by loop-mediated isothermal amplification (LAMP) method
Zhang H, M Thekisoe OM, Aboge GO, Kyan H, Yamagishi J, Inoue N, Nishikawa Y, Zakimi S, Xuan X.
National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan.
Loop-mediated isothermal amplification (LAMP) method amplifies DNA with high specificity, sensitivity and rapidity. In this study, we used a conserved sequence in the 200 to 300 fold repetitive 529 bp gene of Toxoplasma gondii to design primers for LAMP test. Detection limit of T. gondii LAMP assay with the primers is 1 pg/muL of T. gondii DNA, which was evaluated using ten-fold serially diluted DNA of cultured parasites. Furthermore, LAMP and conventional PCR methods were applied for amplification of the T. gondii DNA extracted from the lymph nodes taken from pigs which were suspected to be Toxoplasma infection. As a result, 76.9% (70/91) and 85.7% (78/91) of the samples were positive on PCR and LAMP analyses, respectively. Therefore, the LAMP has a potential to be applied as an alternative molecular diagnostic tool for detection of T. gondii infection from veterinary samples. This is the first study, which applies the LAMP method to diagnose Toxoplasma from veterinary samples.
PMID: 19545521 [PubMed - as supplied by publisher]
Toxoplasma gondii: Sensitive and rapid detection of infection by loop-mediated isothermal amplification (LAMP) method
Zhang H, M Thekisoe OM, Aboge GO, Kyan H, Yamagishi J, Inoue N, Nishikawa Y, Zakimi S, Xuan X.
National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan.
Loop-mediated isothermal amplification (LAMP) method amplifies DNA with high specificity, sensitivity and rapidity. In this study, we used a conserved sequence in the 200 to 300 fold repetitive 529 bp gene of Toxoplasma gondii to design primers for LAMP test. Detection limit of T. gondii LAMP assay with the primers is 1 pg/muL of T. gondii DNA, which was evaluated using ten-fold serially diluted DNA of cultured parasites. Furthermore, LAMP and conventional PCR methods were applied for amplification of the T. gondii DNA extracted from the lymph nodes taken from pigs which were suspected to be Toxoplasma infection. As a result, 76.9% (70/91) and 85.7% (78/91) of the samples were positive on PCR and LAMP analyses, respectively. Therefore, the LAMP has a potential to be applied as an alternative molecular diagnostic tool for detection of T. gondii infection from veterinary samples. This is the first study, which applies the LAMP method to diagnose Toxoplasma from veterinary samples.
PMID: 19545521 [PubMed - as supplied by publisher]
Over-expression of lactate dehydrogenase enhances differentiation under alkaline conditions
Exp Parasitol. 2009 Feb 5. [Epub ahead of print]
Toxoplasma gondii : over-expression of lactate dehydrogenase enhances differentiation under alkaline conditions
Liwak U, Ananvoranich S.
Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Avenue, Windsor, ON, N9B 3P4, Canada.
Toxoplasma gondii, an intracellular parasite, has two distinctive growth stages, namely rapidly growing tachzyoites and slowly growing bradyzoites. Here we report a unique physiological function of the last committed glycolytic enzyme of T. gondii, lactate dehydrogenase (TgLDH), which is present in two isoforms and expressed in a stage-specific manner. TgLDH1 is present in tachyzoites while TgLDH2 is found in bradyzoites. Using clonal transgenic parasites over-expressing either TgLDH1 or TgLDH2, we showed that the enzymatic activity, growth and virulence of tachyzoites were unaffected by the presence of the recombinant protein. Interestingly, under alkaline conditions the presence of the recombinant TgLDH proteins increased the differentiation, as detected by the formation of cyst structures in vitro, while green fluorescent protein did not. The differentiation enhancement of the recombinant TgLDH1 and TgLDH2 strongly suggests that TgLDH1 and TgLDH2 have an important physiological function, in addition to being glycolytic enzymes and differentiation markers.
PMID: 19545518 [PubMed - as supplied by publisher]
Toxoplasma gondii : over-expression of lactate dehydrogenase enhances differentiation under alkaline conditions
Liwak U, Ananvoranich S.
Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Avenue, Windsor, ON, N9B 3P4, Canada.
Toxoplasma gondii, an intracellular parasite, has two distinctive growth stages, namely rapidly growing tachzyoites and slowly growing bradyzoites. Here we report a unique physiological function of the last committed glycolytic enzyme of T. gondii, lactate dehydrogenase (TgLDH), which is present in two isoforms and expressed in a stage-specific manner. TgLDH1 is present in tachyzoites while TgLDH2 is found in bradyzoites. Using clonal transgenic parasites over-expressing either TgLDH1 or TgLDH2, we showed that the enzymatic activity, growth and virulence of tachyzoites were unaffected by the presence of the recombinant protein. Interestingly, under alkaline conditions the presence of the recombinant TgLDH proteins increased the differentiation, as detected by the formation of cyst structures in vitro, while green fluorescent protein did not. The differentiation enhancement of the recombinant TgLDH1 and TgLDH2 strongly suggests that TgLDH1 and TgLDH2 have an important physiological function, in addition to being glycolytic enzymes and differentiation markers.
PMID: 19545518 [PubMed - as supplied by publisher]
Wednesday, June 24, 2009
Persistent toxoplasma bradyzoite cysts in the brain
Clin Neuropathol. 2009 May-Jun;28(3):210-2
Persistent toxoplasma bradyzoite cysts in the brain: incidental finding in an immunocompetent patient without evidence of a toxoplasmosis
Pusch L, Romeike B, Deckert M, Mawrin C.
Department of Neuropathology, Friedrich-Schiller University, Jena, Germany.
We report on a 72-year-old patient in whom autopsy demonstrated incidentally intracerebral Toxoplasma gondii cysts, locally restricted in the occipital lobe, in association with only a few CD4+ and CD8+ T cells and a mild microglial activation. The patient was HIV-negative. Serologically, there was no evidence for an active inflammation (Toxoplasma gondii specific antibody IgG-positive, IgM-negative). This unusual observation may indicate that in patients with sepsis, who may yield to a state of immunodysbalance, a focal reactivation of parasites may ensue in the absence of conditions predisposing for opportunistic infection.
PMID: 19537140
Persistent toxoplasma bradyzoite cysts in the brain: incidental finding in an immunocompetent patient without evidence of a toxoplasmosis
Pusch L, Romeike B, Deckert M, Mawrin C.
Department of Neuropathology, Friedrich-Schiller University, Jena, Germany.
We report on a 72-year-old patient in whom autopsy demonstrated incidentally intracerebral Toxoplasma gondii cysts, locally restricted in the occipital lobe, in association with only a few CD4+ and CD8+ T cells and a mild microglial activation. The patient was HIV-negative. Serologically, there was no evidence for an active inflammation (Toxoplasma gondii specific antibody IgG-positive, IgM-negative). This unusual observation may indicate that in patients with sepsis, who may yield to a state of immunodysbalance, a focal reactivation of parasites may ensue in the absence of conditions predisposing for opportunistic infection.
PMID: 19537140
Wednesday, June 17, 2009
Role of the parasite and host cytoskeleton in apicomplexa parasitism
Cell Host Microbe. 2009 Jun 18;5(6):602-11
Role of the parasite and host cytoskeleton in apicomplexa parasitism
Frénal K, Soldati-Favre D.
Department of Microbiology and Molecular Medicine, CMU, University of Geneva, 1 rue Michel-Servet, 1211 Geneva 4, Switzerland.
The phylum Apicomplexa includes a large and diverse group of obligate intracellular parasites that rely on actomyosin-based motility to migrate, enter host cells, and egress from infected cells. To ensure their intracellular survival and replication, the apicomplexans have evolved sophisticated strategies for subversion of the host cytoskeleton. Given the properties in common between the host and parasite cytoskeleton, dissecting their individual contribution to the establishment of parasitic infection has been challenging. Nevertheless, recent studies have provided new insights into the mechanisms by which parasites subvert the dynamic properties of host actin and tubulin to promote their entry, development, and egress.
PMID: 19527887 [PubMed - in process]
Role of the parasite and host cytoskeleton in apicomplexa parasitism
Frénal K, Soldati-Favre D.
Department of Microbiology and Molecular Medicine, CMU, University of Geneva, 1 rue Michel-Servet, 1211 Geneva 4, Switzerland.
The phylum Apicomplexa includes a large and diverse group of obligate intracellular parasites that rely on actomyosin-based motility to migrate, enter host cells, and egress from infected cells. To ensure their intracellular survival and replication, the apicomplexans have evolved sophisticated strategies for subversion of the host cytoskeleton. Given the properties in common between the host and parasite cytoskeleton, dissecting their individual contribution to the establishment of parasitic infection has been challenging. Nevertheless, recent studies have provided new insights into the mechanisms by which parasites subvert the dynamic properties of host actin and tubulin to promote their entry, development, and egress.
PMID: 19527887 [PubMed - in process]
Kinetics and phenotype of vaccine-induced CD8+ T cell responses to Toxoplasma
Infect Immun. 2009 Jun 15. [Epub ahead of print]
Kinetics and phenotype of vaccine-induced CD8+ T cell responses to Toxoplasma gondii
Jordan KA, Wilson EH, Tait ED, Fox BA, Roos DS, Bzik DJ, Dzierszinski F, Hunter CA.
Department of Pathobiology, University of Pennsylvania, 380 South University Ave, Philadelphia, PA 19104, USA; Division of Biomedical Sciences, University of California, Riverside, 900 University Ave, Riverside, CA 92521, USA; Department of Microbiology and Immunology, Dartmouth Medical School, 1 Medical Center Drive, Lebanon, HH 03756; Department of Biology, 304B Carolyn Lynch Laboratories, University of Pennsylvania, 380 South University Ave, Philadelphia, PA 19104, USA; Institute of Parasitology, McGill University, 21111 Lakeshore Road, Sainte-Anne-de-Bellevue, Québec H9X 3V9, Canada.
Multiple studies have established that the ability of CD8(+) T cells to act as cytolytic effectors and produce IFN-gamma is important in mediating resistance to the intracellular parasite Toxoplasma gondii. To better understand the generation of the antigen-specific CD8(+) T cell responses induced by T. gondii, mice were immunized with replication-deficient parasites that express the model antigen ovalbumin. Class I tetramers specific for SIINFEKL were used to track the OVA-specific endogenous CD8(+) T cells. The peak CD8(+) T cell response was found at day 10 post-immunization, after which the frequency and numbers of antigen-specific cells declined. Unexpectedly, replication-deficient parasites were found to induce antigen-specific cells with faster kinetics than replicating parasites. Generation of optimal numbers of antigen-specific CD8(+) effector T cells was found to require CD4(+) T cell help. At 7 days following immunization, antigen-specific cells were found to be CD62L(low), KLRG1(+) and CD127(low), and maintained this phenotype for more than 70 days. Antigen-specific CD8(+) effectors T cells in immunized mice exhibited potent perforin-dependent OVA-specific cytolytic activity in vivo. Perforin-dependent cytolysis appeared to be the major cytolytic mechanism; however, a perforin-independent pathway that was not mediated via Fas-FasL was also detected. This study provides further insight into vaccine-induced cytotoxic T lymphocyte (CTL) responses that correlate with protective immunity to T. gondii, and identifies a critical role for CD4(+) T cells in the generation of protective CD8(+) T cell responses.
PMID: 19528214 [PubMed - as supplied by publisher]
Kinetics and phenotype of vaccine-induced CD8+ T cell responses to Toxoplasma gondii
Jordan KA, Wilson EH, Tait ED, Fox BA, Roos DS, Bzik DJ, Dzierszinski F, Hunter CA.
Department of Pathobiology, University of Pennsylvania, 380 South University Ave, Philadelphia, PA 19104, USA; Division of Biomedical Sciences, University of California, Riverside, 900 University Ave, Riverside, CA 92521, USA; Department of Microbiology and Immunology, Dartmouth Medical School, 1 Medical Center Drive, Lebanon, HH 03756; Department of Biology, 304B Carolyn Lynch Laboratories, University of Pennsylvania, 380 South University Ave, Philadelphia, PA 19104, USA; Institute of Parasitology, McGill University, 21111 Lakeshore Road, Sainte-Anne-de-Bellevue, Québec H9X 3V9, Canada.
Multiple studies have established that the ability of CD8(+) T cells to act as cytolytic effectors and produce IFN-gamma is important in mediating resistance to the intracellular parasite Toxoplasma gondii. To better understand the generation of the antigen-specific CD8(+) T cell responses induced by T. gondii, mice were immunized with replication-deficient parasites that express the model antigen ovalbumin. Class I tetramers specific for SIINFEKL were used to track the OVA-specific endogenous CD8(+) T cells. The peak CD8(+) T cell response was found at day 10 post-immunization, after which the frequency and numbers of antigen-specific cells declined. Unexpectedly, replication-deficient parasites were found to induce antigen-specific cells with faster kinetics than replicating parasites. Generation of optimal numbers of antigen-specific CD8(+) effector T cells was found to require CD4(+) T cell help. At 7 days following immunization, antigen-specific cells were found to be CD62L(low), KLRG1(+) and CD127(low), and maintained this phenotype for more than 70 days. Antigen-specific CD8(+) effectors T cells in immunized mice exhibited potent perforin-dependent OVA-specific cytolytic activity in vivo. Perforin-dependent cytolysis appeared to be the major cytolytic mechanism; however, a perforin-independent pathway that was not mediated via Fas-FasL was also detected. This study provides further insight into vaccine-induced cytotoxic T lymphocyte (CTL) responses that correlate with protective immunity to T. gondii, and identifies a critical role for CD4(+) T cells in the generation of protective CD8(+) T cell responses.
PMID: 19528214 [PubMed - as supplied by publisher]
Evolving insights into protein trafficking to the multiple compartments of the apicomplexan plastid
J Eukaryot Microbiol. 2009 May-Jun;56(3):214-20
Evolving insights into protein trafficking to the multiple compartments of the apicomplexan plastid
Parsons M, Karnataki A, Derocher AE.
Seattle Biomedical Research Institute, Washington 98109, USA. marilyn.parsons@sbri.org
The apicoplast is a relict plastid found in many medically important apicomplexan parasites, such as Plasmodium and Toxoplasma. Phylogenetic analysis and the presence of four bounding membranes indicate that the apicoplast arose from a secondary endosymbiosis. Here we review what has been discovered about the complex journey proteins take to reach compartments of the apicoplast. The targeting sequences for luminal proteins are well-defined, but those routing proteins to other compartments are only beginning to be studied. Recent work suggests that the trafficking mechanisms involve a variety of molecules of different phylogenetic origins. We highlight some remaining questions regarding protein trafficking to this divergent organelle.
Publication Types:
Research Support, N.I.H., Extramural
PMID: 19527348 [PubMed - in process]
Evolving insights into protein trafficking to the multiple compartments of the apicomplexan plastid
Parsons M, Karnataki A, Derocher AE.
Seattle Biomedical Research Institute, Washington 98109, USA. marilyn.parsons@sbri.org
The apicoplast is a relict plastid found in many medically important apicomplexan parasites, such as Plasmodium and Toxoplasma. Phylogenetic analysis and the presence of four bounding membranes indicate that the apicoplast arose from a secondary endosymbiosis. Here we review what has been discovered about the complex journey proteins take to reach compartments of the apicoplast. The targeting sequences for luminal proteins are well-defined, but those routing proteins to other compartments are only beginning to be studied. Recent work suggests that the trafficking mechanisms involve a variety of molecules of different phylogenetic origins. We highlight some remaining questions regarding protein trafficking to this divergent organelle.
Publication Types:
Research Support, N.I.H., Extramural
PMID: 19527348 [PubMed - in process]
The role of acidocalcisomes in parasitic protists
J Eukaryot Microbiol. 2009 May-Jun;56(3):208-13
The role of acidocalcisomes in parasitic protists
Moreno SN, Docampo R.
Department of Cellular Biology and Center for Tropical and Global Emerging Diseases, University of Georgia, Athens, 30602, USA. smoreno@cb.uga.edu
Acidocalcisomes are acidic organelles with a high concentration of phosphorus present as pyrophosphate (PP(i)) and polyphosphate (poly P) complexed with calcium and other cations. The acidocalcisome membrane contains a number of pumps (Ca(2+)-ATPase, V-H(+)-ATPase, H(+)-PPase), exchangers (Na(+)/H(+), Ca(2+)/H(+)), and channels (aquaporins), while its matrix contains enzymes related to PP(i) and poly P metabolism. Acidocalcisomes have been observed in pathogenic, as well as non-pathogenic prokaryotes and eukaryotes, e.g. Chlamydomonas reinhardtii, and Dictyostelium discoideum. Some of the potential functions of the acidocalcisome are the storage of cations and phosphorus, the participation of phosphorus in PP(i) and poly P metabolism, calcium homeostasis, maintenance of intracellular pH homeostasis, and osmoregulation. In addition, acidocalcisomes resemble lysosome-related organelles (LRO) from mammalian cells in many of their properties. For example, we found that platelet dense granules, which are LROs, are very similar to acidocalcisomes. They share a similar size, acidic properties, and both contain PP(i), poly P, and calcium. Recent work that indicates that they also share the system for targeting of their membrane proteins through adaptor protein 3 reinforces this concept. The fact that acidocalcisomes interact with other organelles in parasitic protists, e.g. the contractile vacuole in Trypanosoma cruzi, and other vacuoles observed in Toxoplasma gondii, suggests that these cellular compartments may be associated with the endosomal/lysosomal pathway.
Publication Types:
Research Support, N.I.H., Extramural
PMID: 19527347 [PubMed - in process]
The role of acidocalcisomes in parasitic protists
Moreno SN, Docampo R.
Department of Cellular Biology and Center for Tropical and Global Emerging Diseases, University of Georgia, Athens, 30602, USA. smoreno@cb.uga.edu
Acidocalcisomes are acidic organelles with a high concentration of phosphorus present as pyrophosphate (PP(i)) and polyphosphate (poly P) complexed with calcium and other cations. The acidocalcisome membrane contains a number of pumps (Ca(2+)-ATPase, V-H(+)-ATPase, H(+)-PPase), exchangers (Na(+)/H(+), Ca(2+)/H(+)), and channels (aquaporins), while its matrix contains enzymes related to PP(i) and poly P metabolism. Acidocalcisomes have been observed in pathogenic, as well as non-pathogenic prokaryotes and eukaryotes, e.g. Chlamydomonas reinhardtii, and Dictyostelium discoideum. Some of the potential functions of the acidocalcisome are the storage of cations and phosphorus, the participation of phosphorus in PP(i) and poly P metabolism, calcium homeostasis, maintenance of intracellular pH homeostasis, and osmoregulation. In addition, acidocalcisomes resemble lysosome-related organelles (LRO) from mammalian cells in many of their properties. For example, we found that platelet dense granules, which are LROs, are very similar to acidocalcisomes. They share a similar size, acidic properties, and both contain PP(i), poly P, and calcium. Recent work that indicates that they also share the system for targeting of their membrane proteins through adaptor protein 3 reinforces this concept. The fact that acidocalcisomes interact with other organelles in parasitic protists, e.g. the contractile vacuole in Trypanosoma cruzi, and other vacuoles observed in Toxoplasma gondii, suggests that these cellular compartments may be associated with the endosomal/lysosomal pathway.
Publication Types:
Research Support, N.I.H., Extramural
PMID: 19527347 [PubMed - in process]
Friday, June 12, 2009
Plants, endosymbionts and parasites: Abscisic acid and calcium signaling
Commun Integr Biol. 2008 Jul;1(1):62-5.
Plants, endosymbionts and parasites: Abscisic acid and calcium signaling
Nagamune K, Xiong L, Chini E, Sibley LD.
Graduate School of Life and Environmental Sciences; University of Tsukuba; Tsukuba, Ibaraki, Japan.
It was recently discovered that the protozoan parasite, Toxoplasma gondii produces and uses the plant hormone, abscisic acid (ABA), for communication. Following intracellular replication, ABA production influences the timing of parasite egress from the host cell. This density-dependent signal may serve to coordinate exit from the host cell in a synchronous manner by triggering calcium-dependent activation of motility. In the absence of ABA production, parasites undergo differentiation to the semidormant, tissue cyst. The pathway for ABA production in T. gondii may be derived from a relict endosymbiont, acquired by ingestion of a red algal cell. Although the parasite has lost the capacity for photosynthesis, the plant-like nature of this signaling pathway may be exploited to develop new drugs. In support of this idea, an inhibitor of ABA biosynthesis protected mice against lethal infection with T. gondii. Here, we compare the role of ABA in parasites to its activities in plants, where it is know to control development and stress responses.
PMID: 19513200 [PubMed - in process]
Plants, endosymbionts and parasites: Abscisic acid and calcium signaling
Nagamune K, Xiong L, Chini E, Sibley LD.
Graduate School of Life and Environmental Sciences; University of Tsukuba; Tsukuba, Ibaraki, Japan.
It was recently discovered that the protozoan parasite, Toxoplasma gondii produces and uses the plant hormone, abscisic acid (ABA), for communication. Following intracellular replication, ABA production influences the timing of parasite egress from the host cell. This density-dependent signal may serve to coordinate exit from the host cell in a synchronous manner by triggering calcium-dependent activation of motility. In the absence of ABA production, parasites undergo differentiation to the semidormant, tissue cyst. The pathway for ABA production in T. gondii may be derived from a relict endosymbiont, acquired by ingestion of a red algal cell. Although the parasite has lost the capacity for photosynthesis, the plant-like nature of this signaling pathway may be exploited to develop new drugs. In support of this idea, an inhibitor of ABA biosynthesis protected mice against lethal infection with T. gondii. Here, we compare the role of ABA in parasites to its activities in plants, where it is know to control development and stress responses.
PMID: 19513200 [PubMed - in process]
Mic1-3KO tachyzoite a live attenuated vaccine candidate against toxoplasmosis derived from a type I strain shows features of type II strain
Exp Parasitol. 2009 Jun 6. [Epub ahead of print]
Mic1-3KO tachyzoite a live attenuated vaccine candidate against toxoplasmosis derived from a type I strain shows features of type II strain
Moiré N, Dion S, Lebrun M, Dubremetz JF, Poisson ID.
Université François Rabelais de Tours, INRA UMR 483 Université-INRA d'Immunologie Parasitaire et Vaccinologie, Biothérapie anti-infectieuse, IFR agents transmissibles et infectiologie, UFR de Pharmacie, Parc Grandmont, 37200 Tours. FRANCE.
Vaccination with live attenuated parasites has been shown to induce high level of protection against Toxoplasma gondii. In this study we compared the Mic1-3KO tachyzoite (a live attenuated strain) with the parental wild type (WT) tachyzoite in terms of virulence in mice in vivo, dissemination in mouse tissues and persistence in mouse brain. Survival of mice infected with the Mic1-3KO parasites correlated with reduced parasite burden in mouse tissues compared to the parental strain. Like the WT parasite, Mic1-3KO is able to form tissue cysts in vivo which are not, in our experimental conditions, infectious when given by oral route. Infection with the attenuated tachyzoite induced lower levels of cytokine and chemokine than with the parental strain. These data demonstrate that the deleted strain derived from a type I strain behaves like type II strain in outbred mice in terms of virulence, dissemination in mouse tissue and persistence in brain.
PMID: 19508866 [PubMed - as supplied by publisher]
Mic1-3KO tachyzoite a live attenuated vaccine candidate against toxoplasmosis derived from a type I strain shows features of type II strain
Moiré N, Dion S, Lebrun M, Dubremetz JF, Poisson ID.
Université François Rabelais de Tours, INRA UMR 483 Université-INRA d'Immunologie Parasitaire et Vaccinologie, Biothérapie anti-infectieuse, IFR agents transmissibles et infectiologie, UFR de Pharmacie, Parc Grandmont, 37200 Tours. FRANCE.
Vaccination with live attenuated parasites has been shown to induce high level of protection against Toxoplasma gondii. In this study we compared the Mic1-3KO tachyzoite (a live attenuated strain) with the parental wild type (WT) tachyzoite in terms of virulence in mice in vivo, dissemination in mouse tissues and persistence in mouse brain. Survival of mice infected with the Mic1-3KO parasites correlated with reduced parasite burden in mouse tissues compared to the parental strain. Like the WT parasite, Mic1-3KO is able to form tissue cysts in vivo which are not, in our experimental conditions, infectious when given by oral route. Infection with the attenuated tachyzoite induced lower levels of cytokine and chemokine than with the parental strain. These data demonstrate that the deleted strain derived from a type I strain behaves like type II strain in outbred mice in terms of virulence, dissemination in mouse tissue and persistence in brain.
PMID: 19508866 [PubMed - as supplied by publisher]
Immunogenic and protective efficacy of recombinant ROP2 and ROP4 rhoptry proteins in murine experimental toxoplasmosis
Exp Parasitol. 2009 Jun 6. [Epub ahead of print]
Toxoplasma gondii: the immunogenic and protective efficacy of recombinant ROP2 and ROP4 rhoptry proteins in murine experimental toxoplasmosis
Dziadek B, Gatkowska J, Brzostek A, Dziadek J, Dzitko K, Dlugonska H.
Department of Immunoparasitology, University of Lodz, Lodz, Poland.
Toxoplasmosis is a one of the most world-wide spread zoonosis representing a very serious clinical and veterinary problem. In the presented study we evaluated the protective efficacy of a combined recombinant ROP2 and ROP4 subunit vaccine in a chronic Toxoplasma gondii infection in mice. The recombinant ROP2 (rROP2) and ROP4 (rROP4) proteins were cloned and expressed in Escherichia coli and then used for the immunization of C3H/HeJ mice. Both antigens generated a strong systemic mixed Th1/Th2 response polarized towards IgG1 antibody isotype. In contrast to rROP2 stimulating only the specific IL-2 release, rROP4 and crude TLA (Toxoplasma Lysate Antigen) used as a source of native forms of the parasite proteins induced significant proliferation of splenocytes and specific production of IFN-gamma as well as IL-2, the Th1 type cytokines. Challenge of rROP2 and rROP4-vaccinated mice with cysts of low virulent T. gondii DX strain resulted in a partial protection effect with a significantly lower brain parasites load when compared with control animals. In the immunized group of mice the brain cysts number was reduced by nearly 46% as was determined in two independent experiments. These results suggest that, similar to ROP2, rhoptry protein ROP4 could be a very good candidate for future anti-T. gondii multicomponent vaccine based on the recombinant forms of different parasite proteins.
PMID: 19508869 [PubMed - as supplied by publisher]
Toxoplasma gondii: the immunogenic and protective efficacy of recombinant ROP2 and ROP4 rhoptry proteins in murine experimental toxoplasmosis
Dziadek B, Gatkowska J, Brzostek A, Dziadek J, Dzitko K, Dlugonska H.
Department of Immunoparasitology, University of Lodz, Lodz, Poland.
Toxoplasmosis is a one of the most world-wide spread zoonosis representing a very serious clinical and veterinary problem. In the presented study we evaluated the protective efficacy of a combined recombinant ROP2 and ROP4 subunit vaccine in a chronic Toxoplasma gondii infection in mice. The recombinant ROP2 (rROP2) and ROP4 (rROP4) proteins were cloned and expressed in Escherichia coli and then used for the immunization of C3H/HeJ mice. Both antigens generated a strong systemic mixed Th1/Th2 response polarized towards IgG1 antibody isotype. In contrast to rROP2 stimulating only the specific IL-2 release, rROP4 and crude TLA (Toxoplasma Lysate Antigen) used as a source of native forms of the parasite proteins induced significant proliferation of splenocytes and specific production of IFN-gamma as well as IL-2, the Th1 type cytokines. Challenge of rROP2 and rROP4-vaccinated mice with cysts of low virulent T. gondii DX strain resulted in a partial protection effect with a significantly lower brain parasites load when compared with control animals. In the immunized group of mice the brain cysts number was reduced by nearly 46% as was determined in two independent experiments. These results suggest that, similar to ROP2, rhoptry protein ROP4 could be a very good candidate for future anti-T. gondii multicomponent vaccine based on the recombinant forms of different parasite proteins.
PMID: 19508869 [PubMed - as supplied by publisher]
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