APMIS. 2009 Sep;117(9):672-80
Monocytes/macrophages infected with Toxoplasma gondii do not increase co-stimulatory molecules while maintaining their migratory ability
Seipel D, Ribeiro-Gomes FL, Barcelos MW, Ramalho AV, Kanashiro MM, Kipnis TL, Arnholdt AC.
Laboratório de Biologia do Reconhecer, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense. Rio de Janeiro, Brazil.
Toxoplasma gondii is an obligate intracellular parasite that is able to disseminate into deep tissues and cross biological barriers, reaching immunoprivileged sites such as the brain and retina. The parasite is able to infect macrophages and dendritic cells and use them for dispersal throughout the body, but the activation state of those cells is unknown. We investigated the ability of human and murine cells from monocytic/macrophage lineages that had not previously been exposed to inflammatory cytokines to up-regulate co-stimulatory and adhesion molecules upon infection. Toxoplasma gondii-infected human monocytes (freshly isolated and THP1 lineage) were unable to up-regulate CD86, CD83, CD40 or CD1a. CD80 expression increased in infected cells but expression of l-selectin and beta2 integrin was unaltered. We evaluated the ability of infected macrophages from wild type C57/BL/6 or CD14(-/-) mice to migrate in 8 mum transwells. Infected cells from CD14(-/-) mice were more likely to de-adhere than infected cells from wild type mice but they did not show any increase in migratory ability. The non-stimulatory profile of these infected cells may contribute to parasite spread throughout the lymphatic circulation in the initial phases of infection.
Publication Types:
Research Support, Non-U.S. Gov't
PMID: 19703127 [PubMed - in process]
Thursday, August 27, 2009
Azithromycin Inhibits Vertical Transmission of Toxoplasma gondii in Calomys
Placenta. 2009 Aug 22. [Epub ahead of print]
Azithromycin Inhibits Vertical Transmission of Toxoplasma gondii in Calomys callosus (Rodentia: Cricetidae)
Costa IN, Angeloni MB, Santana LA, Barbosa BF, Silva MC, Rodrigues AA, Rostkowsa C, Magalhães PM, Pena JD, Silva DA, Mineo JR, Ferro EA.
Laboratory of Histology and Embriology, Instituto de Ciências Biomédicas, Universidade Federal de Uberlândia, Av. Pará 1720, Bloco 2B, Uberlândia 38405-320, MG, Brazil.
Toxoplasma gondii infection during pregnancy may cause severe consequences to the embryo. Current toxoplasmosis treatment for pregnant women is based on the administration of spiramycin or a drug combination as sulphadiazine-pyrimethamine-folinic acid (SPFA) in cases of confirmed fetal infection. However, these drugs are few tolerated and present many disadvantages due to their toxic effects to the host. The aim of this study was to evaluate the effectiveness of different treatments on the vertical transmission of T. gondii, including azithromycin, Artemisia annua infusion, spiramycin and SPFA in Calomys callosus as model of congenital toxoplasmosis. C. callosus females were perorally infected with 20 cysts of T. gondii ME49 strain at the day that a vaginal plug was observed (1st day of pregnancy - dop). Treatment with azithromycin, A. annua infusion, and spiramycin started at the 4th dop, while the treatment with SPFA started at the 14th dop. Placenta and embryonic tissues were collected for morphological and immunohistochemical analyses, mouse bioassay and PCR from the 15th to 20th dop. No morphological changes were seen in the placenta and embryonic tissues from females treated with azithromycin, spiramycin and SPFA, but embryonic atrophy was observed in animals treated with A. annua infusion. Parasites were found in the placenta and fetal (brain and liver) tissues of animals treated with SPFA, A. annua infusion and spiramycin, although the number of parasites was lower than in non-treated animals. Parasites were also observed in the placenta of animals treated with azithromycin, but not in their embryos. Bioassay and PCR results confirmed the immunohistochemical data. Also, bradyzoite immunostaining was observed only in placental and fetal tissues of animals treated with SPFA. In conclusion, the treatment with azithromycin showed to be more effective, since it was capable to inhibit the vertical transmission of T. gondii in this model of congenital toxoplasmosis.
PMID: 19703714 [PubMed - as supplied by publisher]
Azithromycin Inhibits Vertical Transmission of Toxoplasma gondii in Calomys callosus (Rodentia: Cricetidae)
Costa IN, Angeloni MB, Santana LA, Barbosa BF, Silva MC, Rodrigues AA, Rostkowsa C, Magalhães PM, Pena JD, Silva DA, Mineo JR, Ferro EA.
Laboratory of Histology and Embriology, Instituto de Ciências Biomédicas, Universidade Federal de Uberlândia, Av. Pará 1720, Bloco 2B, Uberlândia 38405-320, MG, Brazil.
Toxoplasma gondii infection during pregnancy may cause severe consequences to the embryo. Current toxoplasmosis treatment for pregnant women is based on the administration of spiramycin or a drug combination as sulphadiazine-pyrimethamine-folinic acid (SPFA) in cases of confirmed fetal infection. However, these drugs are few tolerated and present many disadvantages due to their toxic effects to the host. The aim of this study was to evaluate the effectiveness of different treatments on the vertical transmission of T. gondii, including azithromycin, Artemisia annua infusion, spiramycin and SPFA in Calomys callosus as model of congenital toxoplasmosis. C. callosus females were perorally infected with 20 cysts of T. gondii ME49 strain at the day that a vaginal plug was observed (1st day of pregnancy - dop). Treatment with azithromycin, A. annua infusion, and spiramycin started at the 4th dop, while the treatment with SPFA started at the 14th dop. Placenta and embryonic tissues were collected for morphological and immunohistochemical analyses, mouse bioassay and PCR from the 15th to 20th dop. No morphological changes were seen in the placenta and embryonic tissues from females treated with azithromycin, spiramycin and SPFA, but embryonic atrophy was observed in animals treated with A. annua infusion. Parasites were found in the placenta and fetal (brain and liver) tissues of animals treated with SPFA, A. annua infusion and spiramycin, although the number of parasites was lower than in non-treated animals. Parasites were also observed in the placenta of animals treated with azithromycin, but not in their embryos. Bioassay and PCR results confirmed the immunohistochemical data. Also, bradyzoite immunostaining was observed only in placental and fetal tissues of animals treated with SPFA. In conclusion, the treatment with azithromycin showed to be more effective, since it was capable to inhibit the vertical transmission of T. gondii in this model of congenital toxoplasmosis.
PMID: 19703714 [PubMed - as supplied by publisher]
Tuesday, August 25, 2009
Actin-like protein 1 (ALP1) is a component of dynamic, high molecular weight complexes in Toxoplasma
Cell Motil Cytoskeleton. 2009 Aug 21. [Epub ahead of print]
Actin-like protein 1 (ALP1) is a component of dynamic, high molecular weight complexes in Toxoplasma gondii
Gordon JL, Buguliskis JS, Buske PJ, Sibley LD.
Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri.
Apicomplexan parasites, such as Toxoplasma gondii, rely on actin-based motility for cell invasion, yet conventional actin does not appear to be required for cell division in these parasites. Apicomplexans also contain a variety of actin-related proteins (Arps); however, most of these not directly orthologous to Arps in well-studied systems. We recently identified an apicomplexan-specific member of this family called Actin-Like Protein 1, (ALP1), which plays a role in the assembly of vesicular components recruited to the inner membrane complex (IMC) of daughter cells during cell division. In addition to its enrichment at daughter cell membranes, ALP1 is localized throughout the cytoplasm both diffusely distributed and concentrated in clusters that are detected by fluorescence microscopy, suggesting it forms complexes. Using quantitative optical imaging methods, including fluorescence recovery after photobleaching (FRAP) and fluorescence loss in photobleaching (FLIP), we demonstrated that ALP1 is a component of a large complex, and that it readily exchanges between diffusible and complex-bound forms. Sedimentation and density gradient analyses revealed that ALP1 is found in a freely soluble state as well as high molecular weight complexes. During cell division, ALP1 was dynamically associated with the IMC, suggesting it rapidly cycles between freely diffusible and complex forms during daughter cell assembly. Cell Motil. Cytoskeleton 2009. (c) 2009 Wiley-Liss, Inc.
PMID: 19701930 [PubMed - as supplied by publisher]
Actin-like protein 1 (ALP1) is a component of dynamic, high molecular weight complexes in Toxoplasma gondii
Gordon JL, Buguliskis JS, Buske PJ, Sibley LD.
Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri.
Apicomplexan parasites, such as Toxoplasma gondii, rely on actin-based motility for cell invasion, yet conventional actin does not appear to be required for cell division in these parasites. Apicomplexans also contain a variety of actin-related proteins (Arps); however, most of these not directly orthologous to Arps in well-studied systems. We recently identified an apicomplexan-specific member of this family called Actin-Like Protein 1, (ALP1), which plays a role in the assembly of vesicular components recruited to the inner membrane complex (IMC) of daughter cells during cell division. In addition to its enrichment at daughter cell membranes, ALP1 is localized throughout the cytoplasm both diffusely distributed and concentrated in clusters that are detected by fluorescence microscopy, suggesting it forms complexes. Using quantitative optical imaging methods, including fluorescence recovery after photobleaching (FRAP) and fluorescence loss in photobleaching (FLIP), we demonstrated that ALP1 is a component of a large complex, and that it readily exchanges between diffusible and complex-bound forms. Sedimentation and density gradient analyses revealed that ALP1 is found in a freely soluble state as well as high molecular weight complexes. During cell division, ALP1 was dynamically associated with the IMC, suggesting it rapidly cycles between freely diffusible and complex forms during daughter cell assembly. Cell Motil. Cytoskeleton 2009. (c) 2009 Wiley-Liss, Inc.
PMID: 19701930 [PubMed - as supplied by publisher]
Molecular analyses of Toxoplasma gondii calmodulin-like domain protein kinase isoform 3
Parasitol Int. 2009 Aug 19. [Epub ahead of print]
Molecular analyses of Toxoplasma gondii calmodulin-like domain protein kinase isoform 3
Sugi T, Kato K, Kobayashi K, Pandey K, Takemae H, Kurokawa H, Tohya Y, Akashi H.
Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
Ca(2+) signaling is thought to play an important role in Toxoplasma gondii motility, including invasion of and egress from host cells. Recently, it has been reported that phosphorylation of the glideosome apparatus components of T. gondii occurs during invasion. To elucidate the role of T. gondii calmodulin-like domain protein kinase in the signaling pathway that bridges Ca(2+) stimulation and motility, we characterized T. gondii calmodulin-like domain protein kinase isoform 3 (TgCDPKif3). TgCDPKif3 is homologous to Plasmodium falciparum calcium-dependent protein kinase 1, which has been reported to phosphorylate P. falciparum glideosome components. TgCDPKif3 was purified as a fusion protein that was labeled with [gamma-(32)P]ATP, and the label was subsequently removed by phosphatase treatment. Phosphorylation was eliminated when the putative catalytic lysine residue of TgCDPKif3 was replaced with alanine. TgCDPKif3 phosphorylated Histone II(AS) as a representative substrate in a Ca(2+)-dependent manner at a high Ca(2+) concentration. TgCDPKif3 was localized to the apical ends of tachyzoites. TgCDPKif3 showed the translocation between intra- and extracellular tachyzoites. TgCDPKif3 could phosphorylate T. gondii aldolase 1 (TgALD1) in vitro. The interaction between TgCDPKif3 and TgALD1 was confirmed by the co-immunoprecipitation assay in mammal cells. We suggested that TgCDPKif3 could participate in the motility of T. gondii through the phosphorylation of glideosome complex member.
PMID: 19699312 [PubMed - as supplied by publisher]
Molecular analyses of Toxoplasma gondii calmodulin-like domain protein kinase isoform 3
Sugi T, Kato K, Kobayashi K, Pandey K, Takemae H, Kurokawa H, Tohya Y, Akashi H.
Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
Ca(2+) signaling is thought to play an important role in Toxoplasma gondii motility, including invasion of and egress from host cells. Recently, it has been reported that phosphorylation of the glideosome apparatus components of T. gondii occurs during invasion. To elucidate the role of T. gondii calmodulin-like domain protein kinase in the signaling pathway that bridges Ca(2+) stimulation and motility, we characterized T. gondii calmodulin-like domain protein kinase isoform 3 (TgCDPKif3). TgCDPKif3 is homologous to Plasmodium falciparum calcium-dependent protein kinase 1, which has been reported to phosphorylate P. falciparum glideosome components. TgCDPKif3 was purified as a fusion protein that was labeled with [gamma-(32)P]ATP, and the label was subsequently removed by phosphatase treatment. Phosphorylation was eliminated when the putative catalytic lysine residue of TgCDPKif3 was replaced with alanine. TgCDPKif3 phosphorylated Histone II(AS) as a representative substrate in a Ca(2+)-dependent manner at a high Ca(2+) concentration. TgCDPKif3 was localized to the apical ends of tachyzoites. TgCDPKif3 showed the translocation between intra- and extracellular tachyzoites. TgCDPKif3 could phosphorylate T. gondii aldolase 1 (TgALD1) in vitro. The interaction between TgCDPKif3 and TgALD1 was confirmed by the co-immunoprecipitation assay in mammal cells. We suggested that TgCDPKif3 could participate in the motility of T. gondii through the phosphorylation of glideosome complex member.
PMID: 19699312 [PubMed - as supplied by publisher]
Structural and functional diversity in the family of small heat shock proteins from Toxoplasma
Biochim Biophys Acta. 2009 Aug 19. [Epub ahead of print]
Structural and functional diversity in the family of small heat shock proteins from the parasite Toxoplasma gondii
de Miguel N, Braun N, Bepperling A, Kriehuber T, Kastenmüller A, Buchner J, Angel SO, Haslbeck M.
Laboratorio de Parasitologia Molecular, Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús, Chascomús, Argentina.
Small heat shock proteins (sHsps) are ubiquitous molecular chaperones which prevent the nonspecific aggregation of non-native proteins. Five potential sHsps exist in the parasite Toxoplasma gondii. They are located in different intracellular compartments including mitochondria and are differentially expressed during the parasite;s life cycle. Here, we analysed the structural and functional properties of all five proteins. Interestingly, this first in vitro characterization of sHsps from protists showed that all T. gondii sHsps exhibit the characteristic properties of sHsps such as oligomeric structure and chaperone activity. However, differences in their quaternary structure and in their specific chaperone properties exist. On the structural level, the T. gondii sHsps can be divided in small (12 - 18 subunits) and large (24 - 32 subunits) oligomers. Furthermore, they differ in their interaction with non-native proteins. While some bind substrates tightly, others interact more transiently. The chaperone activity of the three more mono-disperse T. gondii sHsps is regulated by temperature with a decrease in temperature leading to the activation of chaperone activity, suggesting an adaption to specific steps of the parasite;s life cycle.
PMID: 19699241 [PubMed - as supplied by publisher]
Structural and functional diversity in the family of small heat shock proteins from the parasite Toxoplasma gondii
de Miguel N, Braun N, Bepperling A, Kriehuber T, Kastenmüller A, Buchner J, Angel SO, Haslbeck M.
Laboratorio de Parasitologia Molecular, Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús, Chascomús, Argentina.
Small heat shock proteins (sHsps) are ubiquitous molecular chaperones which prevent the nonspecific aggregation of non-native proteins. Five potential sHsps exist in the parasite Toxoplasma gondii. They are located in different intracellular compartments including mitochondria and are differentially expressed during the parasite;s life cycle. Here, we analysed the structural and functional properties of all five proteins. Interestingly, this first in vitro characterization of sHsps from protists showed that all T. gondii sHsps exhibit the characteristic properties of sHsps such as oligomeric structure and chaperone activity. However, differences in their quaternary structure and in their specific chaperone properties exist. On the structural level, the T. gondii sHsps can be divided in small (12 - 18 subunits) and large (24 - 32 subunits) oligomers. Furthermore, they differ in their interaction with non-native proteins. While some bind substrates tightly, others interact more transiently. The chaperone activity of the three more mono-disperse T. gondii sHsps is regulated by temperature with a decrease in temperature leading to the activation of chaperone activity, suggesting an adaption to specific steps of the parasite;s life cycle.
PMID: 19699241 [PubMed - as supplied by publisher]
Dynamics of T cell, antigen-presenting cell, and pathogen interactions during recall responses in the lymph node
Immunity. 2009 Aug 21;31(2):342-55
Dynamics of T cell, antigen-presenting cell, and pathogen interactions during recall responses in the lymph node
Chtanova T, Han SJ, Schaeffer M, van Dooren GG, Herzmark P, Striepen B, Robey EA.
Department of Molecular and Cell Biology, Life Sciences Addition, University of California, Berkeley, CA 94720, USA.
Memory T cells circulate through lymph nodes where they are poised to respond rapidly upon re-exposure to a pathogen; however, the dynamics of memory T cell, antigen-presenting cell, and pathogen interactions during recall responses are largely unknown. We used a mouse model of infection with the intracellular protozoan parasite, Toxoplasma gondii, in conjunction with two-photon microscopy, to address this question. After challenge, memory T cells migrated more rapidly than naive T cells, relocalized toward the subcapsular sinus (SCS) near invaded macrophages, and engaged in prolonged interactions with infected cells. Parasite invasion of T cells occurred by direct transfer of the parasite from the target cell into the T cell and corresponded to an antigen-specific increase in the rate of T cell invasion. Our results provide insight into cellular interactions during recall responses and suggest a mechanism of pathogen subversion of the immune response.
Publication Types:
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
PMID: 19699173 [PubMed - in process]
Dynamics of T cell, antigen-presenting cell, and pathogen interactions during recall responses in the lymph node
Chtanova T, Han SJ, Schaeffer M, van Dooren GG, Herzmark P, Striepen B, Robey EA.
Department of Molecular and Cell Biology, Life Sciences Addition, University of California, Berkeley, CA 94720, USA.
Memory T cells circulate through lymph nodes where they are poised to respond rapidly upon re-exposure to a pathogen; however, the dynamics of memory T cell, antigen-presenting cell, and pathogen interactions during recall responses are largely unknown. We used a mouse model of infection with the intracellular protozoan parasite, Toxoplasma gondii, in conjunction with two-photon microscopy, to address this question. After challenge, memory T cells migrated more rapidly than naive T cells, relocalized toward the subcapsular sinus (SCS) near invaded macrophages, and engaged in prolonged interactions with infected cells. Parasite invasion of T cells occurred by direct transfer of the parasite from the target cell into the T cell and corresponded to an antigen-specific increase in the rate of T cell invasion. Our results provide insight into cellular interactions during recall responses and suggest a mechanism of pathogen subversion of the immune response.
Publication Types:
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
PMID: 19699173 [PubMed - in process]
Thiolactomycin analogues as potential anti-Toxoplasma gondii agents
Parasitol Int. 2009 Aug 18. [Epub ahead of print]
Thiolactomycin analogues as potential anti-Toxoplasma gondii agents
Martins-Duarte ES, Jones SM, Gilbert IH, Atella GC, de Souza W, Vommaro RC.
Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, 21941-902 - Rio de Janeiro-RJ, Brazil.
The discovery of new compounds active against Toxoplasma gondii is extremely important due to the severe disease caused by this pathogen in immunocompromised hosts and to congenital infection. Type II fatty acid biosynthesis has shown to be a promising target for drug intervention in toxoplasmosis. Here we describe the inhibitory effect of 8 thiolactomycin (TLM) analogues against tachyzoite-infected LLC-MK(2) cells. The TLM analogues demonstrated anti-T. gondii activity, arresting tachyzoite proliferation with IC(50) values in the micromolar level after 24h and 48h of treatment. Metabolic labelling of extracellular parasites treated with TLM analogues using [(3)H]acetate demonstrated that these drugs affected acylglycerol synthesis. The rapid reduction of parasite load suggests that these compounds have selective cytotoxic effects against T. gondii. Transmission electron microscopy demonstrated that TLM analogues interfered with membrane-bounded organelles and parasite division and this in turn affected parasite development and survival.
PMID: 19698800 [PubMed - as supplied by publisher]
Thiolactomycin analogues as potential anti-Toxoplasma gondii agents
Martins-Duarte ES, Jones SM, Gilbert IH, Atella GC, de Souza W, Vommaro RC.
Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, 21941-902 - Rio de Janeiro-RJ, Brazil.
The discovery of new compounds active against Toxoplasma gondii is extremely important due to the severe disease caused by this pathogen in immunocompromised hosts and to congenital infection. Type II fatty acid biosynthesis has shown to be a promising target for drug intervention in toxoplasmosis. Here we describe the inhibitory effect of 8 thiolactomycin (TLM) analogues against tachyzoite-infected LLC-MK(2) cells. The TLM analogues demonstrated anti-T. gondii activity, arresting tachyzoite proliferation with IC(50) values in the micromolar level after 24h and 48h of treatment. Metabolic labelling of extracellular parasites treated with TLM analogues using [(3)H]acetate demonstrated that these drugs affected acylglycerol synthesis. The rapid reduction of parasite load suggests that these compounds have selective cytotoxic effects against T. gondii. Transmission electron microscopy demonstrated that TLM analogues interfered with membrane-bounded organelles and parasite division and this in turn affected parasite development and survival.
PMID: 19698800 [PubMed - as supplied by publisher]
Friday, August 21, 2009
Treatment with Spiramycin in pregnant women impair the production and the avidity maturation of anti T. gondii specific IgG
Clin Vaccine Immunol. 2009 Aug 19. [Epub ahead of print]
Treatment with Spiramycin of Toxoplasma gondii infection in pregnant women impair the production and the avidity maturation of anti T. gondii specific IgG-antibodies
Meroni V, Genco F, Tinelli C, Lanzarini P, Bollani L, Stronati M, Petersen E.
Department of Infectious Diseases University of Pavia, Pavia, Italy; Department of Infectious Diseases IRCCS Policlinico San Matteo Foundation, Pavia, Italy; Clinical Epidemiology and Biometric Unit, IRCCS Policlinico San Matteo Foundation, Pavia, Italy; Neonatal Intensive Care Unit IRCCS Policlinico San Matteo Foundation, Pavia, Italy; Department of Infectious Diseases Aarhus University Hospital, Skejby Aarhus, Denmark.
The aim of the study was to evaluate the influence of treatment with spiramycin on the increase of IgG titre and IgG-avidity index (AI) in pregnant women with seroconversion from beginning of therapy, until delivery and after delivery. This group was compared with adult patients with recently acquired untreated toxoplasmosis. One hundred and four samples from 32 pregnant women with seroconversion for toxoplasmosis and/or very low IgG AI were followed from the beginning of therapy with spiramycin, until delivery. Twenty nine women were further followed some months after delivery and interruption of therapy. Thirty-eight samples from 16 untreated, non-pregnant patients were evaluated as the control group. T.gondii-specific IgG-antibody and T.gondii-specific IgG-avidity index were significantly delayed in pregnant women receiving therapy compared to non-pregnant controls not treated and the findings were consistent with assays from two different manufacturers. After birth the T.gondii-specific IgG-avidity index increased. Avidity maturation is delayed during pregnancy and treatment, and low avidty antibodies in pregnant women cannot be taken as a sing of infection within three to four months.
PMID: 19692628 [PubMed - as supplied by publisher]
Treatment with Spiramycin of Toxoplasma gondii infection in pregnant women impair the production and the avidity maturation of anti T. gondii specific IgG-antibodies
Meroni V, Genco F, Tinelli C, Lanzarini P, Bollani L, Stronati M, Petersen E.
Department of Infectious Diseases University of Pavia, Pavia, Italy; Department of Infectious Diseases IRCCS Policlinico San Matteo Foundation, Pavia, Italy; Clinical Epidemiology and Biometric Unit, IRCCS Policlinico San Matteo Foundation, Pavia, Italy; Neonatal Intensive Care Unit IRCCS Policlinico San Matteo Foundation, Pavia, Italy; Department of Infectious Diseases Aarhus University Hospital, Skejby Aarhus, Denmark.
The aim of the study was to evaluate the influence of treatment with spiramycin on the increase of IgG titre and IgG-avidity index (AI) in pregnant women with seroconversion from beginning of therapy, until delivery and after delivery. This group was compared with adult patients with recently acquired untreated toxoplasmosis. One hundred and four samples from 32 pregnant women with seroconversion for toxoplasmosis and/or very low IgG AI were followed from the beginning of therapy with spiramycin, until delivery. Twenty nine women were further followed some months after delivery and interruption of therapy. Thirty-eight samples from 16 untreated, non-pregnant patients were evaluated as the control group. T.gondii-specific IgG-antibody and T.gondii-specific IgG-avidity index were significantly delayed in pregnant women receiving therapy compared to non-pregnant controls not treated and the findings were consistent with assays from two different manufacturers. After birth the T.gondii-specific IgG-avidity index increased. Avidity maturation is delayed during pregnancy and treatment, and low avidty antibodies in pregnant women cannot be taken as a sing of infection within three to four months.
PMID: 19692628 [PubMed - as supplied by publisher]
Thursday, August 20, 2009
Genetic diversity of Toxoplasma gondii in animals and humans
Philos Trans R Soc Lond B Biol Sci. 2009 Sep 27;364(1530):2749-61
Genetic diversity of Toxoplasma gondii in animals and humans
Sibley LD, Khan A, Ajioka JW, Rosenthal BM.
Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, MO 63130, USA. sibley@borcim.wsutl.edu
Toxoplasma gondii is one of the most widespread parasites of domestic, wild, and companion animals, and it also commonly infects humans. Toxoplasma gondii has a complex life cycle. Sexual development occurs only in the cat gut, while asexual replication occurs in many vertebrate hosts. These features combine to create an unusual population structure. The vast majority of strains in North America and Europe fall into three recently derived, clonal lineages known as types I, II and III. Recent studies have revealed that South American strains are more genetically diverse and comprise distinct genotypes. These differences have been shaped by infrequent sexual recombination, population sweeps and biogeography. The majority of human infections that have been studied in North America and Europe are caused by type II strains, which are also common in agricultural animals from these regions. In contrast, several diverse genotypes of T. gondii are associated with severe infections in humans in South America. Defining the population structure of T. gondii from new regions has important implications for transmission, immunogenicity and pathogenesis.
Publication Types:
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
PMID: 19687043 [PubMed - in process]
Genetic diversity of Toxoplasma gondii in animals and humans
Sibley LD, Khan A, Ajioka JW, Rosenthal BM.
Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, MO 63130, USA. sibley@borcim.wsutl.edu
Toxoplasma gondii is one of the most widespread parasites of domestic, wild, and companion animals, and it also commonly infects humans. Toxoplasma gondii has a complex life cycle. Sexual development occurs only in the cat gut, while asexual replication occurs in many vertebrate hosts. These features combine to create an unusual population structure. The vast majority of strains in North America and Europe fall into three recently derived, clonal lineages known as types I, II and III. Recent studies have revealed that South American strains are more genetically diverse and comprise distinct genotypes. These differences have been shaped by infrequent sexual recombination, population sweeps and biogeography. The majority of human infections that have been studied in North America and Europe are caused by type II strains, which are also common in agricultural animals from these regions. In contrast, several diverse genotypes of T. gondii are associated with severe infections in humans in South America. Defining the population structure of T. gondii from new regions has important implications for transmission, immunogenicity and pathogenesis.
Publication Types:
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
PMID: 19687043 [PubMed - in process]
Toxoplasma strain nomenclature
J Infect Dis. 2009 Sep 15;200(6):1012
Toxoplasma strain nomenclature
Gómez-Marín JE.
Grupo de Estudio en Parasitología Molecular, Universidad del Quindío, Armenia, Colombia.
PMID: 19686076 [PubMed - in process]
Toxoplasma strain nomenclature
Gómez-Marín JE.
Grupo de Estudio en Parasitología Molecular, Universidad del Quindío, Armenia, Colombia.
PMID: 19686076 [PubMed - in process]
Wednesday, August 19, 2009
Gut Commensal Bacteria Direct a Protective Immune Response against Toxoplasma
Cell Host Microbe. 2009 Aug 20;6(2):187-96
Gut Commensal Bacteria Direct a Protective Immune Response against Toxoplasma gondii
Benson A, Pifer R, Behrendt CL, Hooper LV, Yarovinsky F.
Department of Immunology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA.
Toxoplasma gondii is a universally distributed pathogen that infects over one billion people worldwide. Host resistance to this protozoan parasite depends on a Th1 immune response with potent production of the cytokines interleukin-12 and interferon gamma. Although Toll-like receptor 11 (TLR11) plays a major role in controlling Th1 immunity to this pathogen in mice, this innate immune receptor is nonfunctional in humans, and the mechanisms of TLR11-independent sensing of T. gondii remain elusive. Here, we show that oral infection by T. gondii triggers a TLR11-independent but MyD88-dependent Th1 response that is impaired in TLR2xTLR4 double knockout and TLR9 single knockout mice. These mucosal innate and adaptive immune responses to T. gondii rely on the indirect stimulation of dendritic cells by normal gut microflora. Thus, our results reveal that gut commensal bacteria can serve as molecular adjuvants during parasitic infection, providing indirect immunostimulation that protects against T. gondii in the absence of TLR11.
PMID: 19683684 [PubMed - in process]
Gut Commensal Bacteria Direct a Protective Immune Response against Toxoplasma gondii
Benson A, Pifer R, Behrendt CL, Hooper LV, Yarovinsky F.
Department of Immunology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA.
Toxoplasma gondii is a universally distributed pathogen that infects over one billion people worldwide. Host resistance to this protozoan parasite depends on a Th1 immune response with potent production of the cytokines interleukin-12 and interferon gamma. Although Toll-like receptor 11 (TLR11) plays a major role in controlling Th1 immunity to this pathogen in mice, this innate immune receptor is nonfunctional in humans, and the mechanisms of TLR11-independent sensing of T. gondii remain elusive. Here, we show that oral infection by T. gondii triggers a TLR11-independent but MyD88-dependent Th1 response that is impaired in TLR2xTLR4 double knockout and TLR9 single knockout mice. These mucosal innate and adaptive immune responses to T. gondii rely on the indirect stimulation of dendritic cells by normal gut microflora. Thus, our results reveal that gut commensal bacteria can serve as molecular adjuvants during parasitic infection, providing indirect immunostimulation that protects against T. gondii in the absence of TLR11.
PMID: 19683684 [PubMed - in process]
A Helical Membrane-Binding Domain Targets the Toxoplasma ROP2 Family to the Parasitophorous Vacuole
Traffic. 2009 Jun 22. [Epub ahead of print]
A Helical Membrane-Binding Domain Targets the Toxoplasma ROP2 Family to the Parasitophorous Vacuole
Reese ML, Boothroyd JC.
Department of Microbiology & Immunology, Stanford University School of Medicine, Fairchild Science Building, Room D305, 299 Campus Drive, Stanford, CA 94305-5124, USA.
During invasion, the obligate intracellular pathogen, Toxoplasma gondii, secretes into its host cell a variety of effector molecules, several of which have been implicated in strain-specific variation in disease. The largest family of these effectors, defined by the canonical member ROP2, quickly associates with the nascent parasitophorous vacuole membrane (PVM) after secretion. Here we demonstrate that the NH(2)-terminal domain of the ROP2 family contains a series of amphipathic helices that are necessary and sufficient for membrane association. While each of the amphipathic helices is individually competent to bind cellular membranes, together they act to bind the PVM preferentially, possibly through sensing its strong negative curvature. This previously uncharacterized helical domain is an evolutionarily robust and energetically efficient design for membrane association.
PMID: 19682324 [PubMed - as supplied by publisher]
A Helical Membrane-Binding Domain Targets the Toxoplasma ROP2 Family to the Parasitophorous Vacuole
Reese ML, Boothroyd JC.
Department of Microbiology & Immunology, Stanford University School of Medicine, Fairchild Science Building, Room D305, 299 Campus Drive, Stanford, CA 94305-5124, USA.
During invasion, the obligate intracellular pathogen, Toxoplasma gondii, secretes into its host cell a variety of effector molecules, several of which have been implicated in strain-specific variation in disease. The largest family of these effectors, defined by the canonical member ROP2, quickly associates with the nascent parasitophorous vacuole membrane (PVM) after secretion. Here we demonstrate that the NH(2)-terminal domain of the ROP2 family contains a series of amphipathic helices that are necessary and sufficient for membrane association. While each of the amphipathic helices is individually competent to bind cellular membranes, together they act to bind the PVM preferentially, possibly through sensing its strong negative curvature. This previously uncharacterized helical domain is an evolutionarily robust and energetically efficient design for membrane association.
PMID: 19682324 [PubMed - as supplied by publisher]
Friday, August 14, 2009
Toxoplasma gondii inhibits R5 HIV-1 replication in human lymphoid tissues ex vivo
Microbes Infect. 2009 Aug 8. [Epub ahead of print]
Toxoplasma gondii inhibits R5 HIV-1 replication in human lymphoid tissues ex vivo
Sassi A, Brichacek B, Hieny S, Yarovinsky F, Golding H, Grivel JC, Sher A, Margolis L.
Section of Intercellular Interactions, Program of Physical Biology, National Institute of Child Health and Human Development, Bethesda MD 20892.
Critical events of HIV-1 pathogenesis occur in lymphoid tissues where HIV-1 is typically accompanied by infections with other pathogens (HIV co-pathogens). Co-pathogens greatly affect the clinical course of the disease and the transmission of HIV. The apicomplexan parasite Toxoplasma gondii is a common HIV co-pathogen associated with AIDS development. Here, we examined the interaction of T. gondii and HIV in coinfected human lymphoid tissue ex vivo. Both pathogens readily replicate in ex vivo infected blocks of human tonsillar tissue. Surprisingly, we found that live T. gondii preferentially inhibits R5 HIV-1 replication in coinfected tissues. This effect is reproduced by treatment of the tissue blocks with recombinant C-18, a T. gondii -encoded cyclophilin that binds to CCR5. These ex vivo findings raise the possibility that, in addition to being a co-factor in HIV disease, T. gondii may influence the outcome of viral infection by preferentially suppressing R5 variants.
PMID: 19671446 [PubMed - as supplied by publisher]
Toxoplasma gondii inhibits R5 HIV-1 replication in human lymphoid tissues ex vivo
Sassi A, Brichacek B, Hieny S, Yarovinsky F, Golding H, Grivel JC, Sher A, Margolis L.
Section of Intercellular Interactions, Program of Physical Biology, National Institute of Child Health and Human Development, Bethesda MD 20892.
Critical events of HIV-1 pathogenesis occur in lymphoid tissues where HIV-1 is typically accompanied by infections with other pathogens (HIV co-pathogens). Co-pathogens greatly affect the clinical course of the disease and the transmission of HIV. The apicomplexan parasite Toxoplasma gondii is a common HIV co-pathogen associated with AIDS development. Here, we examined the interaction of T. gondii and HIV in coinfected human lymphoid tissue ex vivo. Both pathogens readily replicate in ex vivo infected blocks of human tonsillar tissue. Surprisingly, we found that live T. gondii preferentially inhibits R5 HIV-1 replication in coinfected tissues. This effect is reproduced by treatment of the tissue blocks with recombinant C-18, a T. gondii -encoded cyclophilin that binds to CCR5. These ex vivo findings raise the possibility that, in addition to being a co-factor in HIV disease, T. gondii may influence the outcome of viral infection by preferentially suppressing R5 variants.
PMID: 19671446 [PubMed - as supplied by publisher]
Wednesday, August 12, 2009
Risk Factors for Toxoplasma gondii Infection in the United States
Clin Infect Dis. 2009 Aug 10. [Epub ahead of print]
Risk Factors for Toxoplasma gondii Infection in the United States
Jones JL, Dargelas V, Roberts J, Press C, Remington JS, Montoya JG.
Division of Parasitic Diseases, National Center for Zoonotic, Vectorborne, and Enteric Diseases, Coordinating Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia; 2Palo Alto Medical Foundation, Toxoplasma Serology Laboratory, Palo Alto, and 3Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California.
Background. Toxoplasmosis can cause severe ocular and neurological disease. We sought to determine risk factors for Toxoplasma gondii infection in the United States. Methods. We conducted a case-control study of adults recently infected with T. gondii. Case patients were selected from the Palo Alto Medical Foundation Toxoplasma Serology Laboratory from August 2002 through May 2007; control patients were randomly selected from among T. gondii-seronegative persons. Data were obtained from serological testing and patient questionnaires. Results. We evaluated 148 case patients with recent T. gondii infection and 413 control patients. In multivariate analysis, an elevated risk of recent T. gondii infection was associated with the following factors: eating raw ground beef (adjusted odds ratio [aOR], 6.67; 95% confidence limits [CLs], 2.09, 21.24; attributable risk [AR], 7%); eating rare lamb (aOR, 8.39; 95% CLs, 3.68, 19.16; AR, 20%); eating locally produced cured, dried, or smoked meat (aOR, 1.97; 95% CLs, 1.18, 3.28; AR, 22%); working with meat (aOR, 3.15; 95% CLs, 1.09, 9.10; AR, 5%); drinking unpasteurized goat's milk (aOR, 5.09; 95% CLs, 1.45, 17.80; AR, 4%); and having 3 or more kittens (aOR, 27.89; 95% CLs, 5.72, 135.86; AR, 10%). Eating raw oysters, clams, or mussels (aOR, 2.22; 95% CLs, 1.07, 4.61; AR, 16%) was significant in a separate model among persons asked this question. Subgroup results are also provided for women and for pregnant women. Conclusions. In the United States, exposure to certain raw or undercooked foods and exposure to kittens are risk factors for T. gondii infection. Knowledge of these risk factors will help to target prevention efforts.
PMID: 19663709 [PubMed - as supplied by publisher]
Risk Factors for Toxoplasma gondii Infection in the United States
Jones JL, Dargelas V, Roberts J, Press C, Remington JS, Montoya JG.
Division of Parasitic Diseases, National Center for Zoonotic, Vectorborne, and Enteric Diseases, Coordinating Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia; 2Palo Alto Medical Foundation, Toxoplasma Serology Laboratory, Palo Alto, and 3Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California.
Background. Toxoplasmosis can cause severe ocular and neurological disease. We sought to determine risk factors for Toxoplasma gondii infection in the United States. Methods. We conducted a case-control study of adults recently infected with T. gondii. Case patients were selected from the Palo Alto Medical Foundation Toxoplasma Serology Laboratory from August 2002 through May 2007; control patients were randomly selected from among T. gondii-seronegative persons. Data were obtained from serological testing and patient questionnaires. Results. We evaluated 148 case patients with recent T. gondii infection and 413 control patients. In multivariate analysis, an elevated risk of recent T. gondii infection was associated with the following factors: eating raw ground beef (adjusted odds ratio [aOR], 6.67; 95% confidence limits [CLs], 2.09, 21.24; attributable risk [AR], 7%); eating rare lamb (aOR, 8.39; 95% CLs, 3.68, 19.16; AR, 20%); eating locally produced cured, dried, or smoked meat (aOR, 1.97; 95% CLs, 1.18, 3.28; AR, 22%); working with meat (aOR, 3.15; 95% CLs, 1.09, 9.10; AR, 5%); drinking unpasteurized goat's milk (aOR, 5.09; 95% CLs, 1.45, 17.80; AR, 4%); and having 3 or more kittens (aOR, 27.89; 95% CLs, 5.72, 135.86; AR, 10%). Eating raw oysters, clams, or mussels (aOR, 2.22; 95% CLs, 1.07, 4.61; AR, 16%) was significant in a separate model among persons asked this question. Subgroup results are also provided for women and for pregnant women. Conclusions. In the United States, exposure to certain raw or undercooked foods and exposure to kittens are risk factors for T. gondii infection. Knowledge of these risk factors will help to target prevention efforts.
PMID: 19663709 [PubMed - as supplied by publisher]
Bilateral Retinochoroiditis Caused By An Atypical Strain Of Toxoplasma gondii
Br J Ophthalmol. 2009 Aug 9. [Epub ahead of print]
Bilateral Retinochoroiditis Caused By An Atypical Strain Of Toxoplasma Gondii
Bottós J, Miller RH, Belfort RN, Macedo AC, Toxoplasmosis Group U, Belfort R Jr, Grigg ME.
Department of Ophthalmology, Federal University of São Paulo, Brazil;
BACKGROUND: A 53-year-old man presented with an acute bilateral posterior uveitis with extensive necrotizing retinochoroiditis but without chorioretinal scarring. A thorough workup did not reveal any underlying disease. The possibilities of atypical ocular toxoplasmosis as well as herpetic retinal necrosis were considered and specific therapy instituted, with little improvement. The patient died within two months as result of an undifferentiated squamous cell carcinoma. METHODS: Histopathological examination, immunohistochemistry and multi-locus polymerase chain reaction confirmed T. gondii infection of the retina. RESULTS: Macroscopic examination of enucleated globe showed extensive retinal necrosis and vitreous detachment. Histological examination of retinal tissue identified numerous round-to-elliptical toxoplasmic cysts within the retina, with retinal necrosis and minimal choroidal inflammation. Immunohistochemical analyses confirmed the cysts were due to Toxoplasma gondii. DNA extracted from formalin-fixed, paraffin-embedded tissue sections was subjected to multi-locus PCR analysis at the following typing loci: SAG1, SAG2, SAG3, SAG4, B1, NTS2, GRA6, and GRA7. DNA sequencing of positive PCR products at the NTS2, SAG1, and GRA7 loci confirmed the presence of a non-archetypal strain of T. gondii infecting the eye of the patient experiencing a severe, atypical ocular toxoplasmosis. CONCLUSION: A highly divergent, non-archetypal strain of Toxoplasma gondii was responsible for causing a severe, atypical bilateral retinochoroiditis in a patient from Brazil.
PMID: 19666926 [PubMed - as supplied by publisher]
Bilateral Retinochoroiditis Caused By An Atypical Strain Of Toxoplasma Gondii
Bottós J, Miller RH, Belfort RN, Macedo AC, Toxoplasmosis Group U, Belfort R Jr, Grigg ME.
Department of Ophthalmology, Federal University of São Paulo, Brazil;
BACKGROUND: A 53-year-old man presented with an acute bilateral posterior uveitis with extensive necrotizing retinochoroiditis but without chorioretinal scarring. A thorough workup did not reveal any underlying disease. The possibilities of atypical ocular toxoplasmosis as well as herpetic retinal necrosis were considered and specific therapy instituted, with little improvement. The patient died within two months as result of an undifferentiated squamous cell carcinoma. METHODS: Histopathological examination, immunohistochemistry and multi-locus polymerase chain reaction confirmed T. gondii infection of the retina. RESULTS: Macroscopic examination of enucleated globe showed extensive retinal necrosis and vitreous detachment. Histological examination of retinal tissue identified numerous round-to-elliptical toxoplasmic cysts within the retina, with retinal necrosis and minimal choroidal inflammation. Immunohistochemical analyses confirmed the cysts were due to Toxoplasma gondii. DNA extracted from formalin-fixed, paraffin-embedded tissue sections was subjected to multi-locus PCR analysis at the following typing loci: SAG1, SAG2, SAG3, SAG4, B1, NTS2, GRA6, and GRA7. DNA sequencing of positive PCR products at the NTS2, SAG1, and GRA7 loci confirmed the presence of a non-archetypal strain of T. gondii infecting the eye of the patient experiencing a severe, atypical ocular toxoplasmosis. CONCLUSION: A highly divergent, non-archetypal strain of Toxoplasma gondii was responsible for causing a severe, atypical bilateral retinochoroiditis in a patient from Brazil.
PMID: 19666926 [PubMed - as supplied by publisher]
Molecular markers of susceptibility to ocular toxoplasmosis, host and guest behaving badly
Clin Ophthalmol. 2008 Dec;2(4):837-48.
Molecular markers of susceptibility to ocular toxoplasmosis, host and guest behaving badly
Vallochi AL, Goldberg AC, Falcai A, Ramasawmy R, Kalil J, Silveira C, Belfort R, Rizzo LV.
Oswaldo Cruz Institution (IOC), Oswaldo Cruz Foundation (FIOCRUZ), Rio de Janeiro, RJ, Brazil.
Infection with Toxoplasma gondii results in retinochoroiditis in 6% to 20% of immunocompetent individuals. The outcome of infection is the result of a set of interactions involving host genetic background, environmental, and social factors, and the genetic background of the parasite, all of which can be further modified by additional infections or even reinfection. Genes that encode several components of the immune system exhibit polymorphisms in their regulatory and coding regions that affect level and type of expression in response to stimuli, directing the immune response into different pathways. These variant alleles have been associated with susceptibility to immune-mediated diseases and with severity of pathology. We have investigated polymorphisms in several of these genes, identified as candidates for progression to retinochoroiditis caused by toxoplasmosis, namely chemokine (C-C motif) receptor 5 (CCR5), toll-like receptor-2 (TLR2), and TLR4. Furthermore, because interleukin-12 (IL-12) has been shown to be fundamental both in mice and in man to control a protective response against T. gondii, molecules that have a key function in IL-12 production will be emphasized in this review, in addition to discussing the importance of the genetic background of the parasite in the establishment of ocular disease.
PMID: 19668438 [PubMed - in process]
Molecular markers of susceptibility to ocular toxoplasmosis, host and guest behaving badly
Vallochi AL, Goldberg AC, Falcai A, Ramasawmy R, Kalil J, Silveira C, Belfort R, Rizzo LV.
Oswaldo Cruz Institution (IOC), Oswaldo Cruz Foundation (FIOCRUZ), Rio de Janeiro, RJ, Brazil.
Infection with Toxoplasma gondii results in retinochoroiditis in 6% to 20% of immunocompetent individuals. The outcome of infection is the result of a set of interactions involving host genetic background, environmental, and social factors, and the genetic background of the parasite, all of which can be further modified by additional infections or even reinfection. Genes that encode several components of the immune system exhibit polymorphisms in their regulatory and coding regions that affect level and type of expression in response to stimuli, directing the immune response into different pathways. These variant alleles have been associated with susceptibility to immune-mediated diseases and with severity of pathology. We have investigated polymorphisms in several of these genes, identified as candidates for progression to retinochoroiditis caused by toxoplasmosis, namely chemokine (C-C motif) receptor 5 (CCR5), toll-like receptor-2 (TLR2), and TLR4. Furthermore, because interleukin-12 (IL-12) has been shown to be fundamental both in mice and in man to control a protective response against T. gondii, molecules that have a key function in IL-12 production will be emphasized in this review, in addition to discussing the importance of the genetic background of the parasite in the establishment of ocular disease.
PMID: 19668438 [PubMed - in process]
Saturday, August 08, 2009
Improvement of dendritic cell based therapeutic cancer vaccine with components of Toxoplasma gondii
Clin Vaccine Immunol. 2009 Aug 5. [Epub ahead of print]
Improvement of dendritic cell based therapeutic cancer vaccine with components of Toxoplasma gondii
Motamedi M, Arab S, Moazzeni SM, Khamis Abadi M, Hadjati J.
Lorestan University of Medical Sciences, Khoramabad, Iran; Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Department of Immunology, Tarbiat Modarres University, Tehran, Iran.
The use of Dendritic cells (DCs) as a cellular adjuvant is a promising approach in immunotherapy of cancer. It has been previously demonstrated that dendritic cells (DCs) pulsed ex vivo with Toxoplasma gondii antigens trigger a systemic Th1-biased specific immune response and induce a protective and specific anti-toxoplasma immunity. In the present study, we demonstrate that tumor antigen pulsed DCs matured in the presence of Toxoplasma gondii components induce a potent anti-tumor response in a mouse model of fibrosarcoma. Bone-marrow derived DCs (BMDCs) were cultured in the presence of GM-CSF and IL-4. After 5 days, tumor lysates with/without T. gondii lysate were added to the culture for another 2 days. Cytokine production in BMDC culture and co culture supernatant of DC and splenic cells was evaluated. For immunization, 7 days after tumor challenge, different groups of Balb/c mice received different kinds of dendritic cells subcutaneously (S.C.) around the tumor site. Tumor growth was monitored and two weeks after DC immunotherapy cytotoxic activity and infiltration of CD8+ T cell monitored in different groups. According to the findings immunotherapy with T.gondii matured dendritic cells led to a significant increase in activity of cytotoxic T cells and decreased tumor growth of immunized animals. Immature DCs didn't cause any change in cytotoxic activity and tumor growth rate compare to normal or controls. The current study suggests that specific anti-tumor immune response can be induced by DCs matured with T.gondii component and provide the basis for the use of T.gondii in DC-targeted clinical therapies.
PMID: 19656994 [PubMed - as supplied by publisher]
Improvement of dendritic cell based therapeutic cancer vaccine with components of Toxoplasma gondii
Motamedi M, Arab S, Moazzeni SM, Khamis Abadi M, Hadjati J.
Lorestan University of Medical Sciences, Khoramabad, Iran; Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Department of Immunology, Tarbiat Modarres University, Tehran, Iran.
The use of Dendritic cells (DCs) as a cellular adjuvant is a promising approach in immunotherapy of cancer. It has been previously demonstrated that dendritic cells (DCs) pulsed ex vivo with Toxoplasma gondii antigens trigger a systemic Th1-biased specific immune response and induce a protective and specific anti-toxoplasma immunity. In the present study, we demonstrate that tumor antigen pulsed DCs matured in the presence of Toxoplasma gondii components induce a potent anti-tumor response in a mouse model of fibrosarcoma. Bone-marrow derived DCs (BMDCs) were cultured in the presence of GM-CSF and IL-4. After 5 days, tumor lysates with/without T. gondii lysate were added to the culture for another 2 days. Cytokine production in BMDC culture and co culture supernatant of DC and splenic cells was evaluated. For immunization, 7 days after tumor challenge, different groups of Balb/c mice received different kinds of dendritic cells subcutaneously (S.C.) around the tumor site. Tumor growth was monitored and two weeks after DC immunotherapy cytotoxic activity and infiltration of CD8+ T cell monitored in different groups. According to the findings immunotherapy with T.gondii matured dendritic cells led to a significant increase in activity of cytotoxic T cells and decreased tumor growth of immunized animals. Immature DCs didn't cause any change in cytotoxic activity and tumor growth rate compare to normal or controls. The current study suggests that specific anti-tumor immune response can be induced by DCs matured with T.gondii component and provide the basis for the use of T.gondii in DC-targeted clinical therapies.
PMID: 19656994 [PubMed - as supplied by publisher]
Sunday, August 02, 2009
Apoptosis and S phase of the Cell Cycle in BeWo Trophoblastic and HeLa Cells is Differentially Modulated by Toxoplasma strain types
Placenta. 2009 Jul 28. [Epub ahead of print]
Apoptosis and S phase of the Cell Cycle in BeWo Trophoblastic and HeLa Cells is Differentially Modulated by Toxoplasma gondii Strain Types
Angeloni MB, Silva NM, Castro AS, Gomes AO, Silva DA, Mineo JR, Ferro EA.
Laboratory of Histology and Embriology, Institute of Biomedical Sciences, Universidade Federal de Uberlândia, Av. Pará 1720, 38400 902 Uberlândia, MG, Brazil.
Transplacental transmission of Toxoplasma gondii causes congenital toxoplasmosis, one of the most severe forms of infection. The ability of the parasite to survive intracellularly largely depends on the blocking of different proapoptotic signaling cascades of the host cells. During pregnancy, however, alterations in the incidence of apoptosis are associated with abnormal placental morphology and function. The aim of this study was to evaluate the incidence of apoptosis and cell proliferation in trophoblastic (BeWo cell line) and uterine cervical (HeLa cell line) cells infected with a highly virulent RH strain or a moderately virulent ME49 strain of T. gondii. BeWo and HeLa cells were infected with RH or ME49 tachyzoites (2:1 and 5:1; parasite:cell) or medium alone (control). After 2h, 6h and 12h of incubation, cells were fixed in 10% formalin and analyzed by immunohistochemistry to determine the apoptosis (expression of cytokeratin 18 neo-epitope - clone M30) and cell in S phase (expression of proliferating cell nuclear antigen - PCNA) indices. RH strain-infected BeWo and HeLa cells showed a lower apoptosis index than non-infected controls, whereas a higher apoptosis index was found in ME49 strain-infected cells compared to controls. In addition, RH-infected cells displayed lower apoptosis index than ME49-infected cells, even though active caspase-3 was detected in both cell types infected with either RH or ME49 strains as well in non-infected cells in all analyzed times of infection. Also, the cell S phase indices were higher in ME49 strain-infected BeWo and HeLa cells as compared to non-infected controls and RH strain-infected cells. These results indicate that RH and ME49 strains of T. gondii possess opposing mechanism of interference in apoptosis and cell cycle S phase of both BeWo and HeLa cells and these differences can be associated to evasion strategies of the parasite to survive inside the host cells.
PMID: 19643475 [PubMed - as supplied by publisher]
Apoptosis and S phase of the Cell Cycle in BeWo Trophoblastic and HeLa Cells is Differentially Modulated by Toxoplasma gondii Strain Types
Angeloni MB, Silva NM, Castro AS, Gomes AO, Silva DA, Mineo JR, Ferro EA.
Laboratory of Histology and Embriology, Institute of Biomedical Sciences, Universidade Federal de Uberlândia, Av. Pará 1720, 38400 902 Uberlândia, MG, Brazil.
Transplacental transmission of Toxoplasma gondii causes congenital toxoplasmosis, one of the most severe forms of infection. The ability of the parasite to survive intracellularly largely depends on the blocking of different proapoptotic signaling cascades of the host cells. During pregnancy, however, alterations in the incidence of apoptosis are associated with abnormal placental morphology and function. The aim of this study was to evaluate the incidence of apoptosis and cell proliferation in trophoblastic (BeWo cell line) and uterine cervical (HeLa cell line) cells infected with a highly virulent RH strain or a moderately virulent ME49 strain of T. gondii. BeWo and HeLa cells were infected with RH or ME49 tachyzoites (2:1 and 5:1; parasite:cell) or medium alone (control). After 2h, 6h and 12h of incubation, cells were fixed in 10% formalin and analyzed by immunohistochemistry to determine the apoptosis (expression of cytokeratin 18 neo-epitope - clone M30) and cell in S phase (expression of proliferating cell nuclear antigen - PCNA) indices. RH strain-infected BeWo and HeLa cells showed a lower apoptosis index than non-infected controls, whereas a higher apoptosis index was found in ME49 strain-infected cells compared to controls. In addition, RH-infected cells displayed lower apoptosis index than ME49-infected cells, even though active caspase-3 was detected in both cell types infected with either RH or ME49 strains as well in non-infected cells in all analyzed times of infection. Also, the cell S phase indices were higher in ME49 strain-infected BeWo and HeLa cells as compared to non-infected controls and RH strain-infected cells. These results indicate that RH and ME49 strains of T. gondii possess opposing mechanism of interference in apoptosis and cell cycle S phase of both BeWo and HeLa cells and these differences can be associated to evasion strategies of the parasite to survive inside the host cells.
PMID: 19643475 [PubMed - as supplied by publisher]
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