Vaccination with a DNA vaccine coding Perforin-like Protein 1 (TgPLP1) and MIC6 Induces Significant Protective Immunity Against Toxoplasma

Clin Vaccine Immunol. 2012 Feb 29. [Epub ahead of print]

Vaccination with a DNA vaccine coding Perforin-like Protein 1 (TgPLP1) and MIC6 Induces Significant Protective Immunity Against Toxoplasma gondii.

Yan HK, Yuan ZG, Song HQ, Petersen E, Zhou Y, Ren D, Zhou DH, Li HX, Lin RQ, Yang GL, Zhu XQ.

Source
State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, CAAS, Lanzhou, Gansu Province 730046, People's Republic of China.

Abstract
Host cell invasion by Toxoplasma gondii is tightly related to micronemal protein 6 (MIC6) and T. gondii perforin-like protein 1 (TgPLP1). In this study, we constructed a DNA vaccine expressing a fusion protein of TgPLP1/MIC6 using vector pIRESneo, and evaluated the immune response it induced in Kunming mice. Levels of IgG antibody, IFN-γ, IL-2, IL-12, IL-4 and IL-10 were examined. Five mice were randomly chosen from every group (vaccinated or non-vaccinated control groups) and were intragastrically challenged with 80 cysts of the T. gondii PRU strain (genotype II) strain to observe mortality daily. To analyze protection against less virulent challenge, eight mice of each group were orally infected with 20 cysts of the PRU strain at the 14th day after the last immunization. The brain parasite load was evaluated 6 weeks after infection. The results demonstrated that the immunization with pIRESneo/MIC6/PLP1 resulted in the lowest brain cyst count and prolonged the survival time of immunized mice. The levels of Toxoplasma-specific IgG, IFN-γ, IL-2 and IL-12 increased significantly, and the cysts in brains decreased more obviously in the group immunized with the plasmid pIRESneo/MIC6/PLP1 than the other groups (P < 0.05). Compared with pIRESneo/MIC6/PLP1, co-immunization of pIRESneo/MIC6/PLP1 with adjuvant murine IL-18 promoted cellular and humoral immune responses, but did not contribute significantly in cyst reduction (65.43% vs 61.60%) or survival of immunized mice (45.0 ± 2.9 days vs 42.8 ± 2.9 days) (P > 0.05). Furthermore, the study also showed that immune efficacy induced by pIRESneo/MIC6/PLP1 was better than that induced by pVAX/PLP1 or pVAX/MIC6 alone.


PMID: 22379063 [PubMed - as supplied by publisher]