Immunization with Toxoplasma gondii aspartic protease 3 increases survival time of infected mice.

Aspartic proteases in the Toxoplasma gondii, called TgASP1, 2, 3, and 5, play essential roles in the life cycle. In a previous study, we have demonstrated that TgASP1 is an antigen that prolongs survival time of infected mice. As an in-depth study, we have investigated the protective immunity of TgSAP3. A bioinformatic analysis was used to predict the linear B-cell epitopes and potential Th-cell epitopes on TgASP3, the results suggested that it has a large number of excellent epitopes. Mice were inoculated with a recombinant eukaryotic expression vector to evaluate the immune protection against an infection with the virulent RH strain of T. gondii. The enhanced immune response and increased survival time (up to 18days) were observed for vaccinated mice, showing that the TgASP3 antigen can provides partial protection.