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Background: The threat of Toxoplasma gondii infection in immunocompromised individuals and pregnant women necessitates the development of a safe and effective vaccine. Here, we examined the immune protection conferred by a live attenuated strain of T. gondii.Methods: We tested the efficacy of intraperitoneal vaccination using 500 Ca2+-dependent protein kinase 2 (cdpk2)-deficient tachyzoites of T. gondii Pru strain against acute, chronic, and congenital toxoplasmosis in mice. The kinetics of antibody response, cytokines, and other quantifiable correlates of protection against T. gondii infection were determined.Results: Vaccination with Pru:Δcdpk2 induced a high level of anti-T. gondii immunoglobulin G titer, type 1 T-helper (Th1) response at 28 days postvaccination, and a mixed Th1/type 2 T-helper response at 70 days postvaccination. All vaccinated mice survived a heterologous challenge with 1000 tachyzoites of RH or ToxoDB#9 (PYS or TgC7) strains. Also, vaccination protected against homologous infection with 20 T. gondii Pru cysts, and improved pregnancy outcome by reducing parasite cyst load in the brain, maintaining litter size and body weight of pups born to vaccinated dams challenged with 10 Pru cysts compared to pups born to unvaccinated dams.Conclusions: The use of T. gondii Pru:Δcdpk2 mutant strain represents a promising approach to protection against acute, chronic, and congenital toxoplasmosis in mice. [ABSTRACT FROM AUTHOR]

Toxoplasma gondii is an intracellular zoonotic parasite that causes toxoplasmosis, which can cause economic losses and serious public health problems worldwide. A member of the T. gondii calcium-dependent protein kinases family, TgCDPK1 was recently identified as an essential regulator of exocytosis in T. gondii, and participated in direct parasite motility, host-cell invasion and egress. In the present study, the protective immunity of recombinant TgCDPK1 protein (rTgCDPK1) was evaluated against acute toxoplasmosis in mice. rTgCDPK1 were expressed and purified, BABL/c mice were intraperitoneally immunized with rTgCDPK1 and challenged with the highly virulent RH strain of T. gondii. The specific immune responses were analyzed by measuring the cytokine and serum antibody, and lymphocyte proliferation assays, flow cytometry of lymphocytes and the survival curve were employed to evaluate the protective efficacy. From the results we found that special humoral and cellular responses could be elicited in vaccine mice, and higher level of IgG antibody, and the significant increased levels of Th1-type cytokines IFN-γ, IL-12 (p70), IL10 and CD3+CD4+CD8− and CD3+CD8+CD4− T cells could also be detected comparing to control mice (P < 0.05). All vaccinated mice prolonged survival time (14.90 ± 2.89 days) challenge with 1000 tachyzoites of RH, while the control mice died within 8 days. These results indicated that TgCDPK1 protein was a potential vaccine candidate against acute toxoplasmosis. • The rTgCDPK1 could elicited special humoral and cellular responses in vaccine mice. • All vaccinated mice prolonged survival time challenge with tachyzoites of RH. • TgCDPK1 protein is a potential vaccine candidate against acute toxoplasmosis. [ABSTRACT FROM AUTHOR]