Immune response and protective effect against chronic Toxoplasma gondii infection induced by vaccination with a DNA vaccine encoding profilin.

ABSTRACT: Toxoplasma gondii is an obligate intracellular parasite that can infect almost all warm-blooded animals. T. gondii profilin (TgPF) plays a crucial role in parasite motility and host cell invasion, and has shown promise against toxoplasmosis. DNA vaccine was considered to elicit effective humoral and cell-mediated immunity against T. gondii infection. The objective of the present study was to evaluate the immunogenicity of TgPF in mice using a DNA vaccination strategy.A DNA vaccine (pVAX-PF) encoding TgPF gene was constructed and then was intramuscularly injected into mice with and without a plasmid encoding IL-15 (pVAX-IL-15). The immune responses in immunized Kunming mice including lymphocyte proliferation, levels of cytokines, antibody titers and T lymphocyte subclasses were analyzed. The protective efficacy against chronic T. gondii infection was observed at 4 weeks post-infection with the cyst-forming PRU strain of T. gondii (Genotype II).EitherpVAX-PF with or without pVAX-IL-15 could elicit higher level of IgG and IgG2a antibodies and produce strong cellular immune responses in the immunized mice. The brain cyst numbers in mice immunized with pVAX-PF?+?pVAX-IL-15 (1843?±?215.7) and pVAX-PF (1897?±?337.8) were reduced 40.82% and 39.08%, respectively, compared to that in mice received nothing (3114?±?168.8), and the differences were statistically significant (P??0.05].The present study indicated that TgPF could be a promising vaccine candidate against chronic toxoplasmosis, which can be further used to develop multi-epitope vaccine formulations in food-producing animals against T. gondii infection.

SUBMITTER: Gao Q 

PROVIDER: S-EPMC5842554 | biostudies-literature | 2018 Mar

REPOSITORIES: biostudies-literature