Affiliation:
1. Anhui Medical University
Abstract
Abstract
Toxoplasma gondii (T. gondii) is a zoonotic pathogen that can cause toxoplasmosis in humans and animals, which poses a significant health and socio-economic burden on society. It has been known that vaccines could provide an effective and long-term strategy to control the disease while reducing reliance and the side effects of chemical therapeutics, but there is no perfect vaccine available for toxoplasmosis. To develop a safe, effective and long-lasting vaccine against T. gondii infection remains essential for the control of the disease. Our recent findings indicated that the virulence of the mutant strain WH3 Δrop18 to mice was significantly reduced and no cysts were formed in the brain, indicating that WH3 Δrop18 might serve as the vaccine candidate. Here we assessed the immunoprotective efficacy of WH3 Δrop18 parasite as a live attenuated vaccine. The results showed that one hundred percent of mice vaccinated with WH3 Δrop18 survived when challenged with either virulent RH strain of type I and WH3 strain of type Chinese 1 or cyst-forming ME49 strain of type Ⅱ and WH6 strain of type Chinese 1 and in quite a few mice, no cysts were detectable in the brain tissues. Vaccination with the WH3 Δrop18 triggered a strong immune response, including significantly increased level of the pro-inflammatory cytokines IFN-γ, IL-12 and TNF-α, the anti-inflammatory cytokine IL-10 and the activation of CD4+ and CD8+ T-lymphocytes. In addition, Toxoplasma-specific total IgG antibodies and subclasses of IgG1 and IgG2a remained at high levels for 30 days and even 125 days post vaccination. Passive transfer of naive mice with sera from vaccinated mice conveyed the resistance of naive mice to T. gondii. Our results strongly indicate that vaccine of WH3 Δrop18 provide effective cellular and humoral immune protection against a wide range strains of Toxoplasma infections and it might be a promising live attenuated vaccine candidate.
Publisher
Research Square Platform LLC