Protection and Immune Responses Elicited by rSAG۱-PLGA Nanoparticles in C۵۷BL/۶ Against Toxoplasma gondii

Introduction: This study aimed to evaluate rSAG۱-PLGA efficacy as a particulate vaccine in conferring protection against Toxoplasma gondii infection in C۵۷BL/۶ mice. In light of our previous studies, we studied mice genotype role in eliciting immune responses by rSAG۱-PLGA nanoparticles in this study. Methods: Poly (DL-lactide-co-glycolide) (PLGA) nanoparticles loaded by rSAG۱ as a subunit vaccine were prepared, and C۵۷BL/۶ mice were subcutaneously immunized twice at a ۳-week interval by rSAG۱-PLGA, soluble rSAG۱, blank PLGA, and one group kept unvaccinated. The characteristics of PLGA nanoparticles, the amounts of produced IFN-γ, IL-۱۰, specific anti-ToxoplasmaIgGs, and the conferred protection against infection by T. gondii RH tachyzoite were assessed. Results: rSAG۱-PLGA nanoparticles shared a z-average of about ۴۵۰nm with negative Zeta potential. Compared with the negative control group, the mice vaccinated with rSAG۱-PLGA nanoparticles produced significantly higher amounts of IFN-γ, specific anti-T. gondii IgG antibodies and higher titer of IgG۲a, which resulted in longer survival times. Conclusion: The efficiency of rSAG۱-PLGA nanoparticles in inducing humoral and cellular responses and consequently partial protection against acute toxoplasmosis in C۵۷BL/۶ was confirmed.

Keywords:

: rSAG۱-PLGA , Toxoplasma gondii , vaccine , C۵۷BL/۶ , nanoparticles