Research on inner membrane complex protein 1: a novel nanovaccines against Toxoplasma gondii.

Toxoplasma gondii (T. gondii) is a globally prevalent zoonotic parasite causing severe health and economic impacts. Despite decades of research, no commercial vaccine provides comprehensive protection against both acute and chronic toxoplasmosis. DNA vaccines represent a promising strategy, but their application is hindered by low delivery efficiency and limited immunogenicity. Here, we developed and evaluated pVAX1-TgIMC1-loaded PLGA and chitosan (CS) nanospheres as potential vaccine candidates. Immunization studies in mice showed that pVAX1-TgIMC1/PLGA and pVAX1-TgIMC1/CS nanospheres induced robust humoral and cellular immune responses, significantly enhancing specific IgG levels and cytokine production IFN-γ and IL-17 compared to the naked DNA vaccine. Both nanospheres also promoted dendritic cell maturation and T-cell activation, resulting in reduced parasite burdens in cardiac tissues post-challenge. Notably, the PLGA nanospheres exhibited superior protection against acute toxoplasmosis, while CS nanospheres provided additional advantages in antigen stability and delivery. The nanospheres were non-toxic, as confirmed by biochemical markers and histopathological analysis. These findings highlight pVAX1-TgIMC1/PLGA and pVAX1-TgIMC1/CS nanospheres as promising candidates for T. gondii vaccine development, warranting further optimization and validation in broader animal models.