Toxoplasma gondii virus-like particle vaccination alleviates inflammatory response in the brain upon T gondii infection

Aims: Neuroinflammation can manifest upon infection with the neurotropic parasite Toxoplasma gondii (ME49), which can lead to brain injury and cognitive dysfunction. Rhoptry organelle proteins (ROPs) secreted by T gondii play critical roles in host invasion. Methods and results: In this study, influenza virus-like particles (VLPs) expressing T gondii ROP4 or ROP13 were generated to assess vaccination-induced changes in intracranial pro-inflammatory cytokines and antibody responses upon T gondii challenge infection. Compared to ROP13 VLPs, ROP4VLPs vaccination significantly limited the production of pro-inflammatory cytokines IFN-γ and IL-6 in the brains of mice. Reduced pro-inflammatory cytokine responses by ROP4 VLPs and ROP13 VLPs correlated with significantly increased T gondii-specific IgG and IgA antibody responses in the brain, as well as IgG, IgG1 and IgM antibody responses in the sera. Conclusion: We concluded that influenza T gondii VLP vaccination induces antibody responses in sera and brain, which may contribute to the significant reduction of neuroinflammation during T gondii infection.