Virus-specific intestinal IFN-γ producing T cell responses induced by human rotavirus infection and vaccines are correlated with protection against rotavirus diarrhea in gnotobiotic pigs

We examined rotavirus-specific IFN-γ producing CD4+, CD8+ and CD4+CD8+ T cell responses in gnotobiotic pigs infected with a virulent human rotavirus (VirHRV) or vaccinated with an attenuated (Att) HRV vaccine (AttHRV3x or AttHRV2x) or an AttHRV oral priming and 2/6-virus-like particle (VLP) intranasal boosting (AttHRV-2/6VLP) regimen. In VirHRV infected pigs, HRV-specific IFN-γ producing T cells reside primarily in ileum. AttHRV-2/6VLP induced similar frequencies of intestinal IFN-γ producing T cells as the VirHRV, whereas AttHRV3x or 2x vaccines were less effective. Protection rates against rotavirus diarrhea upon VirHRV challenge significantly correlated (r = 0.97–1.0, p < 0.005) with frequencies of intestinal IFN-γ producing T cells, suggesting their role in protective immunity.