CD4+ CD25− FoxP3+ regulatory cells are the predominant responding regulatory T cells after human rotavirus infection or vaccination in gnotobiotic pigs

Summary The distribution and dynamic changes of CD4+ CD25+ FoxP3+ and CD4+ CD25− FoxP3+ regulatory T (Treg) cells induced by human rotavirus (HRV) infection and vaccination were examined in neonatal gnotobiotic pigs infected with virulent HRV (VirHRV) or vaccinated with attenuated HRV (AttHRV). Subsets of gnotobiotic pigs in the AttHRV and control groups were challenged with VirHRV at post‐inoculation day (PID) 28. We demonstrated that VirHRV infection or AttHRV vaccination reduced frequencies and numbers of tissue‐residing Treg cells, and decreased the frequencies of interleukin‐10 (IL‐10) and transforming growth factor‐β (TGF‐β) producing CD4+ CD25− Treg cells in ileum, spleen and blood at PID 28. The frequencies of IL‐10 and TGF‐β producing CD4+ CD25− Treg cells in all sites at PID 28 were significantly inversely correlated with the protection rate against VirHRV‐caused diarrhoea (r = −1, P