ST2−/− mice have deficiencies in type-1 CD4+ and CD8+ T-cell responses during viral infection36,37, however, we did not see decreased frequencies or numbers of IFN-γ+ T cells during infection, likely due do the limited role for adaptive immunity during acute primary C. difficile infection (Supplementary Fig. 8h, i)11,38,39. The gene discussed is CD8A; the disease is infection.