CD274 and infection: To determine the role that B7-H1 plays in the development of virus specific cytotoxic T-cell responses we infected B7-H1 wild-type (B7-H1WT) and B7-H1 knockout mice (B7-H1KO) with TMEV-OVA8 for 6 days to determine whether immune responses induced by infection can kill virus specific target cells in an in vivo CTL assay.