FUT1 and infection: Because it is difficult to detect even wild-type MCMV beyond the first few weeks after infection in vivo in mice (37, 38), we studied the immune response to well-characterized H-2d–restricted MCMV antigenic epitopes to determine whether the attenuated eMCMV or MCMV85A viruses persist in vivo and generate immune responses characteristic of other MCMVs.