MX2 and cytomegalovirus infection: Both MxA and MxB are highly upregulated by HCMV infection (73, 150) and it has recently been discovered that MxB overexpression inhibits replication of HSV-1, HSV-2, Kaposi's sarcoma-associated herpesvirus (KSHV), MCMV, and HCMV (151, 152).