HLA-DRA and infection: Interestingly, the same inhibitory phenotype was observed upon infection with HCMV mutants lacking the US2-6 or the US2-11 gene region (Figure 1D and E), that comprise the genes for pUS2 and pUS3, which degrade HLA-DRα and HLA-DMα (Tomazin et al., 1999) and block the assembly of HLA-DRα/β heterodimers (Hegde et al., 2002), respectively.