RPS3 and infection: MSR3 appeared refractory to infection by commonly available HCMV strains (i.e., AD169, Towne, TB40/E) (not shown) but was permissive to a strain derived from a clinical isolate (UL1271) (Figure 1A) available as a recombinant BACmid clone (AB8) [41], in which US2, US3 and US6 genes are deleted, thus reducing HLA‐I downregulation in infected cells as previously shown for the AD169 strain BAC (HB5) [52].