Major histocompatibility complex class I (MHC?I) molecules present antigenic peptides to cytotoxic T cells to eliminate infected or cancerous cells. The transporter associated with antigen processing (TAP) shuttles proteasomally generated peptides into the ER for MHC?I loading. As central part of the peptide-loading complex (PLC), TAP is targeted by viral factors, which inhibit peptide supply and thereby impact MHC?I-mediated immune responses. However, it is still poorly understood how antigen presentation via different MHC?I allotypes is affected by TAP inhibition. Here, we show that conditional expression of herpes simplex viral ICP47 suppresses surface presentation of HLA-A and HLA-C, but not of HLA-B, while the human cytomegaloviral US6 reduces surface levels of all MHC?I allotypes. This marked difference in HLA-B antigen presentation is echoed by an enrichment of HLA-B allomorphs at US6-arrested PLC in comparison to ICP47-PLC. Although both viral factors prevent TAP-mediated peptide supply, our data imply that MHC?I allomorphs favor different conformationally arrested states of the PLC, leading to differential downregulation of MHC?I surface presentation. These findings will help understand MHC?I biology in general and will even advance the targeted treatment of infections depending on patients' allotypes.