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An MHC class I immune evasion gene of Marek's disease virus
- Hearn, Cari, Preeyanon, Likit, Hunt, Henry D., York, Ian A.
- Virology 2015 v.475 pp. 88-95
- Mardivirus, chickens, endoplasmic reticulum, gene expression regulation, immune evasion, major histocompatibility complex, peptide transporters
- Marek’s Disease Virus (MDV) is a widespread α-herpesvirus of chickens that causes T cell tumors. Acute, but not latent, MDV infection has previously been shown to lead to downregulation of cell-surface MHC class I (Virology 282:198–205 (2001)), but the gene(s) involved have not been identified. Here we demonstrate that an MDV gene, MDV012, is capable of reducing surface expression of MHC class I on chicken cells. Co-expression of an MHC class I-binding peptide targeted to the endoplasmic reticulum (bypassing the requirement for the TAP peptide transporter) partially rescued MHC class I expression in the presence of MDV012, suggesting that MDV012 is a TAP-blocking MHC class I immune evasion protein. This is the first unique non-mammalian MHC class I immune evasion gene identified, and suggests that α-herpesviruses have conserved this function for at least 100 million years.