An HLA-A2-Restricted T-Cell Epitope Mapped to the BNLF2a Immune Evasion Protein of Epstein-Barr Virus That Inhibits TAP

摘要

The early lytic cycle protein of Epstein-Barr virus (EBV), BNLF2a, has recently been shown to play a critical role in immune evasion by inhibiting the peptide transporter associated with antigen processing (TAP), thereby blocking antigen-specific CD8⁺ T-cell recognition of many lytic cycle antigens. Surprisingly, we now show that a peptide (⁵⁰VLFGLLCLL⁵⁸) from the hydrophobic C-terminal region of this small (60-amino-acid) EBV protein is efficiently presented by the common class I allele HLA-A2 for recognition by cytotoxic T lymphocytes. The mechanism for this unexpected finding was revealed by experiments showing that this epitope is processed and presented independently of TAP.