Viral peptide-HLA complex

The **viral peptide–HLA complex** refers to a molecular complex formed when a fragment of a viral protein (peptide) is bound within the peptide-binding groove of a human leukocyte antigen (HLA) molecule, typically a class I or class II MHC molecule, on the surface of an infected cell[1][3][4][6]. These complexes are central to the adaptive immune system—they present viral peptides at the cell surface, allowing recognition by T-cell receptors (TCRs) on cytotoxic T lymphocytes, which can then target and destroy infected cells[4][6][7]. The structure consists of an HLA heavy chain, a β2-microglobulin subunit, and a bound peptide, usually 8–10 amino acids in the case of class I, or longer for class II complexes[1][4][5]. The specificity of TCR-mediated immune response depends on both the peptide and the presenting HLA allele[6]. Because these complexes are not a unique gene or protein, but a transient, diverse molecular combination, "viral peptide–HLA complexes on infected cells" is a conceptual therapeutic target rather than a named, standardized protein; thus, is_incorrect is set to true in this context.

Other names

Peptide–MHC complexPeptide–HLA complexAntigen–HLA complexpMHC complex

Activation of T-cell receptor (TCR) through cell-surface antigen presentation - Immune checkpoint modulation (for drugs like pembrolizumab and nivolumab, which indirectly depend on pMHC–TCR interactions)