Human leukocyte antigen class I molecule, peptide-loaded (HLA-I (peptide-loaded))

Cytomegalovirus peptide-loaded HLA molecules are human class I major histocompatibility complex (MHC or HLA) proteins in which viral antigenic peptides derived from CMV are bound in the HLA peptide-binding groove and presented on the cell surface. This peptide/HLA complex is recognized by CD8+ T cells which can then mount a cytotoxic response to infected cells. HLA molecules involved include classical (HLA-A, -B, -C) and non-classical forms (HLA-E, -G); some cytomegalovirus proteins (UL40, for example) can supply peptides needed for HLA-E stabilization and NK cell modulation. CMV employs various immune evasion proteins (e.g., US2, US10) that interfere with HLA class I maturation, peptide loading, or cell-surface expression to evade immune detection. Peptide-loaded HLA complexes are critical for viral immune surveillance, but not a single gene product: they are functional complexes, with properties determined by both the HLA allele and the specific bound viral peptide. This entry does not refer to a single protein or gene but rather a class of molecular complexes (various HLA-I proteins bound to cytomegalovirus-derived peptides). This is functionally meaningful and often studied as a therapeutic or diagnostic "target," but it lacks a standardized canonical gene/protein symbol and covers a heterogeneous group of peptide/MHC complexes.

Other names

Major histocompatibility complex class I, peptide-loadedHLA class I, peptide/MHC complexHuman MHC class I, peptide-presenting formSpecific HLA-I molecules can include HLA-A, HLA-B, HLA-C, HLA-E, HLA-G, etc., each loaded with a cytomegalovirus-derived peptide

Presentation of viral (CMV) peptide antigens to CD8+ T cells; Stimulation or inhibition of immune effector cells (T cells, NK cells) depending on peptide and HLA allotype