Major histocompatibility complex class I and class II antigen presentation of human immunodeficiency virus antigens (MHC class I and MHC class II (HLA class I and class II in humans))

Human immunodeficiency virus (HIV) proteins produced inside infected host cells are processed into peptide fragments that are presented on the cell surface by major histocompatibility complex (MHC) class I and class II molecules. MHC class I molecules display endogenously-synthesized (intracellular) HIV peptides to CD8^+^ cytotoxic T lymphocytes, which can then kill infected cells. MHC class II molecules present exogenous or autophagocytosed HIV antigens to CD4^+^ helper T cells, facilitating broader immune activation. HIV has evolved mechanisms (notably via its *Nef* protein) to impair both class I and II pathways, helping it evade immune detection and perpetuate infection. Modulating these pathways is central to vaccine and immunotherapy research but is not directly druggable in the sense of a typical pharmacological target. As such, this concept is best understood as a cardinal immune process rather than a singular molecular target.

Other names

MHC class I/II antigen presentationHIV antigen presentation by MHCHLA class I/II-mediated antigen presentation

Some antiviral therapies may enhance antigen presentation by upregulating MHC expression or improving antigen processing. Interferon-γ can increase MHC II expression.