Human immunodeficiency virus Nef peptide–Major Histocompatibility Complex class I complex (HIV Nef-MHC I complex)

The HIV Nef peptide–Major Histocompatibility Complex (MHC) class I complex is a molecular assembly consisting of a peptide fragment derived from the HIV Nef protein bound to the peptide-binding groove of an MHC class I molecule. Nef is a critical 27-35 kDa accessory protein of HIV-1 and HIV-2 that is essential for viral pathogenesis and immune evasion (UniProt P03406). One of its primary roles is the downregulation of surface MHC-I molecules (specifically HLA-A and HLA-B) to shield infected cells from detection by cytotoxic T lymphocytes (PubMed: 15944439). Despite this downregulation, specific Nef-derived peptides are still processed and presented on the cell surface, serving as highly specific markers for HIV-infected cells. These complexes are currently being targeted by novel immunotherapeutic strategies, such as TCR-engineered T cells and bispecific T-cell engagers, which aim to bypass viral evasion mechanisms and eliminate the latent HIV reservoir (PubMed: 30249038). The therapeutic utility of this target depends on the high specificity of the T-cell receptor for the viral peptide-MHC complex to avoid cross-reactivity with human self-antigens.

Other names

Nef-HLA complexHIV-1 Nef peptide-HLA-A*02 complexNef-MHC-IpMHC (Nef)

Recognition of the specific Nef peptide presented within the MHC-I groove by engineered or endogenous T-cell receptors (TCRs) or TCR-mimetic antibodies, which triggers the cytotoxic activity of T cells to lyse HIV-infected cells.