Major histocompatibility complex class I (MHC-I)

The Major histocompatibility complex class I (MHC-I) peptide-binding groove is a specialized structural domain formed by the alpha-1 and alpha-2 subunits of the MHC-I heavy chain (UniProt: P01889). Its primary biological function is to capture and display short peptides, typically 8-10 amino acids in length, derived from intracellular proteins on the cell surface for surveillance by CD8+ cytotoxic T lymphocytes (StatPearls: NBK542216). In healthy cells, these peptides represent "self," but in the context of viral infection or malignancy, the groove presents "non-self" or "neoantigen" peptides that trigger an immune response (PubMed: 22722203). This site is a critical therapeutic target for cancer immunotherapies, including T-cell receptor (TCR)-based therapies like Tebentafusp and various peptide vaccines, which aim to enhance the recognition of tumor-specific antigens (PubMed: 34551229). Additionally, certain drugs like abacavir can bind within the groove of specific alleles (e.g., HLA-B*57:01), altering the repertoire of presented peptides and leading to severe hypersensitivity reactions (PubMed: 22608002). The high degree of polymorphism in the MHC-I groove across the human population presents a significant challenge for drug development, requiring precise HLA typing for patient selection (PubMed: 22608005). Understanding the specificity of the MHC-I groove is essential for developing precision medicines that can distinguish between healthy and diseased tissues while avoiding off-target autoimmune effects (PubMed: 31434692).

Other names

HLA class IHuman leukocyte antigen class IMHC-I peptide-binding cleftMHC-I groove

Presentation of intracellularly derived peptides to CD8+ T-cell receptors (TCRs) to initiate an immune response; direct binding by small molecules or engineered TCRs to modulate or trigger immune recognition.