Human leukocyte antigen class I histocompatibility antigen, A alpha chain (HLA-A*02)

Human leukocyte antigen class I histocompatibility antigen, A alpha chain—commonly referred to as "HLA-A" with the specific allele "A*02"—is a transmembrane glycoprotein encoded within the major histocompatibility complex on chromosome 6. As an MHC class I molecule, it is expressed on nearly all nucleated human cells and functions primarily to present endogenous peptides—including those derived from viruses or tumors—to CD8+ cytotoxic T lymphocytes. This process enables immune surveillance against infected or malignant cells by triggering their destruction upon recognition of non-self peptides. The extreme polymorphism at the HLA loci—including over 300 allelic variants for HLA-A2 alone—contributes both to individual variability in disease susceptibility/protection and challenges in organ transplantation due to alloimmune responses. The presence/absence of specific alleles such as HLA-A*02 can influence outcomes in infections like hepatitis B/C and various cancers. While not directly targeted by conventional drugs, its role is central in modern immunotherapeutic strategies where patient selection often depends on their expression of particular alleles like HLA-A*02. Safety considerations revolve around its critical role in self/non-self discrimination—a double-edged sword relevant both for effective immunity and risk for autoimmunity/alloreactivity.

Other names

HLA-A2HLA-A*02HLA class I histocompatibility antigen, A alpha chainMHC class I A*02

Drugs or biologics that interact with this molecule typically function by presenting tumor-associated or viral peptides to CD8+ cytotoxic T lymphocytes, leading to targeted immune-mediated killing, or by modulating immune response via engineered immune cells recognizing specific peptide-HLA complexes.