P04439 

HLA-A belongs to the HLA class I heavy chain paralogues. HLA-A plays a crucial role in the immune response by presenting peptide antigens to T lymphocytes, which is essential for the activation of adaptive immunity. Located on the surface of nearly all nucleated cells, HLA-A molecules are vital for the recognition of infected or malignant cells by cytotoxic T cells, thereby facilitating the elimination of these cells from the body. The structure of HLA-A consists of a membrane-anchored heavy chain that forms a heterodimer with beta-2-microglobulin, allowing for presentation of peptides derived from intracellular proteins. The polymorphic nature of HLA-A, with hundreds of alleles identified, contributes to the diversity of immune responses among individuals, making HLA-A a key factor in transplantation compatibility and susceptibility to autoimmune diseases.