HLA class II histocompatibility antigen, DR alpha chain (HLA-DRA)

HLA class II histocompatibility antigen, DR alpha chain is the invariable alpha subunit of the HLA-DR receptor, a major histocompatibility complex class II molecule crucial for adaptive immunity. It binds peptides derived from exogenous and some endogenous proteins and displays them on the surface of antigen-presenting cells (such as B lymphocytes, dendritic cells, and macrophages) for recognition by CD4-positive T cells. The peptide binding region associates with a variable DR beta chain, allowing extensive isoform diversity. This receptor is fundamental for selection and activation of T-helper cells, antibody production, and macrophage activation. Dysregulated HLA-DRA function is associated with immune-mediated diseases, cancer immunology, infection response, and autoimmune conditions. Expression of HLA-DRA serves as a biomarker for tumor immunogenicity and predicts efficacy for certain immunotherapies. The molecule is found on chromosome 6p21.32 and is highly conserved with limited polymorphism in its alpha chain coding sequence.

Other names

HLA-DRAMHC class II antigen DRADRα (DR alpha)Major histocompatibility complex, class II, DR alpha chain

Drugs or molecules with mechanisms affecting this target include: - Modulation of antigen presentation to alter T cell activation or tolerance - Enhancement of immune recognition (e.g., boosting tumor antigen display for immunotherapy) - Downregulation or upregulation of HLA-DR for immunosuppression or activation