Major histocompatibility complex, class II, DR (HLA-DR) (HLA-DR)

Major histocompatibility complex, class II, DR (HLA-DR) is a cell surface receptor belonging to the major histocompatibility complex (MHC) class II family, encoded by genes in the human leukocyte antigen (HLA) complex on chromosome 6[1][3]. HLA-DR functions as a heterodimer composed of alpha and beta chains and is predominantly expressed on antigen-presenting cells such as B cells, dendritic cells, and macrophages[1][3][7]. Its primary biological function is to present extracellular peptide antigens to CD4+ T helper cells, thereby initiating and regulating the adaptive immune response[1][3]. HLA-DR plays a pivotal role in transplantation immunology, as matching and mismatching particular HLA-DR alleles can determine graft survival or rejection[1]. It is also a key biomarker for immune activation and is frequently implicated in the genetic susceptibility to autoimmune diseases, infectious diseases, and various immune-mediated conditions[5][3]. Therapeutic agents that modulate antigen presentation and T-cell responses often target pathways associated with HLA-DR to treat autoimmune diseases, prevent organ rejection, or modulate unwanted immune responses. Notable challenges with therapies targeting the HLA-DR pathway include increased susceptibility to infections and the potential for triggering or exacerbating autoimmune conditions[1][3].

Other names

Human leukocyte antigen – DR isotypeHLA-DR antigenHLA class II histocompatibility antigen, DR beta chainHLA-DR1BHLA-DRBDRB1MHC class II HLA-DR beta 1 chainMHC class II HLA-DR-beta cell surface glycoproteinDR proteinlymphocyte antigen DRB1

Inhibition of antigen presentation to T cells Suppression of T helper cell activation Reduction of immune-mediated graft rejection