HLA-DR

MHC class II, DR
(heterodimer)
Illustration of DR with bound ligand (yellow)
Protein typecell surface receptor
FunctionImmune recognition and
antigen presentation
Subunit name Gene Chromosomal locus
α HLA-DRA Chromosome 6p21.31
β1 HLA-DRB1 " "
β3 HLA-DRB3 " "
β4 HLA-DRB4 " "
β5 HLA-DRB5 " "

HLA-DR is an MHC class II cell surface receptor encoded by the human leukocyte antigen complex on chromosome 6 region 6p21.31. The complex of HLA-DR (Human Leukocyte Antigen – DR isotype) and peptide, generally between 9 and 30 amino acids in length, constitutes a ligand for the T-cell receptor (TCR). HLA (human leukocyte antigens) were originally defined as cell surface antigens that mediate graft-versus-host disease. Identification of these antigens has led to greater success and longevity in organ transplant.

Antigens most responsible for graft loss are HLA-DR (first six months), HLA-B (first two years), and HLA-A (long-term survival).[1] Good matching of these antigens between host and donor is most critical for achieving graft survival.

HLA-DR is also involved in several autoimmune conditions, disease susceptibility and disease resistance. It is also closely linked to HLA-DQ and this linkage often makes it difficult to resolve the more causative factor in disease.

HLA-DR molecules are upregulated in response to signalling. In the instance of an infection, the peptide (such as the staphylococcal enterotoxin I peptide) is bound into a DR molecule and presented to a few of a great many T-cell receptors found on T-helper cells. These cells then bind to antigens on the surface of B-cells stimulating B-cell proliferation.

  1. ^ Solomon S, Pitossi F, Rao MS (2015). "Banking on iPSC--is it doable and is it worthwhile". Stem Cell Reviews. 11 (1): 1–10. doi:10.1007/s12015-014-9574-4. PMC 4333229. PMID 25516409.