HLA-DRB1

HLA-DRB1 belongs to the HLA class II beta chain paralogs. The class II molecule is a heterodimer consisting of an alpha (DRA) and a beta chain (DRB), both anchored in the membrane. It plays a central role in the immune system by presenting peptides derived from extracellular proteins. Class II molecules are expressed in antigen presenting cells (APC: B lymphocytes, dendritic cells, macrophages). The beta chain is approximately 26-28 kDa. It is encoded by 6 exons. Exon one encodes the leader peptide; exons 2 and 3 encode the two extracellular domains; exon 4 encodes the transmembrane domain; and exon 5 encodes the cytoplasmic tail. Within the DR molecule the beta chain contains all the polymorphisms specifying the peptide binding specificities. Hundreds of DRB1 alleles have been described and typing for these polymorphisms is routinely done for bone marrow and kidney transplantation. DRB1 is expressed at a level five times higher than its paralogs DRB3, DRB4 and DRB5. DRB1 is present in all individuals. Allelic variants of DRB1 are linked with either none or one of the genes DRB3, DRB4 and DRB5. There are 4 related pseudogenes: DRB2, DRB6, DRB7, DRB8 and DRB9.

HLA-DRB1

A beta chain of antigen-presenting major histocompatibility complex class II (MHCII) molecule. In complex with the alpha chain HLA-DRA, displays antigenic peptides on professional antigen presenting cells (APCs) for recognition by alpha-beta T cell receptor (TCR) on HLA-DRB1-restricted CD4-positive T cells. This guides antigen-specific T-helper effector functions, both antibody-mediated immune response and macrophage activation, to ultimately eliminate the infectious agents and transformed cells (PubMed:29884618, PubMed:22327072, PubMed:27591323, PubMed:8642306, PubMed:15265931, PubMed:31495665, PubMed:16148104).

Typically presents extracellular peptide antigens of 10 to 30 amino acids that arise from proteolysis of endocytosed antigens in lysosomes (PubMed:8145819).

In the tumor microenvironment, presents antigenic peptides that are primarily generated in tumor-resident APCs likely via phagocytosis of apoptotic tumor cells or macropinocytosis of secreted tumor proteins (PubMed:31495665).

Presents peptides derived from intracellular proteins that are trapped in autolysosomes after macroautophagy, a mechanism especially relevant for T cell selection in the thymus and central immune tolerance (PubMed:17182262, PubMed:23783831).

The selection of the immunodominant epitopes follows two processing modes: 'bind first, cut/trim later' for pathogen-derived antigenic peptides and 'cut first, bind later' for autoantigens/self-peptides (PubMed:25413013).

The anchor residue at position 1 of the peptide N-terminus, usually a large hydrophobic residue, is essential for high affinity interaction with MHCII molecules (PubMed:8145819).

Allele DRB1*01:01: Displays an immunodominant epitope derived from Bacillus anthracis pagA/protective antigen, PA (KLPLYISNPNYKVNVYAVT), to both naive and PA-specific memory CD4-positive T cells (PubMed:22327072).

Presents immunodominant HIV-1 gag peptide (FRDYVDRFYKTLRAEQASQE) on infected dendritic cells for recognition by TRAV24-TRBV2 TCR on CD4-positive T cells and controls viral load (PubMed:29884618).

May present to T-helper 1 cells several HRV-16 epitopes derived from capsid proteins VP1 (PRFSLPFLSIASAYYMFYDG) and VP2 (PHQFINLRSNNSATLIVPYV), contributing to viral clearance (PubMed:27591323).

Displays commonly recognized peptides derived from IAV external protein HA (PKYVKQNTLKLAT and SNGNFIAPEYAYKIVK) and from internal proteins M, NP and PB1, with M-derived epitope (GLIYNRMGAVTTEV) being the most immunogenic (PubMed:8145819, PubMed:9075930, PubMed:25413013, PubMed:32668259).

Presents a self-peptide derived from COL4A3 (GWISLWKGFSF) to TCR (TRAV14 biased) on CD4-positive, FOXP3-positive regulatory T cells and mediates immune tolerance to self (PubMed:28467828).

May present peptides derived from oncofetal trophoblast glycoprotein TPBG 5T4, known to be recognized by both T-helper 1 and regulatory T cells (PubMed:31619516).

Displays with low affinity a self-peptide derived from MBP (VHFFKNIVTPRTP) (PubMed:9075930).

Allele DRB1*03:01: May present to T-helper 1 cells an HRV-16 epitope derived from capsid protein VP2 (NEKQPSDDNWLNFDGTLLGN), contributing to viral clearance (PubMed:27591323).

Displays self-peptides derived from retinal SAG (NRERRGIALDGKIKHE) and thyroid TG (LSSVVVDPSIRHFDV) (PubMed:25413013).

Presents viral epitopes derived from HHV-6B gH/U48 and U85 antigens to polyfunctional CD4-positive T cells with cytotoxic activity implicated in control of HHV-6B infection (PubMed:31020640).

Presents several immunogenic epitopes derived from C. tetani neurotoxin tetX, playing a role in immune recognition and long-term protection (PubMed:19830726).

Allele DRB1*04:01: Presents an immunodominant bacterial epitope derived from M. tuberculosis esxB/culture filtrate antigen CFP-10 (EISTNIRQAGVQYSR), eliciting CD4-positive T cell effector functions such as IFNG production and cytotoxic activity (PubMed:15265931).

May present to T-helper 1 cells an HRV-16 epitope derived from capsid protein VP2 (NEKQPSDDNWLNFDGTLLGN), contributing to viral clearance (PubMed:27591323).

Presents tumor epitopes derived from melanoma-associated TYR antigen (QNILLSNAPLGPQFP and DYSYLQDSDPDSFQD), triggering CD4-positive T cell effector functions such as GMCSF production (PubMed:8642306).

Displays preferentially citrullinated self-peptides derived from VIM (GVYATR/citSSAVR and SAVRAR/citSSVPGVR) and ACAN (VVLLVATEGR/ CitVRVNSAYQDK) (PubMed:24190431).

Displays self-peptides derived from COL2A1 (PubMed:9354468).

Allele DRB1*04:02: Displays native or citrullinated self-peptides derived from VIM.

Allele DRB1*04:04: May present to T-helper 1 cells several HRV-16 epitopes derived from capsid proteins VP1 (HIVMQYMYVPPGAPIPTTRN) and VP2 (RGDSTITSQDVANAVVGYGV), contributing to viral clearance (PubMed:27591323).

Displays preferentially citrullinated self-peptides derived from VIM (SAVRAR/citSSVPGVR) (PubMed:24190431).

Allele DRB1*04:05: May present to T-helper 1 cells an immunogenic epitope derived from tumor-associated antigen WT1 (KRYFKLSHLQMHSRKH), likely providing for effective antitumor immunity in a wide range of solid and hematological malignancies.

Allele DRB1*05:01: Presents an immunodominant HIV-1 gag peptide (FRDYVDRFYKTLRAEQASQE) on infected dendritic cells for recognition by TRAV24-TRBV2 TCR on CD4-positive T cells and controls viral load.

Allele DRB1*07:01: Upon EBV infection, presents latent antigen EBNA2 peptide (PRSPTVFYNIPPMPLPPSQL) to CD4-positive T cells, driving oligoclonal expansion and selection of a dominant virus-specific memory T cell subset with cytotoxic potential to directly eliminate virus-infected B cells (PubMed:31308093).

May present to T-helper 1 cells several HRV-16 epitopes derived from capsid proteins VP1 (PRFSLPFLSIASAYYMFYDG) and VP2 (VPYVNAVPMDSMVRHNNWSL), contributing to viral clearance (PubMed:27591323).

In the context of tumor immunesurveillance, may present to T-helper 1 cells an immunogenic epitope derived from tumor-associated antigen WT1 (MTEYKLVVVGAVGVGKSALTIQLI), likely providing for effective antitumor immunity in a wide range of solid and hematological malignancies (PubMed:22929521).

In metastatic epithelial tumors, presents to intratumoral CD4-positive T cells a KRAS neoantigen (MTEYKLVVVGAVGVGKSALTIQLI) carrying G12V hotspot driver mutation and may mediate tumor regression (PubMed:30282837).

Allele DRB1*11:01: Displays an immunodominant HIV-1 gag peptide (FRDYVDRFYKTLRAEQASQE) on infected dendritic cells for recognition by TRAV24-TRBV2 TCR on CD4-positive T cells and controls viral load (PubMed:29884618).

May present to T-helper 1 cells an HRV-16 epitope derived from capsid protein VP2 (SDRIIQITRGDSTITSQDVA), contributing to viral clearance (PubMed:27591323).

Presents several immunogenic epitopes derived from C. tetani neurotoxin tetX, playing a role in immune recognition and longterm protection (PubMed:19830726).

In the context of tumor immunesurveillance, may present tumor-derived neoantigens to CD4-positive T cells and trigger anti-tumor helper functions (PubMed:31495665).

Allele DRB1*13:01: Presents viral epitopes derived from HHV-6B antigens to polyfunctional CD4-positive T cells implicated in control of HHV-6B infection.

Allele DRB1*15:01: May present to T-helper 1 cells an HRV-16 epitope derived from capsid protein VP2 (SNNSATLIVPYVNAVPMDSM), contributing to viral clearance (PubMed:27591323).

Displays a self-peptide derived from MBP (ENPVVHFFKNIVTPR) (PubMed:9782128, PubMed:25413013).

May present to T-helper 1 cells an immunogenic epitope derived from tumor-associated antigen WT1 (KRYFKLSHLQMHSRKH), likely providing for effective antitumor immunity in a wide range of solid and hematological malignancies.

Allele DRB1*15:02: Displays an immunodominant HIV-1 gag peptide (FRDYVDRFYKTLRAEQASQE) on infected dendritic cells for recognition by TRAV24-TRBV2 TCR on CD4-positive T cells and controls viral load (PubMed:29884618).

May present to T-helper 1 cells an immunogenic epitope derived from tumor-associated antigen WT1 (KRYFKLSHLQMHSRKH), likely providing for effective antitumor immunity in a wide range of solid and hematological malignancies (PubMed:19120973).

(Microbial infection) Acts as a receptor for Epstein-Barr virus on lymphocytes.

Antigen processing and presentation of endogenous peptide antigen via MHC class II Source: UniProtKB
Antigen processing and presentation of exogenous peptide antigen via MHC class II Source: UniProtKB
Detection of bacterium Source: UniProtKB
Epidermis development Source: UniProtKB
Humoral immune response Source: UniProtKB
Immune response Source: UniProtKB
Inflammatory response to antigenic stimulus Source: UniProtKB
Macrophage differentiation Source: ARUK-UCL
Myeloid dendritic cell antigen processing and presentation Source: UniProtKB
Negative regulation of inflammatory response to antigenic stimulus Source: UniProtKB
Negative regulation of interferon-gamma production Source: UniProtKB
Negative regulation of T cell proliferation Source: UniProtKB
Peptide antigen assembly with MHC class II protein complex Source: UniProtKB
Positive regulation of CD4-positive, alpha-beta T cell activation Source: UniProtKB
Positive regulation of CD4-positive, CD25-positive, alpha-beta regulatory T cell differentiation Source: UniProtKB
Positive regulation of ERK1 and ERK2 cascade Source: CAFA
Positive regulation of I-kappaB kinase/NF-kappaB signaling Source: CAFA
Positive regulation of insulin secretion involved in cellular response to glucose stimulus Source: UniProtKB
Positive regulation of kinase activity Source: CAFA
Positive regulation of MAPK cascade Source: CAFA
Positive regulation of memory T cell differentiation Source: UniProtKB
Positive regulation of monocyte differentiation Source: CAFA
Positive regulation of protein phosphorylation Source: CAFA
Positive regulation of T cell activation Source: GO_Central
Positive regulation of T cell mediated cytotoxicity Source: UniProtKB
Positive regulation of T cell mediated immune response to tumor cell Source: UniProtKB
Positive regulation of transcription, DNA-templated Source: CAFA
Positive regulation of viral entry into host cell Source: CAFA
Protein tetramerization Source: UniProtKB
Regulation of interleukin-10 production Source: UniProtKB
Regulation of interleukin-4 production Source: UniProtKB
Regulation of T-helper cell differentiation Source: UniProtKB
Signal transduction Source: UniProtKB
T cell receptor signaling pathway Source: UniProtKB
T-helper 1 type immune response Source: UniProtKB

Late endosome membrane; Lysosome membrane; Autolysosome membrane; Endoplasmic reticulum membrane; Cell membrane. The MHC class II complex transits through a number of intracellular compartments in the endocytic pathway until it reaches the cell membrane for antigen presentation (PubMed:18305173). Component of immunological synapses at the interface between T cell and APC (PubMed:29884618).

In populations of European descent, allele DRB1*01:03 is associated with increased susceptibility to Crohn disease and colonic ulcerative colitis. Decreased heterozygosity in individuals with colonic ulcerative colitis suggests that it acts as a recessive risk allele.
Sarcoidosis 1 (SS1):
Disease susceptibility is associated with variants affecting the gene represented in this entry. Alleles DRB1*04:02, DRB1*11:01 and DRB1*12:01 are associated with sarcoidosis. Allele DRB1*04:02 is significantly associated with specific sarcodosis phenotypes such as eye, parotid and salivary gland involvement. An idiopathic, systemic, inflammatory disease characterized by the formation of immune granulomas in involved organs. Granulomas predominantly invade the lungs and the lymphatic system, but also skin, liver, spleen, eyes and other organs may be involved.
Multiple sclerosis (MS):
Disease susceptibility is associated with variants affecting the gene represented in this entry. In populations of European descent, allele DRB1*15:01 has the strongest association with multiple sclerosis among all HLA class II alleles. Additional risk is associated with the strongly linked alleles DRB1*03:01 and DQB1*02:01 as well as with allele DRB1*13:03 (PubMed:21833088). It is postulated that bacterial or viral infection triggers the autoimmune MS. Microbial peptides having low affinity crossreactivity to MBP autoantigen, may stimulate autoreactive T cells via molecular mimicry and initiate the autoimmune inflammation (PubMed:19303388). A multifactorial, inflammatory, demyelinating disease of the central nervous system. Sclerotic lesions are characterized by perivascular infiltration of monocytes and lymphocytes and appear as indurated areas in pathologic specimens (sclerosis in plaques). The pathological mechanism is regarded as an autoimmune attack of the myelin sheath, mediated by both cellular and humoral immunity. Clinical manifestations include visual loss, extra-ocular movement disorders, paresthesias, loss of sensation, weakness, dysarthria, spasticity, ataxia and bladder dysfunction. Genetic and environmental factors influence susceptibility to the disease.
Allele DRB1*15:01 is associated with increased susceptibility to Goodpasture syndrome. Can present a self-peptide derived from COL4A3 (GWISLWKGFSF) on TCR (TRAV19 biased) in pathogenic CD4-positive T-helper 1 and T-helper 17 cells, triggering autoimmune inflammation.
Rheumatoid arthritis (RA):
Disease susceptibility is associated with variants affecting the gene represented in this entry. Alleles DRB1*04:01; DRB1*04:04; DRB1*04:05; DRB1*04:08; DRB1*10:01; DRB1*01:01 and DRB1*01:02 are associated with increased susceptibility to rheumatoid arthritis, where affected individuals have antibodies to cyclic citrullinated peptide (anti-CCP-positive rheumatoid arthritis). Variations at position 40 in the peptide-binding cleft of these alleles explain most of the association to rheumatoid arthritis risk. An inflammatory disease with autoimmune features and a complex genetic component. It primarily affects the joints and is characterized by inflammatory changes in the synovial membranes and articular structures, widespread fibrinoid degeneration of the collagen fibers in mesenchymal tissues, and by atrophy and rarefaction of bony structures.

Extracellular: 30-227
Helical: 228-248
Cytoplasmic: 249-266

Ubiquitinated by MARCHF1 and MARCHF8 at Lys-254 leading to sorting into the endosome system and down-regulation of MHCII.