page_title: HLA-DQ
section_title: Structure, Functions, Genetics
hierarchical_section_title: HLA-DQ / Structure, Functions, Genetics
caption_attribution_description: English: Molecular basis of the T-cell-mediated immunity.
context_page_description: HLA-DQ is a cell surface receptor protein found on antigen-presenting cells. It is an αβ heterodimer of type MHC class II. The α and β chains are encoded by two loci, HLA-DQA1 and HLA-DQB1, that are adjacent to each other on chromosome band 6p21.3. Both α-chain and β-chain vary greatly. A person often produces two α-chain and two β-chain variants and thus 4 isoforms of DQ. The DQ loci are in close genetic linkage to HLA-DR, and less closely linked to HLA-DP, HLA-A, HLA-B and HLA-C.
  Different isoforms of DQ can bind to and present different antigens to T-cells. In this process T-cells are stimulated to grow and can signal B-cells to produce antibodies. DQ functions in recognizing and presenting foreign antigens. But DQ is also involved in recognizing common self-antigens and presenting those antigens to the immune system in order to develop tolerance from a very young age.
  When tolerance to self proteins is lost, DQ may become involved in autoimmune disease. Two autoimmune diseases in which HLA-DQ is involved are coeliac disease and diabetes mellitus type 1. DQ is one of several antigens involved in rejection of organ transplants.
caption: HLA DQ Receptor with bound peptide and TCR
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