FITC Mouse Anti-Human HLA-DR, DP, DQ Antibody (Tu39)

HLA-DR、DP、DQ are the three classical class II human leukocyte antigen (HLA) isotypes, encoded within the HLA-D region of the major histocompatibility complex. All three are heterodimeric glycoproteins composed of an α chain and a β chain that present peptide antigens to CD4⁺ T cells, but they differ in their gene organization, polymorphism, expression, and intracellular assembly requirements. HLA-DR is the most extensively studied and most polymorphic isotype; its DRA gene is essentially non-polymorphic while the DRB1 locus harbors the greatest allelic diversity in the class II region, and its efficient peptide loading is well recognized to depend on both invariant chain (Ii) and HLA-DM. HLA-DQ is formed by polymorphic DQA1 and DQB1 chains and is strongly linked to celiac disease and other autoimmune conditions; unlike DR, DQ molecules can form SDS-stable dimers supported by Ii even in the absence of HLA-DM. HLA-DP has a more restricted peptide repertoire and less well-defined roles in autoimmunity, though certain DP alleles are risk factors for myasthenia gravis and berylliosis; uniquely, HLA-DP can also form stable dimers with HLA-DM alone and exhibits distinct chaperone requirements compared to DR and DQ.