Human leukocyte antigen DQ2.5 (HLA-DQ2.5) (HLA-DQ2.5)

Human leukocyte antigen DQ2.5 (HLA-DQ2.5) is a cell-surface receptor and member of the major histocompatibility complex (MHC) class II family, consisting of a heterodimer encoded by the DQA1*05 and DQB1*02 alleles. This heterodimer is essential for antigen presentation to CD4+ T cells, binding to specific peptides—including gluten fragments—and playing a central role in the activation of adaptive immune responses. HLA-DQ2.5 is strongly associated with the pathogenesis of celiac disease (present in ~90% of patients), type 1 diabetes, and several other autoimmune disorders due to its preferential binding and presentation of specific peptide antigens that can trigger pathological immune responses[1][6][7][8][10]. Structurally, HLA-DQ2.5 displays unique peptide-binding characteristics, including high affinity for selective peptides and unusually high association with the invariant chain peptide CLIP, due in part to decreased sensitivity to HLA-DM-mediated peptide exchange[1][3]. No approved drugs directly target HLA-DQ2.5, but its presence serves as a critical biomarker for autoimmune disease risk and diagnosis. Direct modulation of HLA-DQ2.5 is therapeutically challenging given the receptor's essential role in immunity and broad tissue distribution[1][6][7].

Other names

HLA-DQ2.5 heterodimerDQ2.5HLA-DQA1*05:01/DQB1*02:01 (cis DQ2.5)HLA-DQ α^5β^2

Modulation of peptide binding to alter T cell activation (potential mechanism in experimental immune therapies); Inhibition of antigen presentation (potential mechanism under investigation)