A bispecific antibody targeting HLA-DQ2.5-gluten peptides potently blocks gluten-specific T cells induced by gluten ingestion in patients with celiac disease

The gluten -free diet for celiac disease (CeD) is restrictive and often fails to induce complete symptom and/or mucosal disease remission. Central to CeD pathogenesis is the gluten -specific CD4 + T cell that is restricted by HLA-DQ2.5 in over 85% of CeD patients, making HLA-DQ2.5 an attractive target for suppressing glutendependent immunity. Recently, a novel anti-HLA-DQ2.5 antibody that specifically recognizes the complexes of HLA-DQ2.5 and multiple gluten epitopes was developed (DONQ52). Objective: To assess the ability of DONQ52 to inhibit CeD patient -derived T -cell responses to the most immunogenic gluten peptides that encompass immunodominant T cell epitopes. Methods: We employed an in vivo gluten challenge model in patients with CeD that affords a quantitative readout of disease -relevant gluten -specific T -cell responses. HLA-DQ2.5 + CeD patients consumed food containing wheat, barley, or rye for 3 days with collection of blood before (D1) and 6 days after (D6) commencing the challenge. Peripheral blood mononuclear cells were isolated and assessed in an interferon (IFN)- gamma enzyme -linked immunosorbent spot assay (ELISpot) testing responses to gluten peptides encompassing a series of immunodominant T cell epitopes. The inhibitory effect of DONQ52 (4 or 40 mu g/mL) was assessed and compared to pan-HLA-DQ blockade (SPVL3 antibody). Results: In HLA-DQ2.5 + CeD patients, DONQ52 reduced T cell responses to all wheat gluten peptides to an equivalent or more effective degree than pan-HLA-DQ antibody blockade. It reduced T cell responses to a cocktail of the most immunodominant wheat epitopes by a median of 87% (IQR 72 -92). Notably, DONQ52 also substantially reduced T -cell responses to dominant barley hordein and rye secalin derived peptides. DONQ52 had no effect on T -cell responses to non -gluten antigens. Conclusion: DONQ52 can significantly block HLA-DQ2.5-restricted T cell responses to the most highly immunogenic gluten peptides in CeD. Our findings support in vitro data that DONQ52 displays selectivity and broad cross -reactivity against multiple gluten peptide:HLA-DQ2.5 complexes. This work provides proof -of -concept multi -specific antibody blockade has the potential to meaningfully inhibit pathogenic gluten -specific T -cell responses in CeD and supports ongoing therapeutic development.