Tu117 - BASTA, a Simple Whole Blood Assay for Measuring Beta-cell Antigen Specific CD4+ T-cell Responses in Type 1 Diabetes

Abstract Text: Type 1 diabetes (T1D) is an autoimmune disease caused by the T cells mediated destruction of the insulin-producing beta-cells. Despite their clear pathogenic role the activity of beta cell antigen specific CD4+ T cells cannot currently be routinely measured in a clinical setting. Here we describe the beta-cell antigen specific T-cell assay – BASTA. BASTA is a simple whole blood assay that can detect human CD4+ T-cell responses to beta-cell antigens by measuring antigen-stimulated IL-2 production. BASTA is both more sensitive and specific than the CFSE-based Proliferation Assay. We used BASTA to identify the regions of preproinsulin which stimulated T-cell responses specifically in blood from people with T1D. BASTA can be done with as little as 2-3 mL of blood. We found that effector memory CD4+ T cells are the primary producers of IL-2 in response to preproinsulin peptides. We then evaluated responses to individual and pooled preproinsulin peptides in a cross-sectional study of paediatric subjects: without T1D, without T1D but with a first-degree relative with T1D, or diagnosed with T1D. In contrast to other preproinsulin peptides, full-length C-peptide (PI33-63) showed excellent specificity for T1D (AUC = 0.86). Further work has defined peptides from other beta cell proteins that elicit T1D specific CD4+ T-cell responses. Because of its simplicity, sensitivity and disease specificity we suggest that BASTA will be a useful tool for monitoring changes in beta-cell specific CD4+ T-cell responses both in research and clinical settings.