Our goal is to understand the role of autoreactive B cells in tissues draining the pancreas and their role in the type 1 diabetes (T1D) autoimmune response. While B cells are responsible for secreting autoantibodies, B cells have other functions including secretion of effector cytokines, antigen presentation and costimulation of T cell responses. Using a multiplexed, single cell interrogation assay called microengraving, we saw, ex vivo, that there is a statistically more frequent number of immature (IgM secreting) CD20 B cells secreting antibodies reactive with islet antigen GAD65 in the spleen from 50% individuals examined with recent onset (0-7 years) T1D as compared to those from healthy control: these cells could also be seen on the spleen of some GADA+ individuals without disease and in some individuals with long-term T1D. We saw this reservoir of GADA-secreting B cells of a mature phenotype (secreting IgG1, IgG3 or IgA) in the spleen of two individuals with recent onset T1D. We saw a low frequency of immature CD20 B cells secreting antibodies reactive with proinsulin in all groups. We wished to interrogate the autoreactive B cells for their cytokine secretion, but due to cell demise in the single cell assay at time points greater than 24 hours, we developed a 7-day culture assay that allows for survival of B cells and identification of these cells by their autoantibody secretion and cytokine profile in a two-color ELISpot assay. We are interrogating spleen samples from control individuals, individuals with autoantibody, but without disease, individuals with recent onset T1D (0-7 years), and individuals with long-term T1D (>7 years) for co-secretion of GAD65 autoantibody and IL-6/IL-10 or LTa/TNFa. These studies will provide a profile of the function of autoreactive B cells from individuals with T1D and their role in the autoreactive disease process.