SLE is a systemic autoimmune disease characterized by profound B cell abnormalities and multiple autoantibody production. However, despite major advances in the field of human B cell biology, the precise antigenic and cellular mechanisms that underlie the activation, diversification and expansion of B cells in SLE remain poorly understood. Moreover, a precise understanding of the relative participation of different B cell subsets during acute disease exacerbations has been hampered by disease heterogeneity, imprecise B cell phenotyping and the lack of high-throughput technologies needed to define the antigenic forces driving the generation and selection of autoreactive B cells and serum autoantibodies. During the current ACE cycle we have established the tools required to address these questions including multi-dimensional flow cytometry; next generation sequencing (NGS); large scale single cell antibody generation; and bioinformatics platforms for the integrative analysis of high-density immunological, transcriptional and clinical data. Moreover, we have initiated collaborations with expert groups for the study of B cell and ASC epigenetics (Dr. Boss, Collaborative Agenda PI) and for the analysis of serum antibody proteomics (Dr. Cheung; CST). In this Principal Project of the Emory ACE U19, we proposed to build on these accomplishments to dissect the participation of B cell and ASC subsets through the following specific aims: Aim 1. Participation and antigenic selection of different B cell compartments in SLE flares using repertoire analysis by NGS and single cell antibody production; Aim 2. Relative contribution of short-lived and long-lived antibody secreting cells to the SLE serum autoantibody proteome; and Aim 3. Epigenetic and transcriptional control of SLE B cells in conjunction with the Collaborative Project. The work proposed is highly synergistic with the Collaborative Agenda and the Pilot Project and has a high degree of innovation in terms of the questions asked and the experimental approach. The expect results should be of far-reaching significance for our understanding of the pathogenic mechanisms acting upon B cells in human autoimmunity and for the rationale design of safer and more effective therapies.

This project will provide critical insight into the contribution of different B cells and antibody secreting cells to the autoantibody repertoire and disease process in human SLE. Together with the Collaborative Project, it will also study the epigenome and transcriptional program of autoimmune B cells