James, L. K. | bioRxiv Science

bioRxiv2021

Integrated single-cell transcriptomics and epigenomics reveals strong germinal center-associated etiology of autoimmune risk loci

The germinal center (GC) response is critical for both effective adaptive immunity and establishing peripheral tolerance by limiting auto-reactive B cells. Dysfunction in these processes can lead to defects in immune response to pathogens or contribute to autoimmune disease. To understand the gene regulatory principles underlying the GC response, we generated a single-cell transcriptomic and epigenomic atlas of the human tonsil, a widely studied and representative lymphoid tissue. We characterize diverse immune cell subsets and build a trajectory of dynamic gene expression and transcription factor activity during B cell activation, GC formation, and plasma cell differentiation. We subsequently leverage cell type-specific transcriptomic and epigenomic maps to interpret potential regulatory impact of genetic variants implicated in autoimmunity, revealing that many exhibit their greatest regulatory potential in GC cell populations. Together, these analyses provide a powerful new cell type-resolved resource for the interpretation of cellular and genetic causes underpinning autoimmune disease. One sentence summarySingle-cell chromatin accessibility landscapes of immune cell subsets reveal regulatory potential of autoimmune-associated genetic variants during the germinal center response.

genomics↗

bioRxiv2020

Antibody repertoire and gene expression dynamics of diverse human B cell states during affinity maturation.

In response to antigen challenge, B cells clonally expand, undergo selection and differentiate to produce mature B cell subsets and high affinity antibodies. However, the interplay between dynamic B cell states and their antibody-based selection is challenging to decipher in primary human tissue. We have applied an integrated analysis of bulk and single-cell antibody repertoires paired with single-cell transcriptomics of human B cells undergoing affinity maturation. We define unique gene expression and antibody repertoires of known and novel B cell states, including a pre-germinal centre state primed to undergo class switch recombination. We dissect antibody class-dependent gene expression of germinal centre and memory B cells to find that class switching prior to germinal centre entry dictates the capacity of B cells to undergo antibody-based selection and differentiate. Together, our analyses provide unprecedented resolution into the gene expression and selection dynamics that shape B cell-mediated immunity.

immunology↗