Follicular Dendritic Cells Modulate Germinal Center B Cell Diversity through Fc?RIIB.

ABSTRACT: Follicular dendritic cells (FDCs), a rare and enigmatic stromal cell type in the B cell follicles of secondary lymphoid organs, store and present antigen to B cells. While essential for germinal center (GC) responses, their exact role during GC B cell selection remains unknown. FDCs upregulate the inhibitory IgG Fc receptor Fc?RIIB during GC formation. We show that the stromal deficiency of Fc?RIIB does not affect GC B cell frequencies compared to wild-type mice. However, in the absence of Fc?RIIB on FDCs, GCs show aberrant B cell selection during autoreactive and selective foreign antigen responses. These GCs are more diverse as measured by the AidCreERT2 -confetti system and show the persistence of IgM+ clones with decreased numbers of IgH mutations. Our results show that FDCs can modulate GC B cell diversity by the upregulation of Fc?RIIB. Permissive clonal selection and subsequent increased GC diversity may affect epitope spreading during autoimmunity and foreign responses.

SUBMITTER: van der Poel CE 

PROVIDER: S-EPMC7015177 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature