<i>Cosmc</i> deficiency causes spontaneous autoimmunity by breaking B cell tolerance.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 34613773.
- Also identified by DOI 10.1126/sciadv.abg9118 and PMC identifier 8494437.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Factors regulating the induction and development of B cell–mediated autoimmunity are not well understood. Here, we report that targeted deletion in murine B cells of X-linked <i>Cosmc</i>, encoding the chaperone required for expression of core 1 O-glycans, causes the spontaneous development of autoimmune pathologies due to a breakdown of B cell tolerance. BC-<i>Cosmc</i>KO mice display multiple phenotypic abnormalities, including severe weight loss, ocular manifestations, lymphadenopathy, and increased female-associated mortality. Disruption of B cell tolerance in BC-<i>Cosmc</i>KO mice is manifested as elevated self-reactive IgM and IgG autoantibodies. <i>Cosmc</i>-deficient B cells exhibit enhanced basal activation and responsiveness to stimuli. There is also an elevated frequency of spontaneous germinal center B cells in BC-<i>Cosmc</i>KO mice. Mechanistically, loss of <i>Cosmc</i> confers enhanced B cell receptor (BCR) signaling through diminished BCR internalization. The results demonstrate that <i>Cosmc</i>, through control of core 1 O-glycans, is a previously unidentified immune checkpoint gene in maintaining B cell tolerance.