Berkowska MA, Schickel JN, Grosserichter-Wagener C, de Ridder D, Ng YS, van Dongen JJM, Meffre E, van Zelm MC. Circulating Human CD27-IgA+ Memory B Cells Recognize Bacteria with Polyreactive Igs.
THE JOURNAL OF IMMUNOLOGY 2015;
195:1417-26. [PMID:
26150533 DOI:
10.4049/jimmunol.1402708]
[Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 06/08/2015] [Indexed: 01/01/2023]
Abstract
The vast majority of IgA production occurs in mucosal tissue following T cell-dependent and T cell-independent Ag responses. To study the nature of each of these responses, we analyzed the gene-expression and Ig-reactivity profiles of T cell-dependent CD27(+)IgA(+) and T cell-independent CD27(-)IgA(+) circulating memory B cells. Gene-expression profiles of IgA(+) subsets were highly similar to each other and to IgG(+) memory B cell subsets, with typical upregulation of activation markers and downregulation of inhibitory receptors. However, we identified the mucosa-associated CCR9 and RUNX2 genes to be specifically upregulated in CD27(-)IgA(+) B cells. We also found that CD27(-)IgA(+) B cells expressed Abs with distinct Ig repertoire and reactivity compared with those from CD27(+)IgA(+) B cells. Indeed, Abs from CD27(-)IgA(+) B cells were weakly mutated, often used Igλ chain, and were enriched in polyreactive clones recognizing various bacterial species. Hence, T cell-independent IgA responses are likely involved in the maintenance of gut homeostasis through the production of polyreactive mutated IgA Abs with cross-reactive anti-commensal reactivity.
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