Antibodies Encoded by FCRL4-Bearing Memory B Cells Preferentially Recognize Commensal Microbial Antigens

• Published in: The Journal of immunology (1950) Vol. 200; no. 12; pp. 3962 - 3969
• Main Authors: Liu, Yanling, McDaniel, Jonathan R, Khan, Srijit, Campisi, Paolo, Propst, Evan J, Holler, Theresa, Grunebaum, Eyal, Georgiou, George, Ippolito, Gregory C, Ehrhardt, Götz R A
• Format: Journal Article
• Language: English
• Published: United States American Association of Immunologists 15-06-2018
• Subjects: Antibodies - immunology; Antigens; Antigens - immunology; B-Lymphocytes - immunology; Cell Line; Comparative analysis; Gene Expression - immunology; HEK293 Cells; Humans; Immunoglobulin A; Immunoglobulin A - immunology; Immunologic Memory - immunology; Immunological memory; Immunoregulation; Lymphocyte Activation - immunology; Lymphocytes B; Memory cells; Microbiota; Microbiota - immunology; Molecular chains; Mutation; Phenotype; Phenotypes; Receptors, Fc - immunology
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.1701549

FCRL4, a low-affinity IgA Ab receptor with strong immunoregulatory potential, is an identifying feature of a tissue-based population of memory B cells (Bmem). We used two independent approaches to perform a comparative analysis of the Ag receptor repertoires of FCRL4
and FCRL4
Bmem in human tonsils. We determined that FCRL4
Bmem displayed lower levels of somatic mutations in their Ag receptors compared with FCRL4
Bmem but had similar frequencies of variable gene family usage. Importantly, Abs with reactivity to commensal microbiota were enriched in FCRL4
cells, a phenotype not due to polyreactive binding characteristics. Our study links expression of the immunoregulatory FCRL4 molecule with increased recognition of commensal microbial Ags.