Neisseria lactamica selectively induces mitogenic proliferation of the naive B cell pool via cell surface Ig

Massari, Paola; Vaughan, Andrew T.; Brackenbury, Louise S.; Davenport, Victoria; Gorringe, Andrew; Heyderman, Robert S.; Williams, Neil A.

Abstract

Neisseria lactamica is a commensal bacteria that colonizes the human upper respiratory tract mucosa during early childhood. In contrast to the closely related opportunistic pathogen Neisseria meningitidis, there is an absence of adaptive cell-mediated immunity to N. lactamica during the peak age of carriage. Instead, outer membrane vesicles derived from N. lactamica mediate a B cell-dependent proliferative response in mucosal mononuclear cells that is associated with the production of polyclonal IgM. We demonstrate in this study that this is a mitogenic human B cell response that occurs independently of T cell help and any other accessory cell population. The ability to drive B cell proliferation is a highly conserved property and is present in N. lactamica strains derived from diverse clonal complexes. CFSE staining of purified human tonsillar B cells demonstrated that naive IgD+ and CD27- B cells are selectively induced to proliferate by outer membrane vesicles, including the innate CD5+ subset. Neither purified lipooligosaccharide nor PorB from N. lactamica is likely to be responsible for this activity. Prior treatment of B cells with pronase to remove cell-surface Ig or treatment with BCR-specific Abs abrogated the proliferative response to N. lactamica outer membrane vesicles, suggesting that this mitogenic response is dependent upon the BCR. Copyright © 2010 by The American Association of Immunologists, Inc.

• Journal Article Type: Article
• Publication Date: Sep 15, 2010
• Deposit Date: Jun 9, 2011
• Journal: Journal of Immunology
• Print ISSN: 0022-1767
• Publisher: American Association of Immunologists
• Peer Reviewed: Peer Reviewed
• Volume: 185
• Issue: 6
• Pages: 3652-3660
• DOI: https://doi.org/10.4049/jimmunol.0902468
• Keywords: Neisseria lactamica IgM B cell mitogen
• Public URL: https://uwe-repository.worktribe.com/output/976694
• Publisher URL: http://dx.doi.org/10.4049/jimmunol.0902468
• Contract Date: Nov 15, 2016