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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.


Paola Massari

Andrew T. Vaughan

Louise S. Brackenbury

Andrew Gorringe

Robert S. Heyderman

Neil A. Williams


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.


Massari, P., Vaughan, A. T., Brackenbury, L. S., Davenport, V., Gorringe, A., Heyderman, R. S., & Williams, N. A. (2010). Neisseria lactamica selectively induces mitogenic proliferation of the naive B cell pool via cell surface Ig. Journal of Immunology, 185(6), 3652-3660.

Journal Article Type Article
Publication Date Sep 15, 2010
Journal Journal of Immunology
Print ISSN 0022-1767
Electronic ISSN 1550-6606
Publisher American Association of Immunologists
Peer Reviewed Peer Reviewed
Volume 185
Issue 6
Pages 3652-3660
Keywords Neisseria lactamica IgM B cell mitogen
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