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PLoS One. 2015 Jun 12;10(6):e0129879. doi: 10.1371/journal.pone.0129879. eCollection 2015.

Innate Response Activator (IRA) B Cells Reside in Human Tonsils and Internalize Bacteria In Vitro.

Author information

1
Novartis Vaccines and Diagnostics (a GSK company), Research Center, Via Fiorentina 1, Siena, Italy.
2
Otorhinolaryngology Department, University Hospital Le Scotte, Strada delle Scotte 14, Siena, Italy.
3
Department of Medical Biotechnologies, Infectious Unit, University Hospital Le Scotte, Strada delle Scotte 14, Siena, Italy.

Abstract

Innate response activator (IRA) B cells have been described in mice as a subset of B-1a B cells that produce granulocyte/macrophage colony-stimulating factor (GM-CSF) and have been found in the spleen upon activation. In humans, identification, tissue localization and functionality of these lymphocytes are poorly understood. We hypothesized that IRA B cells could reside in human palatine tonsils, which are a first line of defense from infection of the upper respiratory tract. In the present work, we used flow cytometry and confocal microscopy to identify and characterize human IRA (hIRA) B cells in tonsils. We show that CD19⁺CD20⁺GM-CSF⁺ B cells are present in the tonsils of all the subjects studied at a frequency ranging between ~0.2% and ~0.4% of the conventional CD19⁺CD20⁺GM-CSF⁻ B cells. These cells reside within the B cell follicles, are mostly IgM⁺IgD⁺, express CD5 and show phagocytic activity. Our results support a role for hIRA B cells in the effector immune response to infections in tonsils.

PMID:
26066485
PMCID:
PMC4466315
DOI:
10.1371/journal.pone.0129879
[Indexed for MEDLINE]
Free PMC Article

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