Open Access

ARTICLE

Role of IL-10 in the distribution of B cell subsets in the mouse B-1 cell population

Jacques-Olivier Pers¹, Christophe Jamin¹, Pierre Youinou¹, Jeannine Charreire²

1 Laboratory of Immunology, Brest University Medical School Hospital, BP 824, F 29609 Brest, France
2 INSERM Unit 477, Cochin Hospital, René Descartes University, Paris, France

* Corresponding Author: PierreYouinou,

European Cytokine Network 2003, 14(3), 178-185.

Abstract

The B lymphocyte compartment is comprised of B-1 and B-2 cells. The former is divided into B-1a, which express CD5, and B-1b cells which do not: both are self-renewing, although the mechanisms are yet to be identified. IL-10^–/– mice were used to delineate the role of the B cell activator IL-10 in this process. Its absence had no effect on the total number of B-1 cells, but decreased that of B-1a cells (0.8 ± 0.1 versus 1.7 ± 0.2 × 10⁶ , p < 0.002), while increasing that of B-1b cells (1.9 ± 0.4 versus 0.8 ± 0.1 × 10⁶ , p < 0.03). The number of B-1a cells remained low in IL-10-injected IL-10^–/– mice, whereas the excess of B-1b cells further increased (2.8 ± 0.2 versus 1.6 ± 0.4 × 10⁶ , p < 0.03). On the basis that Bax and Bad were augmented in B-1a cells, and Bcl-2 and Bcl-xL reduced, we conclude that the disappearance of B-1a cells, but not B-1b, in IL-10^–/– mice results from their enhanced susceptibility to apoptosis. In addition, culture of IL-10^–/– B-1a and B-1b cells in the presence of IL-10 drives more of the latter than of the former into cycle (p < 0.02). Therefore, IL-10 exerts two, complementary effects on the distribution of B-1 cell sub-populations, rescuing B-1a cells from apoptosis and encouraging B-1b cell proliferation.

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