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J Immunol. 2009 Jan 1;182(1):138-47.

Deviation of the B cell pathway in senescent mice is associated with reduced surrogate light chain expression and altered immature B cell generation, phenotype, and light chain expression.

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  • 1Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, FL 33101, USA.

Abstract

B lymphopoiesis in aged mice is characterized by reduced B cell precursors and an altered Ab repertoire. This likely results, in part, from reduced surrogate L chains in senescent B cell precursors and compromised pre-BCR checkpoints. Herein, we show that aged mice maintain an ordinarily minor pool of early c-kit(+) pre-B cells, indicative of poor pre-BCR expression, even as pre-BCR competent early pre-B cells are significantly reduced. Therefore, in aged mice, B2 B lymphopoiesis shifts from dependency on pre-BCR expansion and selection to more pre-BCR-deficient pathways. B2 c-kit(+) B cell precursors, from either young or aged mice, generate new B cells in vitro that are biased to larger size, higher levels of CD43, and decreased kappa L chain expression. Notably, immature B cells in aged bone marrow exhibit a similar phenotype in vivo. We hypothesize that reduced surrogate L chain expression contributes to decreased pre-B cells in aged mice. The B2 pathway is partially blocked with limited B cell development and reduced pre-BCR expression and signaling. In old age, B2 pathways have limited surrogate L chain and increasingly generate new B cells with altered phenotype and L chain expression.

PMID:
19109144
[PubMed - indexed for MEDLINE]
PMCID:
PMC2749601
Free PMC Article
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