Clonal Expansions of B Lymphocytes in Old Mice

Joël LeMaoult, Sylvie Delassus, Ruben Dyall, Janko Nikolić-Žugić, Philippe Kourilsky, Marc E. Weksler

Research output: Contribution to journalArticle

46 Scopus citations

Abstract

The effect of age on the diversity of the murine Ig heavy chain repertoire has been studied in unimmunized C57BL/6 mice. We examined the heterogeneity of complementarity-determining region 3 (CDR3) sizes of Ig mRNA of the IgM and IgG isotypes using two VH families, VHJ558 and VHQ52, which together account for approximately 65% of the Ab repertoire. The broad and bell-shaped profiles representing the diversity of the VHJ558 family in the spleen of 2- to 6-mo-old C57BL/6 mice becomes significantly less diverse after 12 mo of age and by 18 mo of age, single CDR3 sizes that dominate the profiles can be observed in the spleens of >85% of the mice. Readable sequences have been obtained from 40 dominant mRNA CDR3 size species indicating that they represent clonal populations of B lineage. There are no significant homologies among these sequences. Clones of B lymphocytes that express a dominant CDR3 mRNA species can also be found in the bone marrow, the mesenteric lymph nodes, and the thymus of C57BL/6 mice >18 mo of age. Some clones of B cells can be detected in only one lymphoid compartment; others are found in two or more compartments. The splenic B cell clones in C57BL/6 mice >18 mo of age are stable for at least 2 mo. The CDR3 mRNA species that dominate the splenic repertoire of Ig mRNA-expressing cells in vivo do not dominate the repertoire of splenic B cells activated in vitro by bacterial LPS, suggesting that they represent a modest population of B cells expressing high levels of Ig mRNA.

Original languageEnglish (US)
Pages (from-to)3866-3874
Number of pages9
JournalJournal of Immunology
Volume159
Issue number8
StatePublished - Oct 15 1997

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

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