Immature B cells from human and mouse bone marrow can change their surface light chain expression

Paolo Ghia, Alois Gratwohl, Erich Signer, Thomas H. Winkler, Fritz Melchers, Antonius G. Rolink

Research output: Contribution to journalArticlepeer-review


The capacity of bone marrow-derived surface immunoglobulin-positive (sIg+) human and mouse immature B cells, generated either in vitro or in vivo, to change their light (L) chain expression, has been assayed by the number of cells which change in vitro from one type of L chain to the other type, or to no sIg at all. Immature sIg+ B cells were generated in vitro from sIg- precursor cells from human or mouse bone marrow. The immature sIg+ cells expressed RAG-1. Human sIg+ cells expressed κ and λ L chains in ratios between 1:1 and 3:1, whereas in mouse cells, this ratio ranged from 10:1 to 20:1. Upon reculture of the human and mouse κ+ sIg+ cells, about half of them remained κ+, a quarter became λ+, and another quarter became sIg-. Between 1 and 3% expressed both κ and λ chains. Of the human λ+ cells, about two-thirds remained λ+, only 1 to 2% became κ+, while the other third became sIg-. Again, between 1 and 3% expressed both κ and λ L chains. These results indicate that expression of sIgM in the B cell membrane does not terminate L chain gene rearrangement, and that some order exists in κ versus λ gene rearrangements. Hence, human and mouse κ+ immature B cells can become λ+, but very few of the λ+ cells can become κ+, and both can become sIg-. Further, human CD10+/sIg+ κ+ and λ+ cells and mouse B220(low)/sIg(low) κ+ cells enriched from bone marrow, i.e. immature B cells differentiated in vivo, changed their Ig phenotype upon in vitro culture, but in lower frequencies. By contrast, human and mouse mature B cells did not change their L chain or Ig phenotype. Hence, at least a part of the sIg+ immature B cells in bone marrow retain the capacity to change their L chain and Ig phenotype, and this capacity is lost when they become mature, peripheral B cells.

Original languageEnglish
Pages (from-to)3108-3114
Number of pages7
JournalEuropean Journal of Immunology
Issue number11
Publication statusPublished - Nov 1995


  • Human and mouse bone marrow
  • Immature B cells
  • Light chain isotype change

ASJC Scopus subject areas

  • Immunology

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