The control of membrane and secreted heavy chain biosynthesis varies in different immunoglobulin isotypes produced by a monoclonal B cell lymphoma

Roberto Sitia, Cristina Alberini, Roberto Biassoni, Anna Rubartelli, Sandro DeAmbrosis, Daniela Vismara

Research output: Contribution to journalArticle


The control of production of the membrane (m) vs secreted (s) forms of immunoglobulin heavy chains was investigated in a panel of cell lines expressing different heavy chain classes but identical light chains (λ) and variable regions. These cell lines could be induced towards Ig secretion by mitogen treatment. During this process a shift from m to s heavy chain production takes place. Here we show that, similarly to IgA- and IgE-producing B cells, in IgG2a-producing I.29 cells the γms shift was accompanied by a shift in the corresponding mRNAs, with a decrease of γm mRNA and an increase of the γs mRNA in LPS-stimulated cells. By contrast, the μm mRNA was increased in LPS-stimulated IgM-producing cells, albeit these cells synthesized reduced amounts of μm polypeptides. The utilization of the translational level in the early steps of B lymphocyte maturation thus distinguishes the mode of regulation of μ chains from those of the other isotypes. In addition, in B cells a post-translational event blocks the secretion of IgM but not of IgG or IgE.

Original languageEnglish (US)
Pages (from-to)189-197
Number of pages9
JournalMolecular Immunology
Issue number2
StatePublished - Feb 1988


ASJC Scopus subject areas

  • Immunology
  • Molecular Biology

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