Restoration of ig secretion: Mutation of germline-encoded residues in T15L chains leads to secretion of free light chains and assembled antibody complexes bearing secretion-impaired heavy chains

Elizabeth A. Whitcomb, Tammy M. Martin, Marvin B. Rittenberg

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

We previously described T15H chain mutants that were impaired in assembly with L chain and in ability to be secreted from the cell. The unmutated T15L chain is unusual in that it is secretion-impaired in the absence of assembly with H chain. The T15L chain preferentially pairs with T15H in vivo, suggesting that if we introduced mutations that would allow secretion of free T15L chain, they might also lead to the secretion of the complex with the defective H chain. We mutated four positions in the germline T15L that had amino acids infrequently found in other κ-chains. Mutation to the most frequently occurring amino acid at three of the four positions allowed secretion of free L chain, while the combination of two secretion-restoring mutations was synergistic. Coexpression of secretion-restored mutant L chains with the secretion-defective mutant H chains rescued secretion of the assembled H2L2 complex, suggesting that during somatic hypermutation in vivo, deleterious mutations at the H chain may be compensated by mutations on the L chain. To our knowledge, this is the first example of mutations in IgL chains that are able to restore secretion-defective H chains to secretion competence in mammalian cells.

Original languageEnglish (US)
Pages (from-to)1903-1909
Number of pages7
JournalJournal of Immunology
Volume170
Issue number4
DOIs
StatePublished - Feb 15 2003

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

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