Reduced isotype switching in splenic B cells from mice deficient in mismatch repair enzymes

Carol E. Schrader, Winfried Edelmann, Raju Kucherlapati, Janet Stavnezer

Research output: Contribution to journalArticlepeer-review

192 Scopus citations


Mice deficient in various mismatch repair (MMR) enzymes were examined to determine whether this repair pathway is involved in antibody class switch recombination. Splenic B cells from mice deficient in Msh2, Mlh1, Pms2, or Mlh1 and Pms2 were stimulated in culture with lipopolysaccharide (LPS) to induce immunoglobulin (Ig)G2b and IgG3, LPS and interleukin (IL)-4 to induce IgG1, or LPS, anti-δ-dextran, IL-4, IL-5, and transforming growth factor (TGF)-β1 to induce IgA. After 4 d in culture, cells were surface stained for IgM and non-IgM isotypes and analyzed by FACS®. B cells from MMR-deficient mice show a 35-75% reduction in isotype switching, depending on the isotype and on the particular MMR enzyme missing. IgG2b is the most affected, reduced by 75% in Mlh1-deficient animals. The switching defect is not due to a lack of maturation of the B cells, as purified IgM+IgD+ B cells show the same reduction. MMR deficiency had no effect on cell proliferation, viability, or apoptosis, as detected by [3H]thymidine incorporation and by propidium iodide staining. The reduction in isotype switching was demonstrated to be at the level of DNA recombination by digestion-circularization polymerase chain reaction (DC-PCR). A model of the potential role for MMR enzymes in class switch recombination is presented.

Original languageEnglish (US)
Pages (from-to)323-330
Number of pages8
JournalJournal of Experimental Medicine
Issue number3
StatePublished - Aug 2 1999


  • Class switch recombination
  • Mlh1
  • Msh2
  • Pms2

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


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