Antibody repertoire diversification through VH gene replacement in mice cloned from an IgA plasma cell
- Rashmi Kumara,
- Martina P. Bachb,c,
- Federica Mainoldia,
- Mikako Maruyad,
- Satoshi Kishigamie,1,
- Hassan Jumaab,c,
- Teruhiko Wakayamae,1,
- Osami Kanagawaf,
- Sidonia Fagarasand, and
- Stefano Casolaa,2
- aThe Institute of Molecular Oncology (IFOM) of the Italian Foundation for Cancer Research (FIRC), Milan 20139, Italy;
- bInstitute of Immunology, University Clinic Ulm, 89081 Ulm, Germany;
- cDepartment of Molecular Immunology, Albert-Ludwigs University of Freiburg and Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany;
- dCenter for Integrative Medical Sciences, RIKEN Yokohama Institute, Yokohama, Kanagawa 230-0045, Japan;
- eRIKEN Center for Developmental Biology, Kobe, Hyogo 650-0047, Japan; and
- fAkashi City Hospital, Akashi 673-8501, Japan
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Edited by Frederick W. Alt, Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Harvard Medical School, and Howard Hughes Medical Institute, Boston, MA, and approved December 19, 2014 (received for review September 18, 2014)
Significance
Antibodies produced by B cells provide a protective barrier to our organism against the penetration and dissemination of microorganisms. Each antibody recognizes a specific antigen through variable (V) region domains of pairs of immunoglobulin (Ig) heavy (H) and light (L) chains. In mammals, VDJ recombination generates a highly diversified preimmune pool of VH and VL domains. Acquisition of a functional VH rearrangement is thought to prevent further VDJ recombination at the IgH locus. Instead, mice cloned from a terminally differentiated B cell unravel the ability of VDJ recombination to revise a functionally rearranged VH gene through VH replacement. We show that up to 20% of the antibody V gene repertoire of mature B-lymphocytes can be generated through VH replacement.
Abstract
In mammals, VDJ recombination is responsible for the establishment of a highly diversified preimmune antibody repertoire. Acquisition of a functional Ig heavy (H) chain variable (V) gene rearrangement is thought to prevent further recombination at the IgH locus. Here, we describe VHQ52NT; Vκgr32NT Ig monoclonal mice reprogrammed from the nucleus of an intestinal IgA+ plasma cell. In VHQ52NT mice, IgA replaced IgM to drive early B-cell development and peripheral B-cell maturation. In VHQ52NT animals, over 20% of mature B cells disrupted the single productive, nonautoimmune IgH rearrangement through VH replacement and exchanged it with a highly diversified pool of IgH specificities. VH replacement occurred in early pro-B cells, was independent of pre–B-cell receptor signaling, and involved predominantly one adjacent VH germ-line gene. VH replacement was also identified in 5% of peripheral B cells of mice inheriting a different productive VH rearrangement expressed in the form of an IgM H chain. In summary, editing of a productive IgH rearrangement through VH replacement can account for up to 20% of the IgH repertoire expressed by mature B cells.
Footnotes
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↵1Present address: Faculty of Life and Environmental Science, University of Yamanashi, Kofu, Yamanashi 400-8510, Japan.
- ↵2To whom correspondence should be addressed. Email: stefano.casola{at}ifom.eu.
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Author contributions: S.C. designed research; R.K., M.P.B., and F.M. performed research; M.M., S.K., T.W., O.K., and S.F. contributed new reagents/analytic tools; R.K., M.P.B., F.M., H.J., and S.C. analyzed data; and R.K. and S.C. wrote the paper.
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The authors declare no conflict of interest.
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This article is a PNAS Direct Submission.
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This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1417988112/-/DCSupplemental.
