Alterations in B cell development, CDR-H3 repertoire and dsDNA-binding antibody production among C57BL/6 ΔD−iD mice congenic for the lupus susceptibility loci sle1, sle2 or sle3

Abstract

Systemic lupus erythematosus (SLE) is an autoimmune disease that reflects a failure to block the production of self-reactive antibodies, especially those that bind double-stranded DNA (dsDNA). Backcrossing the lupus-prone NZM2410 genome onto C57BL/6 led to the identification of three genomic intervals, termed sle1, sle2 and sle3, which are associated with lupus susceptibility. We previously generated a C57BL/6 strain congenic for an immunoglobulin D_H locus (ΔD–iD) that enriches for arginine at dsDNA-binding positions. We individually introduced the ΔD–iD allele into the three sle strains to test whether one or more of these susceptibility loci could affect the developmental fate of B cells bearing arginine-enriched CDR-H3s, the CDR-H3 repertoire created by the D_H and the prevalence of dsDNA-binding antibodies. We found that the combination of the ΔD–iD allele and the sle1 locus led to a decrease in mature, recirculating B cell numbers and an increase in marginal zone cell numbers while maintaining a highly charged CDR-H3 repertoire. ΔD–iD and sle2 had no effect on peripheral B cell numbers, but the CDR-H3 repertoire was partially normalized. ΔD–iD and sle3 led to an increase in marginal zone B cell numbers, with some normalization of hydrophobicity. Mice with ΔD–iD combined with either sle1 or sle3 had increased production of dsDNA-binding IgM and IgG by 12 months of age. These findings indicate that the peripheral CDR-H3 repertoire can be categorically manipulated by the effects of nonimmunoglobulin genes.

• Systemic lupus erythematosus
• Sle
• B-cell repertoire
• third complementary determining region heavy chain
• CDR-H3 and diversity gene segments
• D_H

Acknowledgements

We thank Yingxin Zhuang and Pratibha Kapoor for outstanding technical assistance. We thank Chandra Mohan for providing us with the sle1, sle2 and sle3 mice. This work was supported, in part, by NIH AI48115, AI117703, and DE022736. Flow cytometry was supported by NIH AR48311 and AI027767.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.

Supplementary materials available online