Loss of tolerance of anti-dsDNA B cells in mice overexpressing CD19.

Published

Journal Article

Mice transgenic for the R4A-Cmu heavy chain of an anti-dsDNA antibody, maintain tolerance by anergy and deletion. In C57BL/6 mice overexpressing CD19, a molecule, which lowers the threshold for B cell activation, elevated levels of serum autoantibodies have been observed. In the present study, we wished to determine whether CD19 overexpression could alter the induction of tolerance in R4A-Cmu mice and lead to the secretion of transgenic anti-dsDNA antibodies. We, therefore, bred R4A-Cmu transgenic mice-to-mice transgenic for human CD19 (hCD19) and generated R4A-Cmu mice heterozygous and homozygous for hCD19. We, now report the spontaneous secretion of transgenic IgM anti-dsDNA antibody in the sera of R4A-Cmu mice overexpressing CD19, indicative of a loss of B cell tolerance. We observe that transgenic B cells secreting anti-dsDNA antibody in these mice are T independent and display a marginal zone like phenotype althought they do not reside in the MZ. In addition, they appear to be derived from the conventional B2 subset rather than the B1 subset. Interestingly, a subset of the anti-dsDNA B cells in these mice still display the phenotype and functional characteristics of anergic B cells. These B cells cannot be activated to secrete antibody following BCR crosslinking, however, they are hyper-responsive to activation by innate signaling mechanisms. This suggests that CD19 overexpression may promote anergic B cells to escape tolerance by converging with BCR independent pathways, thereby rendering these B cells hyper-responsive to innate signaling.

Full Text

Duke Authors

Cited Authors

  • Taylor, DK; Ito, E; Thorn, M; Sundar, K; Tedder, T; Spatz, LA

Published Date

  • April 2006

Published In

Volume / Issue

  • 43 / 11

Start / End Page

  • 1776 - 1790

PubMed ID

  • 16430962

Pubmed Central ID

  • 16430962

International Standard Serial Number (ISSN)

  • 0161-5890

Digital Object Identifier (DOI)

  • 10.1016/j.molimm.2005.11.003

Language

  • eng

Conference Location

  • England