The role of Bruton's tyrosine kinase in the development and BCR/TLR-dependent activation of AM14 rheumatoid factor B cells
Department of Medicine, Division of Rheumatology
Animals; B-Lymphocytes; Female; *Lymphocyte Activation; Male; Mice; Mice, Inbred BALB C; Mice, Inbred CBA; Mice, Transgenic; Protein-Tyrosine Kinases; Receptors, Antigen, B-Cell; Rheumatoid Factor; Toll-Like Receptors
Cell and Developmental Biology | Immunity
The protein kinase Btk has been implicated in the development, differentiation, and activation of B cells through its role in the BCR and TLR signaling cascades. These receptors and in particular, the BCR and either TLR7 or TLR9 also play a critical role in the activation of autoreactive B cells by RNA- or DNA-associated autoantigens. To explore the role of Btk in the development of autoreactive B cells, as well as their responses to nucleic acid-associated autoantigens, we have now compared Btk-sufficient and Btk-deficient mice that express a prototypic RF BCR encoded by H- and L-chain sdTgs. These B cells bind autologous IgG2a with low affinity and only proliferate in response to IgG2a ICs that incorporate DNA or RNA. We found that Btk-sufficient RF(+) B cells mature into naive FO B cells, all of which express the Tg BCR, despite circulating levels of IgG2a. By contrast, a significant proportion of Btk-deficient RF(+) B cells acquires a MZ or MZ precursor phenotype. Remarkably, despite the complete inability of RF(+) Xid/y B cells to respond to F(ab')2 anti-IgM, RF(+) Xid/y B cells could respond well to autoantigen-associated ICs. These data reveal unique features of the signaling cascades responsible for the activation of autoreactive B cells.
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Citation: Nundel K, Busto P, Debatis M, Marshak-Rothstein A. The role of Bruton's tyrosine kinase in the development and BCR/TLR-dependent activation of AM14 rheumatoid factor B cells. J Leukoc Biol. 2013 Nov;94(5):865-75. doi: 10.1189/jlb.0313126. Link to article on publisher's site
Journal of leukocyte biology
Nundel, Kerstin; Busto, Patricia; Debatis, Michelle E.; and Marshak-Rothstein, Ann, "The role of Bruton's tyrosine kinase in the development and BCR/TLR-dependent activation of AM14 rheumatoid factor B cells" (2013). University of Massachusetts Medical School Faculty Publications. 374.