Btk dosage determines sensitivity to B cell antigen receptor cross-linking

Anne B. Satterthwaite, Hilde Cheroutre, Wasif N. Khan, Pascalis Sideras, Owen N. Witte

Research output: Contribution to journalArticle

89 Scopus citations

Abstract

Mutations in Btk result in the B cell immunodeficiencies X-linked agammaglobulinemia (XLA) in humans and X-linked immunodeficiency (xid) in mice. Btk is a critical component of signaling pathways regulating B cell development and function. We used a genetic approach to determine whether Btk is also limiting for these processes. One allele of a murine Btk transgene expressed a dosage of Btk (25% of endogenous levels in splenic B cells) sufficient to restore normal numbers of phenotypically mature conventional B cells in xid mice. 2,4,6-trinitrophenyl-Ficoll response, anti-IgM-induced proliferation, B1 cell development, and serum IgM and IgG3 levels remained significantly impaired in these animals. B cells from Btk -/- transgenic mice also responded poorly to anti-IgM, indicating that the xid mutation does not create a dominant negative form of Btk. Response to 2,4,6-trinitrophenyl- Ficoll and B cell receptor cross-linking were increased 3- to 4-fold in xid mice homozygous for the transgene. These results demonstrate that Btk is a limiting component of B cell antigen receptor signaling pathways and suggest that B cell development and response to antigen may require different levels of Btk activity.

Original languageEnglish (US)
Pages (from-to)13152-13157
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume94
Issue number24
DOIs
StatePublished - Nov 25 1997

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