Production of monoclonal antibodies to Bruton's tyrosine kinase

Bruton's X-linked agammaglobulinemia is caused by mutations in a cytoplasmic protein tyrosine kinase termed Bruton's tyrosine kinase (BTK). The protein is expressed in all members of the B cell lineage and is critical for B cell development. The protein consists of several modules, including a pleckstrin homology domain and the Src homology domains SH1, SH2, and SH3. We report here the production of monoclonal antibodies against the pleckstrin homology domain of human BTK. The antibody was produced by immunizing mice with a FLAG-BTK fusion protein. Hybridoma supernatants were screened by ELISA using a GST-BTK fusion protein as the antigen. Selected monoclonal antibodies recognize denatured BTK on Western blots of peripheral blood mononuclear cell lysates. Mouse BTK protein is also detected. These antibodies should be useful in assessing patients with immune deficiency, as well as in studying normal B cell development.