B cell-activating factor belonging to the TNF family acts through separate receptors to support B cell survival and T cell-independent antibody formation

S Shulga-Morskaya, M Dobles, ME Walsh… - The Journal of …, 2004 - journals.aai.org
S Shulga-Morskaya, M Dobles, ME Walsh, LG Ng, F MacKay, SP Rao, SL Kalled, ML Scott
The Journal of Immunology, 2004journals.aai.org
The TNF-related ligand, B cell-activating factor belonging to the TNF family (BAFF), is
necessary for normal B cell development and survival, and specifically binds the receptors
transmembrane activator and calcium-modulator and cyclophilin ligand interactor (TACI), B
cell maturation Ag (BCMA), and BAFF-R. Similarities between mice completely lacking BAFF
and A/WySnJ strain mice that express a naturally occurring mutant form of BAFF-R suggest
that BAFF acts primarily through BAFF-R. However, the nearly full-length BAFF-R protein …
Abstract
The TNF-related ligand, B cell-activating factor belonging to the TNF family (BAFF), is necessary for normal B cell development and survival, and specifically binds the receptors transmembrane activator and calcium-modulator and cyclophilin ligand interactor (TACI), B cell maturation Ag (BCMA), and BAFF-R. Similarities between mice completely lacking BAFF and A/WySnJ strain mice that express a naturally occurring mutant form of BAFF-R suggest that BAFF acts primarily through BAFF-R. However, the nearly full-length BAFF-R protein expressed by A/WySnJ mice makes unambiguous interpretation of receptor function in these animals impossible. Using homologous recombination we created mice completely lacking BAFF-R and compared them directly to A/WySnJ mice and to mice lacking BAFF. BAFF-R-null mice exhibit loss of mature B cells similar to that observed in BAFF−/− and A/WySnJ mice. Also, mice lacking both TACI and BCMA simultaneously exhibit no B cell loss, thus confirming that BAFF-R is the primary receptor for transmitting the BAFF-dependent B cell survival signal. However, while BAFF-R-null mice cannot carry out T cell-dependent Ab formation, they differ from BAFF-deficient mice in generating normal levels of Ab to at least some T cell-independent Ags. These studies clearly demonstrate that BAFF regulates Ab responses in vivo through receptors in addition to BAFF-R.
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