The human B cell activating factor (BAFF) and APRIL(a proliferation inducing ligand) are both type II molecules belonging to the TNF superfamily. They are expressed by non-B cells, and are down-regulated by mitogenic stimulation.2 BAFF and APRIL bind to at least two receptors: TACI (transmembrane activator and CAML-interactor) and BCMA (B cell maturation antigen), both of which are restricted to B cells.3,4 Ligation of these receptors with recombinant BAFF dramatically increases IgM production by peripheral blood B cells 1. Cell surface BAFF can be cleaved to form a soluble trimeric molecule.2
Molecular Structure: A soluble molecule consisting of 151 (VQGPEET…c-term) aminoacids of the extracellular domain of human BAFF fused to the extracellular domain (167aa) of murine CD8 alpha, with a predicted monomeric weight of 38.5 kd. A portion of the extracellular region of BAFF was truncated to amino acid 135 to eliminate a potential protease cleavage site.
Transfectant Cell Line: CHO BAFF(trn)-muCD8 binds to human cell surface TACI/BCMA/BAFFR (8, 9) .
Functional Application: Human BAFF(trn)-muCD8 binds to human cell surface TACI/BCMA (8, 9).
1) Schneider P., J. Tschopp, et al. J. Exp. Med. 1999, 189(11):1747-1756.
2) Shu, H.B., H. Johnson, W.H. Hui. J Leukoc Biol 1999, 65:680-683.
3) Marsters, S.A., A. Ashkenazi, et al. 2000, Curr Biol 10:785-788.
4) Xia, X., H. Hsu, et al. 2000, J Exp Med, 192(1): 137-143.
5) Thompson J.S., C. Ambrose, et al. Science 2001, 293: 2108-2111.
6) Roschke, V, T.S. Migone, et al. J Immunol. 2002, 169: 4314-4321.
7) MacLennan, C.M., C.G. Vinuesa, 2002, Immunity 17:235-238.