| APRIL (a proliferationinducing ligand), also known as TNFSF13, TALL2, TRDL1, and CD256, is a member of the TNF ligand superfamily (1). It is synthesized as a 32kD proprotein which is cleaved by furin in the Golgi to release the active 17kD soluble molecule (24). Secreted mouse APRIL, which consists almost entirely of a single TNF homology domain, shares 85% and 95% amino acid sequence identity with human and rat APRIL, respectively (2, 3). Both APRIL and its close relative BAFF bind and signal through the TNF superfamily receptors TACI and BCMA, while BAFF additionally functions through BAFF R (2, 5, 6). APRIL binds to heparan sulfate proteoglycans (HSPGs) independently of its binding to TACI and BCMA (6, 7). The interaction with HSPGs induces APRIL oligomerization, and this augments TACI, or BMCAmediated effects (7, 8). HSPGs are also critical for the tumor growthpromoting effects attributed to APRIL (6). APRIL can form bioactive heterotrimers with BAFF, and these circulate in the serum of patients with rheumatic immune disorders (10). TWEPRIL is a bioactive hybrid protein produced by gene splicing. It consists of the intracellular domain, transmembrane segment, and stalk region of TWEAK fused to the TNF homology domain of APRIL (11). TWEPRIL is expressed in monocytes and activated T cells and, in contrast to APRIL, is presented on the cell surface (11). APRIL enhances the proliferation and survival of plasma cells and also promotes T celldependent humoral responses (2, 12, 13). In the context of autoimmune disorders, however, APRIL can inhibit pathologic humoral responses as well as disease progression (14). Its expression by CD4+ T cells inhibits the production of Th2 cytokines and allergic inflammation (15). APRIL levels are elevated in the serum during coronary artery disease (16), and it is also elevated in many cancers primarily due to expression by tumorinfiltrating neutrophils (4, 7, 17). Source: Recombinant protein corresponding to aa96-240 Mouse APRIL/TNFSF13, CHO-derived (Accession NP_001152977). Endotoxin: <0.10 EU/1ug Biological Activity: Measured in a cell proliferation assay using anti-IgM stimulated mouse B cells. The ED50 for this effect is 0.5-3ng/mL in the presence of a cross-linking antibody, Mouse Anti-Hemagglutinin/HA Peptide Monoclonal Antibody Storage and Stability: Lyophilized powder may be stored at -20C. Stable for 12 months at -20C. Reconstitute with sterile buffer or ddH2O. Aliquot to avoid repeated freezing and thawing. Store at -20C. Reconstituted product is stable for 6 months at -20C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer. |
