Description: The 11H3 antibody reacts with human TACI, also known as tumor necrosis factor receptor 13B. TACI, like BCMA, binds BAFF and April. TACI and its ligands regulate humoral immune responses, activate NF-kB and c-jun N-terminal kinase, and are involved in B cell associated autoimmune diseases. TACI mRNA and protein are found predominantly in B-cells and correlate with BLyS binding in a panel of B-cell lines. TACI interacts with nanomolar affinity with the BLyS-related tumor necrosis factor homologue APRIL for which no clear in vivo role has been described. 11H3 does not block binding of BAFF/BLyS to TACI.