TNFRSF13B （TACI） is a transmembrane receptor protein found predominantly on the surface of B cells （a significant part of the immune system）. TACI was at first discovered owing to its ability to interact with calcium-modulator and cyclophilin ligand （CAML）. Later on， it was found that TACI plays a key role in humoral immunity by interacting with two members of the TNF family. Also， TACI controls T cell-independent B cell antibody responses， isotype switching， and B cell homeostasis.
