A study on the isoforms of transmembrane activator and cyclophilin ligand interactor (TACI) in human B cells

Human B cells use cytokines in order to communicate amongst themselves and other members of the immune system. Amongst the various ligands and receptors involved in cytokine signaling, the tumor necrosis factor (TNF) ligand and receptor families are quite important due to their role in determining cell life and death. Trans-membrane activator and cyclophilin ligand interactor (TACI) is a member of this family and is mutated in 8% of common variable immunodeficiency (CVID) patients, a primary immunodeficiency. TACI has 2 isoforms in humans only and it is unclear which isoform has preferential expression in diverse B cell populations. To this end, we examined peripheral blood mononuclear cells (PBMCs), multiple myeloma cell lines and Hodgkin's disease cells and found that both the longer and the shorter isoform of TACI are expressed. Further studies will confirm whether one isoform or the other exerts greater control on receptor function.