Endogenous B cell TACI-Short-APRIL signaling

Here we show that TACI-S increases its expression with maturation and colocalizes in the intracellular compartment with the ligand APRIL. APRIL downregulation in human B cells, eliminated class switch. These studies suggest the importance of intracellular APRIL together with TACI-S in maintaining humoral immunity. TACI isoforms, long and short, are coexpressed in human B cells.To analyze independently the functional effects of TACI isoforms, we transduced each one in human BJAB B cell line and analyzed their transcriptional program in resting condition