Recombinant Bovine IL-16IL-16 was originally described as a factor that could attract activated T cells in humans, it was previously called lymphocyte chemoattractant factor (LCF). IL-16 is synthesized as a precursor (pro-IL-16), which is a substrate for caspase 3, the central effector of apoptosis. The cleavage of pro-IL-16 by caspase 3 releases the biologically active form of the molecule. IL-16 is an immunomodulatory cytokine released at the inflammatory site. Through its interaction with CD4, IL-16 acts as a chem oattractant for CD4 immune cells including T-cells, monocytes and eosinophils. IL-16-expressing cells include mononuclear phagocytes, CD4 and CD8 T-cells, eosinophils and mast cells.