Lymphocyte Chemoattractant Factor
IL-16 is a pleiotropic cytokine that functions as a chemoattractant, a modulator of T cell activation, and an inhibitor of HIV replication. The signaling process of IL-16 is mediated by CD4. The product of this gene undergoes proteolytic processing, which is found to yield two functional proteins. IL-16 functions exclusively attributed to the secreted C-terminal peptide, while the N-terminal product may play a role in cell cycle control. Caspase 3 is reported to be involved in the proteolytic processing of this protein. Two transcript variants encoding different isoforms have been found for this gene. IL-16 stimulates a migratory response in cd4+ lymphocytes, monocytes, and eosinophils. Also induces t-lymphocyte expression of interleukin 2 receptor, ligand for cd4.