Human IL-16 Recombinant Protein. Interleukin 16 (IL-16) is produced primarily by CD4+ and CD8+ T cells and acts as a chemo-attractant for lymphocytes, monocytes, eosinophils, dendritic cells and Langerhans cells. Additionally, IL-16 has been reported to upregulate IL-2 receptor (CD25), induce progression of cells to the G1 phase and suppress HIV & SIV replication.