<prompt> N K cells activity is enhanced by-IL-1TNFIL-2TGP-b  <response>: Interleukin 2 activates NK cells. Interleukin-2 IL-2 is an interleukin, a type of cytokine signaling molecule in the immune system. It is a 15.5 - 16 kDa proteinthat regulates the activities of white blood cells leukocytes, often lymphocytes that are responsible for immunity. IL-2 is pa of the bodys natural response to microbialinfection, and in discriminating between foreign non-self and self. IL-2 mediates its effects by binding to IL-2 receptors, which are expressed by lymphocytes. The major sources of IL-2 are activated CD4 T cells, activated CD8 T cells, NK cells, and dendritic cells Basic Pathology, Robbins. Page no.: 206 