Interleukin 2: the molecule and its function.

IL2 plays an essential role in triggering proliferation of activated T cells, a response mediated by interaction of the factor with a high-affinity membrane receptor. IL2 also influences a number of other cellular responses, including natural killer cell activity and antibody secretion. Thus, directly or indirectly, IL2 has the properties of both a growth factor and a differentiation signal. Both IL2 and its receptor have been purified to homogeneity and extensively characterized at the molecular level. In this review, Richard Robb discusses the current biochemical understanding of IL2 and its receptor and new information relating to its role in cellular responses.