Molecular biology of interleukin 2

Study of the lymphokine interleukin 2 (IL2) began with several diverse qualitative observations in the middle 1970s. Rationalization of early work led to a focused program of research involving a number of laboratories. This recently culminated in the molecular description of both murine and human IL2. The glycoprotein, containing about 16 000 daltons of protein, is secreted in response to activators of T helper lymphocytes. A number of complex immune responses is stimulated by pure, recombinant IL2. The induction of IL2 and other lymphokines is apparently specific, in that only a small subset of proteins shows altered expression in the response. Moreover, the immunosuppressive agent cyclosporin A specifically inhibits the induction of mRNA for IL2 and certain other lymphokines, without affecting the expression of the majority of other proteins. Understanding of IL2 and its biological context has recently been enhanced by an intense activity on the part of biotechnology companies.