STUDIES EVALUATING THE ANTITUMOR-ACTIVITY AND TOXICITY OF INTERLEUKIN-15, A NEW T-CELL GROWTH-FACTOR - COMPARISON WITH INTERLEUKIN-2

Interleukin-15 is a new cytokine that stimulates the proliferation of T cells and other cells of the immune system. Some of the biological p roperties of interleukin-15 overlap that of interleukin-2. Using murin e models, the present studies have shown that interleukin-15, in vivo, is three to four times more potent than interleukin-2 in generating c ytolytic effector splenocytes that lyse YAC target cells. It is approx imately one-third as potent as interleukin-2 in inducing specific cyto lytic cells that lyse allogeneic target cells. Interleukin-15 is appro ximately half as potent as interleukin-2 in suppressing pulmonary meta stasis induced by MCA-205 tumor cells. The dose of interleukin-15 requ ired to induce pulmonary vascular leak in mice is six times higher tha n that required for interleukin-2. These results support the view that interleukin-15 exhibits a therapeutic index that is superior to inter leukin-2. (C) 1995 Academic Press, Inc.