Augmentation of interleukin-2 release by cytochalasins

Augmentation of mitogen-induced release of the T cell lymphokine interleukin-2 (IL-2) occurred using several cytochalasins in coculture with a T cell lymphoma line (JM) or with purified T cells. When added concurrently with mitogen, cytochalasins had no apparent negative effect either on the ability of mitogen to signal IL-2 production or on the total amount produced. Use of cytochalasins that affect submembranous actin in peripheral lymphocytes established a link between cytoskeletal alterations and lymphokine release, although direct membrane perturbation cannot be excluded. These data indicate that an intracellular pool of IL-2 may accumulate in both T cell lines and in purified peripheral T cells and that maintenance of that pool may be affected by alterations of the cytoskeletal elements. Cytochalasins not only increased IL-2 release, but could substitute for phorbol myristic acetate (PMA) in supporting mitogen-signaled IL-2 production. We interpret these data also to indicate that cytoskeletal attachment to the surface molecules that signal IL-2 production is not needed for the activation.