Interleukin 1 induction of a serine esterase in a murine T cell line is inhibited by fetal calf serum.

In PC60 cells a serine esterase associated with the cytotoxic granules (BLT-esterase) is induced by interleukin 1 (IL-1). The induction was markedly reduced by fetal calf serum (FCS). A defined culture medium was therefore developed in which the PC60 cells proliferated equally well as in serum-containing medium. In this new medium, IL-1 induced BLT-esterase to much higher levels of activity than in serum-containing medium. When testing IL-1 induction of BLT-esterase with various batches of FCS, no correlation was found between cell proliferation and the responses to IL-1. It was concluded that FCS contains one (or several) inhibitor(s) of IL-1 action.