Inhibition of release of interleukin-2 by vincristine and vinblastine.

The antineoplastic drugs Vincristine (VCR) and Vinblastine (VBL) were tested for their effects on Concanavalin A induced Interleukin-2 (IL-2) release by rat splenocytes. Both drugs were found to inhibit IL-2 release in vitro. This effect was noted at doses of 10 ng/ml and 100 ng/ml in case of VBL and at doses of 1 ng/ml, 10 ng/ml and 100 ng/ml with VCR. The in vivo effect of these drugs was studied by injection into rats three days before culture of splenocytes. This also resulted in inhibition of IL-2 release. The effect was manifested with VCR at doses of 0.1 mg/kg bw and 0.5 mg/kg bw and with VBL at 2 mg/kg bw. These drugs were also tested for their effect on Interleukin-1 (IL-1) release by lipopolysaccharide (LPS) stimulated rat peritoneal exudate cells (PEC's) in vitro. No modulation of the production of IL-1 was seen.