DOES INTERLEUKIN-2 ENHANCE THE ANTITUMOR-ACTIVITY OF 2-CHLORODEOXYADENOSINE

Background - The present study was designed to compare the influence o f the new purine analog, 2-chlorodeoxyadenosine (2-CdA), with interleu kin-2 (IL-2) on murine leukemias L1210 and P388, Methods - Mice receiv ed tumor challenges (10(6) L1210 or P388 leukemia cells) on day 0 of t he experiment, All treatments were initiated on the following day as d aily intraperitoneal injections, 2-CdA was administered at a dose of 3 5 mg/kg, for 5 days, IL-2 was injected at a dose of 25 mu g/kg or 250 mu g/kg, on the Ist day of the experiment, Drugs were administered alo ne and in combination, The antileukemic effect of the drugs (measured as the increase in life-span: ILS) was assessed as the percentage rati o of the median survival time of the treated group to that of the cont rol group. Results - The results of our study showed that 2-CdA given alone significantly prolonged the survival time of both L1210 and P388 leukemia-bearing mice (ILS 40% and 30% respectively), whereas IL-2 gi ven alone did not change the lifetime of the mice, Survival time of mi ce with P388 leukemia receiving the combined therapy with 2-CdA and IL -2 was significantly prolonged as compared with mice treated with thes e agents separately, In contrast, the addition of IL-2 to 2-CdA did no t prolong the survival time of L1210 leukemia-bearing mice, Conclusion s - The addition of IL-2 to 2-CdA caused the significant prolongation of lifetime of P388 leukemia-bearing mice and did not prolong life of mice with L1210 leukemia.