The effects of
chemotherapy or local irradiation on lymphokine-activated killer (LAK) cell accumulation into
tumor sites were investigated. Lymphokine-activated killer cells labeled with
111In-oxine were injected into the caudal vein of C57BL/6 mice that had been previously transplanted with 3LL
cancer. An adoptive transfer of LAK cells was carried out 4 days
after treatments. Twenty-four hours after the transfer,
tumor tissues were excised, and the accumulation of labeled LAK cells in the
tumor was measured. In two different experiments, LAK cell accumulation in
tumor in the nontreated group was 2.15% and 1.58% of the administered dose per gram of tissue. The accumulation in the groups of mice treated with
cyclophosphamide,
nimustine hydrochloride, or
Adriamycin increased fourfold (7.38% dose/g, 6.61% dose/g), threefold (6.47% dose/g) and twofold (4.46% dose/g), respectively, as compared with the nontreated group. These agents induced significant
tumor regression. In the group treated with
bleomycin, which showed no significant effect on
tumor growth, LAK cell accumulation in
tumor remained unaltered (1.57% dose/g). However, the group treated with local irradiation, which induced significant
tumor reduction, showed no increase in LAK cell accumulation into
tumors. These results suggest that some
antitumor drugs enhance LAK cell accumulation into
tumor sites and that this increase is due to
tumor modification by
antitumor drugs.