[Augmentation of LAK cell-accumulation in tumor tissue and its therapeutic effect after chemotherapy]

We investigated the therapeutic effects of a combination of chemotherapy with adoptive immunotherapy on BMT-11 fibrosarcoma in C57BL/6 mice. Although no significant therapeutic effects were brought about by CY alone or LAK.rIL-2 alone, CY plus LAK/rIL-2 brought about significant therapeutic effects such as a reduced proportion of dead mice (63%) and prolongation of the mean survival times of dead mice (64.4 days). We transferred radioactive 111In-labeled effector cells into untreated and CY-treated tumor bearing mice. LAK cell-accumulation (% dose/g) at the tumor site was only 2.7% in untreated mice and 19.7 in CY-treated mice. On the other hand, CTL.rIL-2 therapy exhibited significant therapeutic effects by itself. The accumulation of CTL was 9.1% in untreated tumors and only slightly enhanced by CY-chemotherapy. These results suggest that the therapeutic effects of adoptive immunotherapy depend on the accumulation of transferred effector cells at the tumor site and are augmented by the enhanced accumulation of effector cells after chemotherapy.