The aim of this study is to demonstrate the effect of heat treatment of human colon cancer established in nude mice on the cytotoxicity to this tumor by lymphokine-activated killer (LAK) cells linked with chimeric SF-25 monoclonal antibodies (SF-25 Mab) which can recognize a tumor cell surface antigen. Subcutaneous injection of LS180 human colon adenocarcinoma cells into nude mice establishes in these mice a model for human colon cancer. LAK cells were Prepared from PBL of healthy volunteer and SF-25 Mabs were conjugated to LAK cells by polyethylene glycol treatment. Then, for the experiment of hyperthermia, the one thermosensor was placed in the tumor and the other one was inserted into subcutaneous region of opposite site to monitor the temperature at each area, then irradiation of infrared rays were performed in order to heat the tumor area at 43.0ﾟC and also confirmed that irradiation of infrared rays did not heat the non-tumor region of mouse. Using these techniques, human colon cancer bearing nude mice were assigned to as follows : group A ; the mice for the injection of LAK cells conjugated to SF-25 Mab, group B ; the mice for the hyperthermia, group C ; the mice for the single treatment with injection of LAK cells conjugated to SF-25 Mab plus hyperthermia, group D ; the mice for the three time treatments with injection of LAK cells conjugated to SF-25 Mab plus hyperthermia, group E ; non-treated control mice. Then, the tumor size were monitored to evaluate the anti-tumor effects of these treatments.
Results : 1.The intravenous injection of LAK cells conjugated to SF-25 Mab into mice inhibited the tumor growth compared to that of the control group, and 75% of the treated mice were free of detectable tumor.
2.The heat treated mice developed tumor more rapidly than control mice.
3.There were not any difference in the growth of tumor between the mice treated with injection of LAK cells conjugated to SF-25 Mab plus hyperthermia and non-treated mice.