EFFECT OF TUMOR-EXCISION ON NK CYTOTOXIC ACTIVITY AND FORMATION OF METASTASES OF BOMIRSKI MELANOMA IN HAMSTERS

The growth of transplanted Bomirski melanoma in hamsters is accompanie d by the decrease of natural killer cytotoxic activity and the formati on of metastases. The excision of primary tumors was carried out to ex amine what was the effect of the growing tumor and its metastases on t he host's NK activity. It was found that the excision of primary tumor caused increased NK cytotoxic activity in comparison to that of nonop eriated animals although it was still lower than that of healthy hamst ers. It is concluded that both, a growing tumor and metastases, exert suppressive effects on NK activity and those effects add up. The patte rn of metastases in operated animals was different to that observed in nontreated hamsters.