The enhancement of tumor cell susceptibility to macrophage binding and cytolysis by p-aminobenzoic acid-N-xyloside sodium salt (K-247).

The enhancement of tumor cell susceptibility to macrophage binding and cytolysis by the pretreatment of tumor cells by p-aminobenzoic acid-N-xyloside sodium salt (K-247) was investigated in the C3H/He mouse-syngeneic tumor system. Binding and cytolytic activities of Corynebacterium parvum-activated macrophages were significantly enhanced when target MM-102 and MH-134 cells were pretreated with K-247 at doses of 200 or 400 micrograms/ml, while thioglycollate-elicited macrophages showed much lower binding and lytic activities against K-247 pretreated target cells. No enhancement of these activities were observed when target cells were pretreated with D-xylose, which had no anti-tumor activity. Furthermore, in a binding assay a significant reduction of macrophage binding to target cells by the K-247 pretreated cold competitors was observed. It is suggested that target cell susceptibility to macrophage cytolytic activity might be enhanced by pretreatment with K-247, involving an initially increased target binding.