Disease‐related lymphocyte cytotoxicity in rats bearing transitional cell carcinoma of bladder. effect of immunomodulators

Blood lymphocytes from rats bearing transitional cell carcinoma (TCC) of the bladder were studied for their cytotoxicity in vitro against xenogeneic YAC‐1 target and against syngeneic TCC cells. Control lymphocytes were obtained from age and sex‐matched syngeneic rats. The following differences were observed: (I) lymphocytes from TCC‐bearing rats were cytotoxic to syngeneic TCC target cells whereas those from control rats were not; (2) lymphocytes from TCC‐bearing and control rats were cytotoxic to NK sensitive YAC‐I cells; however, NK cells from TCC‐bearing rats were more adherent to nylon wool‐columns than NK cells from control rats. The adherent and non‐adherent cells from TCC‐bearing rats were both cytotoxic to syngeneic TCC target cells. Levamisole treatment of effector cells from TCC‐bearing rats did not affect the NK activity, yet it increased the cytotoxicity of non‐adherent cells on TCC target cells. Treatment of the adherent cells with poly‐l:poly‐C increased slightly their NK activity on YAC‐I cells and their anti‐TCC cytotoxicity. However, a marked increase in the cytotoxicity by both adherent and non‐adherent cell fractions was observed on TCC target cells pretreated with poly‐l:poly‐C. A disease‐related cytotoxicity of lymphocytes from rats bearing TCC has been observed. Treatment of TCC target cells with poly‐l:poly‐C increased their susceptibility to lysis by the activated effector cells.