Effect of neuraminidase on electrophoretic mobility and immune cytolysis of human uterine cervix carcinoma cells

Abstract

The electrophoretic mobility of human uterine cervix carcinoma cells at pH 7.2 was found to be 0.89 μ/sec/v/cm at 25®C, while normal human cervix cells had a mobility of 0.58 μ/sec/v/cm. Treatment of the carcinoma cells with neuraminidase for 30 min reduced the electrophoretic mobility to 0.46 μ/sec/v/cm. Neuraminidase liberated more N-acetyl-neuraminic acid from carcinoma cells than from normal cells. Immune cytolysis of carcinoma cells by lymphocytes was studied by means of. 51. Cr-release technique. Autologous and homologous lymphocytes from carcinoma cervix patients had a lytic effect on carcinoma cervix cells; and the cytolysis was increased about two-fold when the malignant cells were treated with neuraminidase. Homologous lymphocytes from healthy donors had comparatively little cytolytic action on malignant cells. Autologous lymphocytes had virtually no effect on normal cervical cells and neuraminidase treatment did not affect their susceptibility to lymphocytes. Autologous and homologous serum from cancer patients had a cytolytic influence on malignant cells; but normal serum was without effect. Although calcium chloride reduced the negative surface charge on the malignant cells, as gauged by their electrophoretic mobilities, no increase in the cytolysis of carcinoma cells by autologous lymphocytes was observed in the presence of charge-reducing concentrations of calcium chloride. These results suggest the possibility that in the case of cervical carcinoma, sialic-acid-containing moieties partially mask tumor-specific antigens on cell surface and prevent their recognition by immunologically competent cells of the host.