Cytotoxicity of Subpopulations of Splenic Cells from Normal and Fibrosarcoma - Bearing Mice towards Syngeneic Tumour Cells

Abstract

The nonadherent splenic cells from normal and tumour-bearing (mouse fibrosarcoma-MFS) Swiss mice were divided into 6 subpopulations on Percoll step density gradient and characterised. For the determination of their cytotoxicity towards syngeneic MFS cells and their electrophoretic mobility (EPM), the splenic cell populations were pooled to form 2 broad groups: a lower-density group (density of saline to just less than 1.069 g/ml) and a higher-density group (1.069 to just less than 1.087 gm/ml). In general, the splenic cells from mice bearing 10- to 11-day-old MFS tumours differed in certain characteristics from those of normal mice in that they showed an increase in the following: proliferation, heterogeneity, with appearance of large cells (greater than 70 mu2); cells with a lower density (less than 1.069 g/ml); cells with a lower (less than 0.85 micron/sec/Volt/cm) anodi cEPM. The cytotoxicity studies revealed that: a) the lower-density splenic cells of both normal and tumour-bearing mice were more cytotoxic than the higher-density splenic cells; b) the lower- and higher-density splenic cells of tumour-bearing mice were more cytotoxic than the corresponding cells of normal mice. These findings indicate that the splenic cells of mice with a lower EPM and a lower density are the main contributors of cell-mediated cytolysis of a subpopulation of MFS cells.