Erythrocytes from Yoshida ascites sarcoma-bearing rats have reduced surface charge: the effect of tumor products.

Erythrocytes from the circulation of rats bearing intraperitoneal Yoshida ascites sarcoma, as well as the red cells contaminating the tumor fluid, exhibit higher concanavalin A (Con A)-mediated agglutination than the cells from normal animals. Two proteins have been purified earlier from the ascites fluid that can impart high agglutinability on the cells in vitro. We report here that the erythrocytes from the tumor-bearing rats exhibit reduced electrophoretic mobility compared to the cells from normal animals (P < 0.001), which correlates with the increase in their Con A-agglutinability (r = 0.998). The two purified proteins also cause reduction in the electrophoretic mobility of erythrocytes (P < 0.01). Thus the modification of the host cell surface observed in tumor-bearing rats arises due to non-specific binding of tumor products that reduce the host cell surface charge.