Studies on the Antigenic Composition of Hamster Tumors Induced by Polyoma Virus, and of Normal Hamster Tissues In Vivo and In Vitro2

Abstract

This study, using antiserums produced in rabbits, the complement-fixation reaction, and the agglutination of sheep red blood cells, concerns 1) the antigenic differences between normal hamster kidneys and polyoma-induced hamster kidney tumors and 2) the antigenic changes that occur when normal cells are grown in tissue culture. Kidney tumors induced in vivo by polyoma virus showed, in comparison with normal kidney, a decrease in kidney-specific antigen and an increase in Forssman (F) antigen concentration. No tumor-specific antibodies were detected in these antiserums prepared in a heterologous host. After short-term culturing in vitro, normal hamster kidney cells underwent changes similar to those found in kidney tumors in vivo, and the data suggest that the decrease of kidney-specific antigen in normal cells in culture occurred before the increase of F antigen. With normal embryo cells, an increase of F antigen, after the cells were cultured for short periods in vitro, was found in hamsters and in mice, an F-positive species, but this antigen was not detected in cultures of embryo cells from the rat, an F-negative species. The results suggest that, regarding the kidney-specific and F antigen, the antigenic composition expressed by a cell may change according to physiological conditions.