Embryoid bodies cultured in in vivo diffusion chambers show reduced tumorigenicity while retaining expression of F9 antigens

Embryoid bodies of the mouse teratocarcinoma OTT6050 were dissociated into single cells and cultured in diffusion chambers implanted into the peritoneal cavities of mice. The syngeneic host mice, into which the cells of embryoid bodies cultured in the diffusion chambers had been injected, survived much longer than those which received the original cells of embryoid body. But in the case of the F9 cells, obtained in the same culture conditions, only a slight decrease in tumorigenicity was observed. By contrast, the F9 antigenic expression was observed on both F9 and embryoid body cells cultured in diffusion chambers. Judging from the determination of adult-type antigenic expressions, the differentiation of the cells in chamber was negligible. These results suggest that the tumorigenic activity of the embryoid body cells cultured in vivo in a diffusion chamber is almost suppressed, but that they continue in an undifferentiated state.