Neoantigens on chemically transformed cloned C3H mouse embryo cells

Using an in vitro cytotoxicity test for cell-mediated immunity and a membrane immunofluorescence test, the appearance of new antigens was detected on cloned C3H mouse embryo cells undergoing malignant transformation in vitro following treatment with 3-methylcholanthrene or 7,12-dimethylbenz[a]anthracene. These antigens were recognized by specifically immunized syngeneic mice and were individually unique for each of eight chemically transformed cell lines tested, all of which were derived from the same control parent clone. Very few cross-reactions were seen between lymphoid cells or antibody from mice immunized against a given cell line and target cells of other cell lines. New antigens could not be detected on two spontaneously transformed lines. Lymphoid cells from multiparous pregnant or embryo-immunized cmice were used to search for fetal antigens on control and transformed cells. Fetal antigens were detected on seven of the chemically transformed cell lines and one spontaneous transformant, but not on nontransformed control cells. It is concluded that individually specific new antigens are characteristic of chemically transformed cells, but the expression of fetal antigens may be a more common feature of transformed cells in general.