Abstract
Fetal brain cells transferred to long-term cell cultures one hour after ENU treatment at a lethal dose (250 mg/ kgw) in vivo became neoplastic after the 18th serial in vitro passage, which was assayed by back transplantation into syngeneic CDF rats. This was preceded by characteristic morphological and biological changes of the cultured cells. During the early culture period, both ENU and buffer treated cultures exhibited monolayers of glial, epithelial and fibroblastic cells. In contrast to control cultures which died within 200 days in vitro, ENU treated fetal brain cells exhibited malignant transformation. The transformed cells (YE2-2) were glial cells with fine processes and they grew without contact inhibition to form pile-up foci. Electron microscopy showed abundant glial filaments in the cytoplasm.
Serological assay by the immune adherence test (IA) and anti-C3 mixed hemadsorption test (C3-MHA), and the qualitative absorption test were performed to analyze the cell surface antigens of the transformed cells. The C3 MHA reactivities of two sera obtained from tumor bearing rats and immunized rats, were absorbed by autologous transformed cells but not by normal fetal brain cells. The result suggests that fetal brain cells obtained a new cell surface antigen in accordance with malignant transformation in vitro.
