Retroviruses isolated from cell cultures of human testicular germ cell tumors

Abstract

Human testicular germ cell tumors, which include embryonal carcinoma (EC), teratoma (TM), yolk sac carcinoma (YSC), and choriocarcinoma (ChCa), depict stages of embryogenesis. Differentiation of primitive EC cells is a pathway by which TM, YSC, and ChCa develop. Human EC cells in vitro produce retroviruses, at low frequency, which are morphologically identical to the human placental retrovirus. These viruses have not been previously found in YSC, TM or ChCa cells grown in culture. Due to low virus yield in EC cultures, studies of virion properties have been impeded. We have developed a ChCa cell line by cultivating mixed germ cell tumors in which ChCa was identified histologically. We describe the development of a cell line producing retrovirus particles in markedly higher frequency than those observed with human EC cells.