Transformation of human embryo cells with the use of cell-free extracts of a human rhabdomyosarcoma cell line (HUS-2): brief communication.

Cell-free extracts of the human rhabdomyosarcoma cell line HUS-2 caused the transformation of human embryo fibroblasts. This transformation included morphologic alteration, karyotypic change, and an increase in culture longevity. With the use of sex markers, multiple karyotypes confirmed that the human embryo fibroblasts were transformed, and the use of cell-free material further suggested the presence of a transforming virus. RNA-dependent DNA polymerase activity in a particle with a specific gravity of 1.16 g/cm3 indicated the presence of an RNA type C virus. Evidence also suggested that the known mammalian type C viruses, routine cytopathic effect-inducing viruses, or mycoplasma were not the agents responsible for the transformation. That both the donor (HUS-2) and converted (HUE-T) cell lines cross-reacted with antisera prepared against HUE-T indicated a common antigen arising in the process of conversion of HUS-2 cells to HUE-T cells.