RESUMEN
The changes of the growth characteristics and surface ultrastructure during longterm passages of Wg3h cells that have been transfected with PSV_2-neo (Wg3h-neo) were studied. The results showed that the growth and DNA synthesis rate were evidently higher in the transfected cells than in the parental wg3h cells. The saturation of the transfected cell growth density was also increased, but neither the parental and transfected cells formed cell colony in soft agar medium nor tumor growth in nude mice. There was no significant differences in morphology between the two cell types under light microscopy, however much more microvilli were seen on the transfected cell surface under scanning electron microscopy. Southern blot hybridization analysis indicated that the PSV_2-neo plasmids were integrated into the genome of the target cells. Our results demonstrated that the transfected cells remained as nonmalignant cells although some changes of their growth characteristics and surface ultrastructure appeared.