Phenotypic expression of malignancy in hybrid and cybrid mouse cells.

This study has been directed toward the effect of cytoplasmic transfer on the expression of marker properties in hybrid cell systems. Conventional hybrids between two nucleated cells were constructed between tumorigenic and nontumorigenic cells. Cytoplasmic hybrids, or cybrids, were constructed between enucleated chloramphenicol resistant (CAP R) donor cells (cytoplasts) and nucleated recipient cells. Clear-cut evidence for the cytoplasmic transmission of CAP resistance was obtained. Although cytoplasmic transfer had no effect on tumorigenicity or growth in soft agar, preliminary evidence was found that saturation density of the recipient cells could be altered by cytoplasmic addition in cybrids.