Increased Susceptibility to Mycoplasma Infection of SV40 Transformed Human Amnion Cells 1

Abstract

Summary

The effects of infection with mycoplasma (strain HT, mycoplasma fer-mentans) on cell morphology and growth were different for primary amnion cells and for SV40 transformed amnion cells before and after “crisis.” Post-“crisis” cells showed distinctly more growth reduction, cytopathic changes, and cell destruction than pre-“crisis” cells, although cell-associated mycoplasma was present in similar, high amounts. Pronounced resistance of primary amnion cells was correlated with a very low amount of cell-associated mycoplasma, even at high concentrations of free mycoplasma. The presence of the primary cells supported mycoplasma propagation, as determined in the culture fluid, much less than either pre- or post-acrisis” cells. There is indication that the primary cells may be responsible for a mechanism of inhibition of mycoplasma propagation. It is suggested that the differences in mycoplasma susceptibility among the three cell types are related to their different state of in vitro malignancy, and may serve as useful criteria in further studies of the changes occurring after the virus transformation.