Electrofusion of IBRS2 cells and the study of their fusion process.

IBRS2 epithelial cells in monolayer culture fused at a very high frequency when exposed to high-voltage electric pulsing fields. Exposure to four repetitive electric pulses of about 1.7 kilovolts per centimeter with a duration of 100 microseconds caused more than 90 percent of the cells to become fused (multinucleate) when 1 millimolar magnesium was present in the pulsing medium. Magnesium and calcium ions in the pulsing medium had a very strong effect on the electrofusion of IBRS2 cells. Magnesium could increase not only the electrofusion yield but also the stability of the cells under the conditions of electrofusion. In contrast, calcium inhibited electrofusion and decreased the stability of the cells. Careful microscopic observation revealed the electrofusion of IBRS2 cells to be very complex, dynamic process undergoing many interesting changes. A possible explanation for the process and mechanism of electrofusion of IBRS2 cells was proposed in agreement with the experimental observation.