Release of membrane constituents following polyethylene glycol treatment of HEp-2 cells.

HEp-2 cell monolayers were treated with 40% polyethylene glycol for 5 min which resulted in fusion during the subsequent incubation period. A loss of cell membrane components was detected in the polyethylene glycol-treated as well as phosphate buffer/saline-treated control cells, however the polyethylene glycol-treated cells released nearly twice the amount of [14C]acetate-labeled material and [3H]glycerol-labeled lipids into culture fluids than the control cells. It was further detected that the polyethylene glycol-treated cells released only approximately half the amount of protein, glycoprotein, and glycolipid as the control cells. These results suggest that polyethylene glycol exerts a differential mode of action against cell surface components and causes the treated cells to release membrane components rich in lipids but relatively low in protein and carbohydrate-containing components.