Transmission electron micrographs provided evidence that fusion of
erythrocytes occurred after treatment with proteolytic enzymes and
polyethylene glycol (PEG). Fusion was not completed until after the
elution of PEG. Scanning electron micrographs indicated that the
outer membranes of adjacent cells were fused. The effects of the
proteolytic enzymes employed in the cell fusion process were examined.
Treatment of erythrocytes with protease alone was found superior to a
combination of trypsin and protease or to trypsin alone.