Conformational changes at pH 6 on the cell surface of Semliki Forest virus-infected Aedes albopictus cells.

The mechanism of Semliki Forest virus-induced fusion from within at low pH was studied in Aedes albopictus cells. The fusion was found to occur in at least two steps, namely, a fast initial step which is pH dependent and temperature independent, and a second slower process which is pH independent and temperature dependent. The initiation step induced by low pH exposure constitutes an irreversible conformational change of a protein probably of viral origin located at the cell surface.