Scanning fluorescence correlation spectroscopy. II. Application to virus glycoprotein aggregation.

Scanning fluorescence correlation spectroscopy is a new approach to measuring changes in the state of aggregation of cell membrane proteins. Measurements of the mean number of aggregates of virus glycoproteins from Sindbis virus and vesicular stomatitis virus agree with the findings of a recent fluorescence photobleaching recovery study on the same systems (Johnson, D.C., M.J. Schlesinger, and E.L. Elson, 1981, Cell, 23:423-431). Sindbis Virus glycoproteins are immobilized and cannot be induced to aggregate further by antibody cross linking. In this study, we find that Sindbis virus glycoprotein is more highly aggregated than vesicular stomatitis virus glycoprotein, which can be patched further with antibody. These measurements demonstrate the potential of scanning fluorescence correlation spectroscopy in studies of aggregation problems in membranes of cultured cells.