Enveloped viruses as model membrane systems: microviscosity of vesicular stomatitis virus and host cell membranes

Abstract

The fluorescence probe 1,6-diphenyl-1,3,5-hexatriene was used to study and compare the dynamic properties of the hydrophobic region of vesicular stomatitis virus grown on L-929 cells, plasma membrane of L-929 cells prepared by two different methods, liposomes prepared from virus lipids and plasma membrane lipids, and intact L-929 cells. The rate of penetration of the probe into the hydrophobic region of the lipid bilayer was found to be much faster in the lipid vesicle bilayer as compared with the intact membrane, but in all cases the fluorescence anisotropy was constant with time. The L-cell plasma membranes, the vesicles prepared from the lipids derived from the plasma membranes, and intact cells are found to have much lower microviscosity values than the virus or virus lipid vesicles throughout a wide range of temperatures. The microviscosity of plasma membrane and plasma membrane lipid vesicles was found to depend on the procedure for plasma membrane preparation as the membranes prepared by different methods had different microviscosities. The intact virus and liposomes prepared from the virus lipids were found to have very similar microviscosity values. Plasma membrane and liposomes prepared from plasma membrane lipids also had similar microviscosity values. Factors affecting microviscosity in natural membranes and artificially mixed lipid membranes are discussed.

Lipid composition and fluidity of the human immunodeficiency virus envelope and host cell plasma membranes.

“…Similarly, for VSV and influenza virus grown in Madin-Darby bovine kidney cells, calculated order parameters were 5-10% greater than those of host cell plasma membranes (43,44). Confirmatory results were obtained from fluorescent spectroscopic analysis of enveloped viruses, indicating that the viral envelopes were significantly more ordered than their host cell surface membranes (39,45,46).…”

The Pseudotypic Paradox

“…Attachment of the M protein to the bilayer brings about some alteration, causing the cellular gp to become relatively less 'soluble' in it, but at the same time, hydrophobic parts of virus gp are more 'soluble' in these modified membranes than in normal cell membranes. Alteration of membranes is indicated by numerous findings (see Barenholz et al, 1976;Barnhart & Ash, 1979;Landsberger & Compans, 1976), showing that virus membranes have a lower fluidity than cellular ones; this is due to some extent to altered proportions of various lipid constituents.…”

Membrane fluidity, capping of cell-surface antigens and immune response in mouse leukaemia cells

“…oooooo oo*o @00. (Barenholz, Moore and Wagner, 1976) and lipid liposomes Van Blitterswijk et al, 1977;Barenholz et al, 1976;Collard et al, 1977). The degree of fluorescence polarization of DPH is related to the microviscosity of the lipid domain in which the probe is embedded, by the Perrin equation, as modified for rotational depolarization of a non-spherical fluorophore (Shinitzky et al, 1971).…”