Liposomes as Target Membranes in the Study of Virus Receptor Interaction and Membrane Fusion

Abstract

Liposomes represent an excellent model system for the study of virus-receptor interactions and viral membrane fusion processes. The liposomal model system involving lipid-conjugated heparin, described in this chapter, provides a useful tool for the study of virus-receptor interactions. Because many viruses have the capacity to interact with heparan sulfate (HS), the system must be adapted to the study of viruses other than alphaviruses. The assay methods for studying fusion of enveloped viruses with liposomes lacking a specific protein or carbohydrate receptor, described in the chapter, help in examining the role of lipids in the binding and fusion of alphaviruses with target membranes, as well as the pH dependence and the kinetics and extents of those processes. The methods can be readily adapted to the study of fusion of other enveloped viruses, such as flaviviruses. The stringency of the assay methods, including membrane lipid-mixing, as well as content-mixing assays, ensures that the virus-liposome fusion reactions observed represent genuine processes of membrane merging.