Virus Meets Liposome

Abstract

Sendai virus was the first virus to encounter liposomes. Gangliosides when incorporated into liposomes act as Sendai virus receptors even at 0–4°C. When receptor-containing liposomes are incubated with virus at 37°C, they envelop the virus. At 37°C liposomes also fuse with Sendai virus membrane.

Virus binding initially involves weak adhesion, which may allow the virus to “browse” the cell, and which is followed by adhesion strengthening. MicrogrΔpHs of Sendai virus fusion with liposomes after one minute at 37°C indicate that fusion occurs at the very curved leading edge of the region of the liposome enveloping virus. A model of fusion is proposed that emphasizes the role of the curvature and membrane tension in this localized region of “host” membrane. The curvature assists close approach and destabilizes the outer monolayer. The proposed intermediates are consistent with the “stalk” hypothesis.