Cells infected with retroviruses such as HIV can specifically produce viruses at the point of contact between cells, report researchers at Yale University. Ten times more of these particles are found at these cellular poles than elsewhere at the surface of cells, they note in the July 27 edition of PLoS Biology.
This helps explain why viruses spread more efficiently from cell to cell as opposed to when they are floating free in the bloodstream, the researchers explain. "And because the retroviruses are already in cells, they are out of reach of the immune system," adds Walther Mothes, Ph.D., associate professor of microbial pathogenesis at the Yale School of Medicine.
The team also identified a possible weakness in the transmission chain. They found that viruses express a sticky protein that docks with uninfected cells and then attracts viral assembly to these sites. If this adhesion molecule lacked a cytoplasmic tail, then the viral particles did not assemble at the jumping off point between cells.
Dr. Mothes expects many more such targets will be identified as scientists work out the mechanics of cell-to-cell transmission. “We are just opening the door to this whole process,” Mothes said. “It is a black box, and many, many cellular factors have to be involved in making this happen. Our hope is that somewhere down the road we will have a completely new antiviral strategy based on targeting cell-to-cell transmission.”