Once a virus infects a cell, neighboring cells are likely to become infected by interactions that are dependent on the cell and the virus in question. For example, cell-to-cell spread is facilitated in HIV by viral synapses, which also allow for escape from neutralizing antibodies. Low-level drug inhibitors are able to suppress infection if applied before the first cell is infected, but not after, demonstrating the lower sensitivity towards antiviral therapy-induced by this cell-to-cell transfer method.
