During replication, many viruses trigger certain lipid molecules that are normally found only on the inner layer of the cell membrane to spread into the outer layer. An antibody that looks for these lipids on cell surfaces can selectively pick off infected cells.
Philip Thorpe of the University of Texas Southwestern Medical Center in Dallas and his colleagues have shown this with the antibody bavituximab, which seeks the lipid phosphatidylserine. They cured guinea pigs with lethal Pichinde virus infections and mice harbouring deadly cytomegalovirus. The former virus is a model for the Lassa fever virus, a potential bioterror agent.