University of Pennsylvania researchers have uncovered an important step in how herpes simplex virus, HSV-1, uses cooperating proteins found on its outer coat to gain entry into healthy cells and infect them. Further, the study’s authors say, they have demonstrated the effectiveness of monitoring these protein interactions using biomolecular complementation.

By adulthood, most people have suffered at least one bout of painful cold sores brought on by the Herpes simplex virus 1, also known as HSV-1. After the initial infection, the virus usually remains in the body, hiding out in nearby nerve cells where the victim's immune defenses cannot reach it, causing no symptoms at all.