U.S. investigators have found a molecule called surfen that can block HIV transmission, Voice of America News reports. The molecule, first described in 1939, is an anti-inflammatory and antibacterial agent that can bond to both HIV and white blood cells.

According to the article, HIV usually struggles to gain a foothold upon entering the body. However, a protein naturally produced in male seminal fluid, called SEVI, makes the virus 100,000 times more transferable than in its normal state. SEVI enhances HIV’s ability to cling to white blood cells and destroy the host immune system.

“What we have found is this small molecule by the name of surfen can block SEVI binding to HIV…and thus interrupt the infectious cycle or the transmission cycle,” said Warner Greene, MD, PhD, director of the Gladstone Institute of Virology and Immunology in San Francisco.

Despite failed attempts to use microbicide creams and gels with anti-HIV agents to prevent transmission, researchers believe surfen could impede infection by binding itself to HIV and the blood cells it targets.

“I think that the concept of using agents that target not only the virus but the host factor propelling the virus infection—I think that combination might produce a therapeutic synergy that could be quite effective,” Greene said.