A team of American scientists has discovered a molecule that could block transmission of HIV, the virus that causes AIDS.  Researchers say the preventive agent might someday be used in a topical cream to help prevent infection with the deadly virus.

Scientists have long known that after the HIV virus enters the human body, it struggles to gain a foothold.  But a naturally occurring protein in the male's seminal fluid, called SEVI, makes the virus 100-thousand times more infectious than it would otherwise be, aiding HIV's ability to attach itself to its victim's white blood cells and in so doing, destroy the host immune system.

Now, US investigators have discovered that a molecule called surfen can interfere with SEVI's action. Warner Greene is the director of the Gladstone Institute of virology and immunology in San Francisco, California, where the test-tube studies have been conducted.

"What we have found is this small molecule by the name of surfen can block SEVI binding to HIV virions [viruses] and thus interrupt the infectious cycle or the transmission cycle," said Warner Greene.

Greene says surfen, first described by scientists back in 1939, is both an anti-inflammatory and anti-bacterial agent. He explains that surfen prevents infection by binding itself to both the AIDS virus and to the blood cells targeted by HIV.
Research into topical medications know as microbicides - creams and gels containing anti-HIV agents that are usually applied before sexual intercourse - has been disappointing, and the method has not been effective preventing the spread of the AIDS virus.  But Greene is hopeful surfen will make a difference.

"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 [enhanced interaction] that could be quite effective," he said.

Greene says similar so-called "cocktail" therapies have proved to be effective weapons in treating AIDS patients.

"Just as we use combination anti-retroviral therapy to treat patients with HIV infection, we might be able to prevent transmission of HIV using combination microbicides," said Greene.

Warner Green and colleagues describe surfen's anti-AIDS properties in the current issue of  the Journal of Biological Chemistry.