Do some lubes offer more protection against HIV than others? Preliminary work by researchers at the University of Texas Medical Branch ( UTMB ) , Galveston suggests that might be the case. The study is published in the July 20 edition of AIDS Research and Human Retroviruses.
A team led by Dr. Samuel Baron previously had shown that compounds in human saliva attack leukocytes, white blood cells that may be infected with HIV, as well as cell-free HIV in semen. He reasoned that perhaps some other compounds could mimic the anti-HIV properties of saliva.
We seldom give it much thought, but saliva is the immune system's first line of defense against a continuous assault by germs from the food we eat, the people we kiss, even the air that we breath. Saliva probably is the reason why transmission of HIV through oral sex seems to be much more difficult than through other forms of sex.
The UTMB team started by testing what was out there, 22 sexual lubricants that can be purchased over-the-counter. They eliminated those that may be irritating because the accompanying inflammation draws the immune system's CD4 cells, the type that HIV especially likes to infect.
Other researchers had long established that the common spermicide nonoxynol-9 ( N-9 ) could kill HIV in the test tube. But in regular use it can cause vaginal irritation. Last year the Population Council's David Phillips showed that N-9 was highly toxic in the rectum. He found that when using lube with N-9, the mucosal epithelia, that single layer "skin" of cells that lines the rectum and acts as a barrier to disease, "was coming off in great sheets of cells," leaving the body especially vulnerable to HIV infection.
So the UTMB group dumped products with N-9. Through a complex series of laboratory tests, they found that three products...Astroglide, Vagisil, and ViAmor...significantly inhibited HIV replication and were not irritating. The protective effect began within the first five minutes of use, and lasted for at least eight hours.
"We have identified two of the components that seem to be the active material," said Baron in a telephone interview. "It's part of the slippery stuff, the things that make them lubricating." He was purposefully vague as a scientific paper is being prepared for publication.
"The mechanism of action is probably disrupting or inactivating the surface membrane of both the virus itself and the infected cell," he said. N-9 works the same way, but these products have none of the irritating effects associated with N-9.
Baron said the compounds "are so inexpensive that they are perfect for third world countries." He has begun conversations with Family Health International about conducting a large trial to see if the same anti-HIV properties carry over in humans and can provide added protection from infection. That trial will cost about $3 million.
So don't go throwing your condoms away just yet. This is just a starting point for more research and trials. Remember that N-9 looked good in the test tube too, but in real life it ended up being worse than regular lubricant. These products will have to go through trials in humans to determine if the benefits seen in the lab carry over into the bedroom.
