Fibers in Semen Help HIV Penetrate Cells

Fibers in Semen Help HIV Penetrate Cells
THURSDAY, Dec. 13 (HealthDay News) -- In a discovery thatperplexes HIV experts, an international team reports that tiny fiberscommonly found in semen drastically enhance the ability of the virus to doits damage.
According to a study in the Dec. 14 issue of Cell, the fiberscapture the virus and then ferry it to target cells, increasing itsability to infect someone by more than 50 times in some cases and morethan 100,000 times in others.
The findings could help scientists better understand how AIDS istransmitted. But Rowena Johnston, director of research with the Foundationfor AIDS Research (amfAR), noted that the value of the research islimited, because it doesn't "necessarily reflect transmission in the 'realworld.' "
"This is intriguing, and it's worth further investigation," saidJohnston. "But there's nothing yet that makes me have a 'Eureka'moment."
While scientists have long known about the basics of AIDS transmission,it's not clear why the virus travels more easily through some routes thanothers.
For example, male-to-female sexual transmission is usually more commonthan the other way around but not always. And it's also not clear why thevirus has become so prevalent even though it has a tiny presence inblood.
In the new study, led by a German team, scientists tried to figure outif components of human semen might affect transmission of the AIDSvirus.
"We were not expecting to find an enhancer and were even more surprisedabout the strength," study author Dr. Frank Kirchhoff, of the UniversityClinic of Ulm, said in a statement. "Most enhancers have maybe a two- orthreefold effect, but here, the effect was amazing, more than 50-fold,and, under certain conditions, more than 100,000-fold. At first, I didn'tbelieve it, but we ran the experiment over and over, always with the sameresult."
Dr. Jeffrey Laurence, a professor of medicine and director of theLaboratory for AIDS Virus Research at Weill Medical College of CornellUniversity, said there could be something similar at play in cervicalfluid that affects transmission. "In a lot of situations in the realworld, women transmit HIV quite easily...," Laurence said.
He added that many other factors affect transmission of HIV, frombodily abrasions to menstrual cycles and use of oral contraceptives.
Could this latest finding bring scientists closer to an AIDS vaccine?Laurence, who thinks a vaccine is decades off, is doubtful. Prevention,however, might be another matter.
Laurence said it might be possible to develop an "antidote" for thevirus-boosting powers of semen and put it in a microbicide that peoplecould use before sex.
More information
Learn more about the basics of AIDS from aids.org.