Semen may interfere with HIV gel

Abuja - Semen appears to interfere with microbicide gels to prevent
HIV, possibly explaining why they work in the lab but not in real-life
situations, scientists said Wednesday.
Protein fragments found in semen hamper the work of microbicides
applied to the vagina, said the report in the journal Science
Translational Medicine.
Known as amyloid fibrils, these particles in semen "act like glue to
attach HIV particles to the cell surface and boost viral infectivity,"
said the study led by scientists at the University of California, San
Francisco and the University of Ulm in Germany.
"This effect overpowers the anti-HIV activity of microbicides."
Originally developed for sub-Saharan African
women
These microbicides were originally developed as a way to empower sub-
Saharan African women who may not be able to negotiate condom use
with their partners.
"However, the first generation of microbicides were largely ineffective
or worse, some even leading to increased transmission of the virus,"
said senior author Warner Greene, director of the Gladstone
Institute of Virology and Immunology.
Co-author Nadia Roan, assistant professor-in-residence in the
Department of Urology at the University of California, San
Francisco, said the latest research builds on earlier studies.
"We've shown previously that semen enhances HIV infection, but this
is the first time we've shown that this activity markedly reduces the
antiviral efficacy of microbicides."
The effect was the same among all microbicides tried in the study
except Maraviroc, which is under consideration for use as a
microbicide and is used currently as a treatment for HIV/AIDS.
It acts differently than microbicides that attack HIV itself, and
instead binds to an entry co-receptor on host cells to stop the virus
from entering the cell.
"The results indicate that Maraviroc is a promising microbicide
candidate, and suggest that future microbicides should be tested in
vitro in the presence of semen," said the study.
More work is needed to develop a "compound or cocktail of drugs that
targets both the HIV virus and these amyloid fragments and to test
its effectiveness," said senior author Jan Munch from the University
of Ulm.