John Moore of Cornell University in New York and his colleagues are enthused by their finding of a new viral blocker that prevents the virus from burying into human cells. This blocker, in its initial testing in monkeys was found to curb sexual transmission of HIV between monkeys. The new study has backed the belief that microbicides - chemicals that hobble viruses - could act as shields against HIV. This or other microbicides, applied in cream form to the vagina or rectum could save the lives of several women who are not able to protect themselves by monogamy or by using condoms.
Researchers are investigating around 60 potential microbicides that thwart HIV in a variety of ways. Carraguard, a microbicide extracted from seaweeds is already into phase III clinical trials in Southern Africa. Carraguard gums up the surface of virus and vaginal cells to create a physical barrier against infection. Other products being tested, such as Buffergel, instead increase acidity to oust the virus. However, some of the other candidates in this category like the spermicide nonoxynol-9 have been found to increase HIV infection as attack and weaken vaginal cell walls, as well as the target virus.
In the new study, researchers used a human antibody called b12 that binds an HIV coat protein and stops it latching onto cells. They found that when this product was used in monkeys two hours before sex, it prevented infection in 9 out of 12 monkeys, while 12 out of 13 monkeys were infected without the antibody. This antibody, unlike certain other microbicides targets only the HIV virus and does not affect healthy cells.