New tool for HIV protection

Scientists have developed a new tool that can potentially help protect women from being infected with the human immunodeficiency virus (HIV).

The tool -- a vaginal implant -- decreases the number of cells that the HIV virus can target in a woman's genital tract. 

Unlike conventional methods of HIV prevention such as condoms or anti-HIV drugs, the novel implant takes advantage of some people's natural immunity to the virus.

HIV infects the body by corrupting T-cells that are mobilised by the immune system when the virus enters a person's body.

"We know that some drugs taken orally never make it to the vaginal tract, so this implant could provide a more reliable way to encourage T-cells not to respond to infection and therefore more reliably and cheaply prevent transmission," said Emmanuel Ho, professor at the University of Waterloo in Canada. 

When the T-cells stay resting and do not attempt to fight the virus they are not infected, and the HIV virus is not transmitted between people.  When the T-cells stay resting, it is referred to as being immune quiescent.

However, "what we don't know yet is if this can be a stand-alone option for preventing HIV transmission or if it might be best used in conjunction with other prevention strategies", He added, in a paper appearing in the Journal of Controlled Release.

The implant is composed of a hollow tube and two pliable arms to hold it in place. It contains hydroxychloroquine (HCQ) which is disseminated slowly through the porous material of the tube and absorbed by the walls of the vaginal tract.

The implants were tested in an animal model and a significant reduction in T-cell activation was observed, meaning that the vaginal tract was demonstrating an immune quiescent state, the researchers said.