The common antibiotic minocycline, used to treat acne, may also offer a powerful punch against HIV, the virus that causes AIDS. But interestingly, the drug doesn’t target the virus itself – instead, the drug actually affects the immune system cells in which the virus can lie dormant, and stops it from reactivating.

“The powerful advantage to using minocycline is that the virus appears less able to develop drug resistance because minocycline targets cellular pathways not viral proteins,” says study author Janice Clements of Johns Hopkins University.

The benefit of adding minocycline to the mix is that it actually prevents the T cells of the immune system from becoming active and replicating, which the HIV virus requires in order to proliferate and morph into AIDS.

The commonly prescribed anti-HIV combination drug, HAART (which stands for Highly Active Antiretroviral Therapy), can prevent patients from becoming sick over the long term. It keeps the virus resting in a dormant state – but, if doses are missed, the virus can reactivate and cause serious problems. The benefit of adding minocycline to the mix is that it actually prevents the T cells of the immune system from becoming active and replicating, which the HIV virus requires in order to proliferate and morph into AIDS.

To test whether minocycline would work on human T cells, the team looked at isolated immune cells from people with HIV. They treated half with minocycline and left the other half untreated. The researchers found that in the treated cells, there were no detectable HIV virus particles – but in the untreated cells, active viruses were found.

“Minocycline reduces the capability of the virus to emerge from resting infected T cells,” explains another author on the paper, Gregory Szeto. “It prevents the virus from escaping in the one in a million cells in which it lays dormant in a person on HAART, and since it prevents virus activation it should maintain the level of viral latency or even lower it. That’s the goal: Sustaining a latent non-infectious state.”

While the drug minocycline does dampen the activity of the HIV-infected T cells, the even better news is that it does not appear to inhibit the immune system from responding to other kinds of disease – and having a strong immune system is key to HIV patients so that they do not succumb to other infections.

The paper is published in the online edition of the April 15, 2010 issue of The Journal of Infectious Diseases.