Fighting Off HIV�Without Meds

Scientists are getting closer to figuring out why some people are able to keep HIV at bay without the aid of antiretroviral drugs.

American scientists are trying to replicate the biology of "controllers" — HIV-positive people who manage to keep their viral load down without assistance from medications. In Science magazine, the researchers describe differences in five amino acids contained in a protein that helps the immune system destroy viruses.

"Knowing how an effective immune response against HIV is generated is an important step toward replicating that response with a vaccine," Bruce Walker of the Ragon Institute at Massachusetts General Hospital, one of the lead authors of the paper, told the BBC. "We have a long way to go before translating this into a treatment for infected patients and a vaccine to prevent infection, but we are an important step closer."