AIDS vaccine: When natural killers could save lives

A group of researcheer may have found aa AIDS proof - how some lucky individuals never become infected by HIV even if they are chronically exposed to the virus.

French and Vietnamese researchers believe they have shed light on one of the big puzzles of the AIDS pandemic: how some lucky individuals never become infected by HIV even if they are chronically exposed to the virus.

One of the secrets of this remarkable protection lies in so-called natural killer (NK) cells, which are part of the body's first line of defence against microbial invasion, they report in December's issue of an American publication,
Levels of NK were far higher among Vietnamese intravenous drug users who show no sign of infection by the human immunodeficiency virus (HIV) despite long years of exposure to it, the study said.

NK cells, the authors believe, can destroy fellow immune cells that have been infected by the virus and they may also be able to secrete molecules that inhibit HIV infection in the first place.

The study, led by Gianfranco Pancino and Daniel Scott-Algara of the Retrovirus Biology Unit at the Pasteur Institute, compared NK cell functions among 37 long-term, at-risk drug users who had been uninfected; 10 drug users who were infected; and 28 blood donors who had not been exposed to the virus.