"Killer T-cells" give Gambian sex-workers the cutting-edge on HIV
Aids Analysis Africa 5(2): 3
1995
ISSN/ISBN: 1016-8974 PMID: 12288603 Document Number: 288170
The results of a Gambian study may explain how 30 women out of 424 prostitutes in Nairobi, Kenya, remain uninfected with human immunodeficiency virus (HIV) after 5-6 years of prostitution, in spite of a prevalence rate of 90% in city sex workers. The Gambian study also found a group of uninfected sex workers who had been repeatedly exposed to the virus; researchers believe killer T-cells are responsible. Sarah Rowland-Jones of the Institute of Molecular Medicine at the University of Oxford, at the Medical Research Council's clinic in Fajara, Gambia, studied 6 female sex workers who had been prostitutes for more than 5 years and rarely practiced safe sex. Approximately 30% of sex workers in the region are infected with HIV; this suggests that the workers were exposed to the virus once or twice per month over 5 years. 3 of the women had high levels of killer T-cells; 2 had some level. Killer T-cells, or cytotoxic lymphocytes, seek out and destroy virus-infected cells; they are particularly effective against viruses (like HIV) which are passed cell to cell without passing through the bloodstream where they would be attacked by antibody. Although they are found in people with HIV, in most cases they are overwhelmed by the virus. One hypothesis in these uninfected cases is that the women were first infected with HIV-2, a less aggressive strain dominant in West Africa; built up an immunity to it; and then fought off the infection with HIV-1 that arrived later in Gambia. Rowland-Jones will next determine the levels of killer T-cells in the uninfected Nairobi sex workers; her results should be available in April 1995.