BOSTON -- A team headed by researchers from Beth Israel Deaconess Medical Center has shown that AIDS vaccines designed to boost the immune response of "killer" T cells were successful in suppressing an unusually virulent strain of the AIDS virus and preventing clinical disease in monkeys, although the vaccine did not prevent infection.

In the study reported in the Oct. 20 issue of Science, all eight animals who received the vaccine remained healthy after being infected with the AIDS virus. The vaccinated animals showed low or undetectable virus levels and no documented clinical disease or death. In comparison, eight animals who received a placebo vaccine showed persistent, high virus levels and significant clinical disease after 140 days, leading to death in half of them.

"We haven't made a vaccine that will prevent AIDS virus infections in humans," says Norman Letvin, M.D., the paper's senior author and chief of viral pathogenesis at Beth Israel Deaconess. "However, the findings in this study suggest that a vaccine might slow disease progression after an infection has occurred and decrease the likelihood of an infected individual transmitting the virus. This could have important ramifications for the AIDS epidemic," says Letvin, also a professor of medicine at Harvard Medical School.

"The findings shed new light on what can be reasonably expected from the candidate AIDS vaccines that are currently under development," say graduate student Xuefel Shen and professor of medicine Robert Siliciano, M.D., Ph.D., both from Johns Hopkins University School of Medicine, in an accompanying perspective article in the same issue of Science. "If the results can be generalized to immunization of humans with HIV-1 vaccines," write Shen and Siliciano, "then we can expect to have vaccines that do not prevent infection with HIV-1 but nevertheless have a significant effect on the course of the disease, potentially improving the quality of life and lifespa
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Contact: Carol Cruzan Morton
cmorton@caregroup.harvard.edu
617-975-6150
Beth Israel Deaconess Medical Center
19-Oct-2000