Protection by attenuated simian immunodeficiency virus in macaques against challenge with virus-infected cells

Abstract

A vaccine against AIDS will probably have to protect against challenge both by viable virus-infected cells and by cell-free virus. Eight cynomolgus macaques infected with attenuated simian immunodeficiency virus (SIV) were challenged (four each) with cell-free and cell-associated SIV. All were protected, whereas eight controls were all infected after challenge. These findings show that live-attenuated vaccine can confer protection against SIV in macaques. Extrapolation to human beings will require extensive evaluation of the safety of attenuated retroviruses. Alternatively, the mechanism of this potent protection must be understood and reproduced by less hazardous means.

PIP: That HIV-1 may be transmitted by virus-infected cells as well as by free-floating virus particles make the development of a vaccine against AIDS particularly challenging. The infection of monkeys (macaques) with simian immunodeficiency syndrome (SIV) is a model for HIV infection in man. The authors report findings from a study in which eight cynomolgus macaques infected with attenuated SIV were challenged with cell-free and cell-associated SIV. All were protected, while eight controls were infected after challenge. The researchers found that live-attenuated vaccine can confer protection against SIV in the monkeys. Applying these findings to vaccine development for humans will, however, require extensive evaluation of the safety of attenuated retroviruses. Otherwise, the mechanism of protection must be understood and reproduced by more safe means.