HIV-2 genetic library vaccines ineffective in animals.

2003 MAR 5 - (NewsRx.com & NewsRx.net) -- by Michael Greer, senior medical writer - An HIV vaccine containing a "library" of viral antigens has shown disappointing results in animal experiments, researchers in the United States report.

"Immunization using genetic expression libraries may be an improvement over conventional DNA immunization using a single gene because more epitopes are simultaneously presented to the immune system," according to Christopher Locher and colleagues at the University of California at San Francisco.

Unfortunately, an HIV-2 genetic library-based vaccine offered only marginal protection to animals, Locher and coauthors found.

The researchers evaluated the efficacy of an HIV-2 library vaccine in a group of adult baboons. Immunized animals demonstrated HIV-2-specific memory T-cell activity after intravenous HIV-2 challenge, according to the report.

However, virus-specific cytotoxic T-cell responses were muted after challenge in vaccinated baboons, study data showed. Antiviral humoral activity was also limited, with immunized animals carrying low levels of HIV-2-neutralizing antibodies.