DNA vaccine against HIV: starting research on volunteers

Researchers at Emory University and GeoVax Labs, Atlanta, working under the guidance of Dr. Harriet L. Robinson, have created a vaccine that protects monkeys from infection with the Simian Immunodeficiency Virus (SIV) with numerous episodes of infection for more than three years.

The vaccination protocol consisted of two primary vaccinations (at 0 and 2 months of life) and two auxiliary vaccinations (at 4 and 6 months). The primary vaccination consisted in the introduction of DNA expressing SIV proteins and granulocyte macrophage colony stimulating factor (GM-CSF) - granulocyte macrophage colony stimulating factor, GM CSF. The latter is a natural protein that stimulates the development of immune reactions and, accordingly, increases the ability of the vaccine to launch the production of specific antibodies capable of destroying viral particles before they penetrate into target cells. During auxiliary vaccination, animals were injected with a weakened poxivirus expressing SIV proteins.

Six months after the last vaccination, vaccinated and unvaccinated animals were subjected to 12 weekly episodes of rectal administration of the monkey immunodeficiency virus. At the same time, the overall effectiveness of vaccination was 70%, and the effectiveness for a single episode of infection was 87%. Over the next two years, uninfected animals were subjected to two more series of repeated episodes of infection. During the second series, the effectiveness of vaccination for an individual episode of infection was 82%, and during the third series – 84%.

According to Dr. Robinson, such an infection scheme was chosen in order to reproduce the conditions of sexual infection.

During phases 1 and 2 of clinical trials involving more than 400 uninfected patients, the first-generation vaccine developed by the researchers, which does not express GM-CSF, demonstrated excellent results in terms of its safety, as well as reproducibility of reactions to vaccination.

Based on the results of these studies, permission was obtained for the transition from phase 1 of the primary safety testing of the GM-CSF-expressing 2nd generation vaccine, which is scheduled to begin in March this year, to phase 2b of a clinical trial of the effectiveness of the vaccine with the participation of volunteers who are at high risk of HIV infection. The tested vaccine is designed to form immunity against the strain of the virus most common in South and North America. The license for the production of the vaccine belongs to GeoVax Labs. (It can be assumed – although the press release of Emory University says this very vaguely - that vaccines for humans of both the 1st and 2nd generations express proteins of the human virus, and not monkey immunodeficiency – VM.)

Report by Harriet Robinson et al. Long-term Protection by a GM-CSF Co-expressing DNA/MVA Vaccine in the SIV/Macaque Model was presented on March 7 at the Conference on Retroviruses and Opportunistic Infections (CROI), held in Seattle, Washington.

Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of Emory University:
HIV/AIDS Vaccine Shows Long-Term Protection Against Multiple Exposures in Nonhuman Primates.

14.03.2012