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Two More Potential HIV Vaccines

Despite long-term researchers' efforts, efficient human immunodeficienct virus (HIV) vaccine has not been created yet. However, researchers are not giving up their attempts. Russian biologists are now proposing two more vaccine options based on DNA that encodes human immunodeficienct virus proteins.

Experience proves that traditional ways of creating vaccines based on obtaining medications of killed or live impaired microorganisms do not always ensure to the required result and are not always safe. Therefore, the vaccines that claim to protect mankind from AIDS are developed with the help of contemporary methods of molecular biology: based on individual viral proteins, artificial peptides and genetically engineered DNA. A group of researchers from the Novosibirsk Institute of Bio-Organic Chemistry (Northern Branch, Russian Academy of Sciences) and the Research Institute of Molecular Biology (VEKTOR State Research Center for Virology and Biotechnology) has designed two candidate vaccines based on DNA that encodes viral proteins, which cause immune response.
DNA-vaccines contain genes of definite proteins. Having received the vaccine, the immunized organism is to synthesize these proteins for a long time and to produce immune response to them. This is a more efficient way than to introduce finished protein-antigens. Specialists of the VEKTOR State Research Center for Virology and Biotechnology in Novosibirsk have designed the anti-HIV immunogen protein gene called TBI (T- and B-Cellular Immunogen). This artificial protein has no natural analogue. It combines in a single "body" specific fragments of various viral proteins, each of them causing the laboratory animals' anti-HIV-1 immune response. To intensify immune response, the researchers added the gene of superficial protein of hepatite B (HBsAg) to the synthesized TBI gene, thus, the researchers obtained, in their opinion, a quite innocuous virus-like particle "incrusted" with HIV proteins. Such construction interacts more actively with immune cells than individual proteins do. The second DNA-vaccine, which is designed similarly, contains a fragment of Gag gene - the major protein of HIV membrane.
Immunogenic properties of created vaccines were tested on mice. The mice were intramuscularly injected aqueous solutions of DNA-vaccines, and then, 2, 3, 4, 5 and 6 weeks later their immunity values were assessed. To this end, the researchers drew the mice's blood in minor amounts, by half a milliliter. It has turned out that the mice's blood serum contains HIV-specific antibodies, their number increasing as time passes and reaching the highest value in the fifth to sixth week after immunization.
Therefore, both DNA-vaccines upon a single intramuscular injection cause mice's anti-HIV immune response. In the researchers' opinion, these constructions can be used in the future for prophylaxis of people's HIV infecting. The researchers are panning to continue the investigation.

Informnauka (Informscience) Agency. May 2004.