HIV vaccine invention not too far away?

Currently there is no effective HIV vaccine. There have been many attempts to develop HIV vaccine but none of them prove to be successful. All previous attempts used substances aimed at stimulating the body's immune system to produce antibodies or killer cells that would eliminate the virus before or after it infected cells in the body but they all failed. But this new research under the guidance of Philip R. Johnson, M.D., chief scientific officer at The Children's Hospital of Philadelphia showed how invention of effective HIV vaccine may come even sooner than scientists were expecting it.

This time scientists used completely different approach that bypasses the usual path followed by vaccine developers. By using gene transfer technology that produces molecules that block infection, the scientists protected monkeys from infection by a virus closely related to HIV—the simian immunodeficiency virus, or SIV—that causes AIDS in rhesus monkeys. Johnson said how they basically "used a leapfrog strategy, bypassing the natural immune system response that was the target of all previous HIV and SIV vaccine candidates".

Though there is a reason for hope there are still many hurdles ahead before we see HIV vaccine for humans. According to Johnson if by any chance this technique leads to an effective HIV vaccine, such a vaccine may be years away from realization because of further studies that need to be conducted before this technique becomes an actual preventive measure against HIV infection in people.

The research was done in two phases. In the first phase, the research team created antibody-like proteins (called immunoadhesins) that were specifically designed to bind to SIV and block it from infecting cells. Once proven to work against SIV in the laboratory, DNA representing SIV-specific immunoadhesins was engineered into a carrier virus designed to deliver the DNA to monkeys. The researchers chose adeno-associated virus (AAV) as the carrier virus because it is a very effective way to insert DNA into the cells of a monkey or human.

In the second part of the study, the team injected AAV carriers into the muscles of monkeys, where the imported DNA produced immunoadhesins that entered the blood circulation. One month after the injection of the AAV carriers, the immunized monkeys were injected with live, AIDS-causing SIV. The majority of the immunized monkeys were completely protected from SIV infection, and all were protected from AIDS. In contrast, a group of unimmunized monkeys were all infected by SIV, and two-thirds died of AIDS complications. High concentrations of the SIV-specific immunoadhesins remained in the blood for over a year.

Further studies should give us an answer was this a first successful step that could lead scientists to HIV vaccine discovery. Let us hope it is.

Source: http://interesting-science-facts.blogspot.com/