A boy receives medication at Nkosi's Haven, south of Johannesburg November 25, 2011. Nkosi's Haven provides residential care for destitute HIV-positive mothers and their children.
A boy receives medication at Nkosi's Haven, south of Johannesburg November 25, 2011. Nkosi's Haven provides residential care for destitute HIV-positive mothers and their children. Reuters

Scientists from the California Institute of Technology have come up with a gene therapy approach that has proven “completely” effective in protecting mice (with humanized immune systems) against HIV infections. These findings were published in journal “Nature” on Wednesday.

The scientists found two antibodies, b12 and VRC01, that protected mice infected with HIV dosages that were 100 times higher than that of a natural infection. The expression of the antibodies stayed high after 52 weeks, suggesting that the treatment is a long-term vaccine-like solution.

So far, traditional vaccines have not worked against HIV as scientists have failed to find a molecule that induces the immune system to produce enough potent antibodies. The difficulties stems from the fact that HIV disguises some of its external structures from the antibodies.

In the gene therapy approach, the Caltech scientists used a genetically altered virus to infect muscles cells and deliver DNA codes of potent antibodies isolated from the blood of human HIV victims. The muscle cells then began to manufacture the antibodies in quantities that proved completely protective against HIV infection.

Despite its effectiveness, this approach remains controversial.

First, success in mice with humanized immune systems does not always translate to success in humans.

Second, because the DNA codes are permanently inserted into the muscle cells, it is difficult or impossible to turn off the production of the antibodies. This would present problems, for example, if there were negative reactions against the antibodies.

Nevertheless, gene therapy – at least the exploration of this approach – may be the best option at the moment.

Traditional vaccines have simply not worked so far. “Nature” noted that while regular (and lifelong) injections of the antibodies could be safer, it is far from cost effective.

The Caltech scientists’ approach, contrastingly, could do the job of protecting against HIV indefinitely with just one injection.

David Baltimore of Caltech, who participated in this breakthrough, aims to conduct trials on humans in the next few years, according to “Nature.”

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