Thursday, March 8, 2012

Vaccine promises long-lasting protection against HIV

Scientists are getting closer to developing a vaccine that protects against HIV infection. Despite years of research, full protection against the devastating virus is still not possible. A study performed in primates shows a new vaccine might succeed where others have failed. Naturally, it remains to be seen whether we can reproduce the same results in humans, but it is a promising development.

At the Emory University in collaboration with GeoVax Labs, studies were performed with primates and SIV, which is the monkey version of HIV. For research, this is often used as a test setup, as it would be rather unethical to do human testing with HIV infection. A vaccine consisting of molecules that mimic HIV/SIV structures and a compound that provokes an immune response were used to test protection against the virus.

Monkeys were given several injections: partly DNA, partly protein and partly inflammatory molecules. Scientists hope this to be the right mixture to acquire adequate protection against SIV. They started off with two DNA injections combined with a pro-inflammatory molecule, used to get the body in shape for what's coming next, which is known as priming. Step two was a series of injections with a modified, safe virus that has HIV proteins built into it. This is what the body actually needs to be trained for: the immune system needs to recognize, and respond to, structures that look like HIV.

Vaccinating the animals in this order resulted in most animals being protected against repeated exposure to SIV, though not all of them remained unscathed. Because the primates were continuously infected over the course of two years, it shows that a vaccine such as the one developed at Emory University can provide long-term protection. This is particularly interesting, because viruses tend to mutate and circumvent the protection given by vaccines.

Next, the vaccine needs to be adapted for use in humans. Part of it has already proven to be safe, which is fortunate. Of course we cannot go around infecting people with HIV to see if it works, but once safety tests are out of the way, a large risk group could receive vaccination, which could then be evaluated at a later time to assess whether any of them has acquired an HIV infection. Because not all the necessary tests have been done yet, it will take some time before a vaccine can be marketed.

Other attempts
HIV infection frequently results in AIDS, which currently is not curable, though there are various drugs available to prolong the life of AIDS patients. Preventing infection is naturally more desirable. Various attempts are being made to get rid of his nasty virus: previously, scientists have already discovered new leads for HIV vaccination. Interestingly, glowing cats and our muscles can aid us in attempts to prevent infection. In addition, a naturally occurring molecule is also of interest to HIV researchers.
HIV entering a cell. It uses specific molecules to let itself be taken up into the cell , after which it uses cellular structures to get its genetic code copied and reproduced. For this, it uses the enzyme reverse transcriptase, making it a retrovirus.

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