Immune-suppressant vaccine blocks HIV infection in monkeys: human trials planned

the medically specific terminology and scientific details were taken in large part from NAM and Aidsmap, an excellent source and knowledge, science and support. 

 

A novel vaccine has been shown to completely block rectal infection of SIV, the monkey equivalent of HIV, in rhesus Macaques. The same vaccine was also shown to produce rapid re-suppression of viral load ( the level of HIV in the blood) in monkeys who were previously infected with SIV. The vaccine program is a collaboration between scientists at the French Institute for Research into Cancer and HIV Vaccines at Paris-Descartes University and ones at the Chinese Tropical Medicine Institute at the University of Chinese Medicine in Guangzhou.

 

 

Following the study’s outstanding success in primates two initial safety trials are now planned in humans. According to aidsmap.com: in one trial, HIV-negative volunteers at low risk of HIV will be given the vaccine to see if it stimulates the same immune- and virus-suppressant responses. In the other trial, HIV-positive volunteers on fully-suppressive antiviral therapy will be given the vaccine and then taken off six months later if test tube results suggest the vaccine has produced such responses.

 

The vaccine consisted of inactivated SIV administered alongside doses of familiar bacteria – in the first case the TB-suppressant bacterium BCG, and subsequently with gut bacteria of the Lactobacillusgenus, including one type commonly used in probiotic supplements. This suggests that if human studies replicate the success seen in monkeys (by no means assured in vaccine studies) the vaccine could be administered in a drink.

 

How does it work:

The researchers designed the vaccine according to  a long-held hypothesis that conventional vaccines ( that rely on stimulating an immune response to a microbe in advance of exposure to it) could not work in preventing the spread of HIV, as this virus uses the very cells that proliferate in an immune response – primarily CD4 T-cells – as the ones it chooses to reproduce in. Therefore with an HIV vaccine the challenge for researchers would therefore be to induce the body to recognize HIV but not to mount a proliferative response to it. This could work if the body is induced to respond to HIV as if it was harmless – to induce so-called ‘immune tolerance’ to it.    

a healthy human T-Cell

a healthy human T-Cell

 

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