Recently, a promising HIV experimental vaccine failed to prevent experiment participants from infection. And it’s reported that gut microbiome interfere with the effect of the vaccine. Another important finding for the reasons of failure is that protein-binding antibodies were found in the blood that had not been injected with the experimental vaccine.
The vaccine is HVTN 505, the most promising one in recent years, but the development process stopped in 2013 for that, it was found failed to protect experiment participant from infecting with HIV in the trial period.
Good news is that scientists have found the main reason, which will give direction to the new successful HIV vaccine R&D.
It’s the first time that scientists found microbiome played an interfering role in the process when a vaccine took effect. At present scientists propose a hypothesis that microbiome is the origin of the failure, and the hypothesis will lead new studies on the influence of microbiome on immune system.
By tracking the reason of why the vaccine failed to work, scientists found after the injection of the vaccine, a type of antibody will be produced. The antibody is also produce at very young age after the child is given to birth, but there won’t be such antibody made when the human body goes into maturity in adulthood.
Scientists also found the antibody on people that were naturally infected with HIV virus. And when they test the people who received the experimental vaccine, they found similar situation. The vaccine would boost the production of antibodies that bound with HIV protein and other bacteria. Antibodies protein binding with virus and microbiome in the blood of participant before the vaccine injection were also found, which showed that the vaccine driven antibodies were produced by B cells in bodies.
And now scientists think that the HIV protein mimic helpful gut bacteria by binding with other bacteria, and then escape from the attack of immune system. But all is in the stage of brave guess, more researches are needed to find out the real reason of the failure, and lay a better foundation for the R&D of new HIV vaccine.