Researchers from The Scripps Research Institution (TSRI), Harvard, MIT and other institutions made ground-breaking discoveries that has led to a HIV (Human Immunodeficiency Virus) vaccine that could be tested in humans in as little as 2 years. This vaccine, administered via several injections over weeks to months, works by providing man-made molecules that mimic specific parts of the virus structure to gradually train the immune system to make broadly neutralizing antibodies against HIV.
Challenges
One main challenge of developing a HIV vaccine is to keep up with the virus’ ability to mutate rapidly into new strains. HIV causes victims to become immune-deficient by continuously mutating while the body’s immune system relentlessly attempts to cope. Left untreated, infected people develop AIDS (Acquired Immune Deficiency Syndrome).
In addition, HIV is remarkably different from other viruses by being covered with shielding proteins which act as decoys. The immune system develops antibodies against these decoys instead of attacking vulnerable parts of the HIV.
In contrast, developing the smallpox and polio vaccine was much less tricky. The smallpox vaccine simply contains a live ‘relative’ of the virus, and the polio vaccine contains killed virus or weakened live virus.
How does the new vaccine work
Research pertaining to the development of this new vaccine was published in three articles in high impact journals, two in Science and one in Cell. One of the articles in Science proved that engineered molecules that resembled a vulnerable region of HIV could make the body’s immune system produce early versions of broadly neutralising antibodies. Subsequently, the immune system could produce mature versions of these neutralising antibodies by being successively exposed to substances that mimicked additional aspects of HIV.
The article in Cell demonstrated that the use of an engineered molecule successfully enabled the final stage of the maturation process of these neutralising antibodies. This particular engineered molecule was used in a vaccine for rabbits and showed promising results, as published in Science.
The idea of developing such a vaccine came from the knowledge that in a very small number of people infected with HIV, their immune systems ‘learn’ how to make broadly neutralising antibodies that are protective against HIV. These individuals did not develop AIDS even without medications. Hence, scientists believed that an effective vaccine would be one which induced a subset of antibody-making B-cells that are capable to producing suitable antibodies to proliferate, and allowed successive exposure of these B-cells to antigens for production of broadly neutralising antibodies.
Future goals
Scientists leading the research are Dennis Burton, David Nemazee, and William Schief from TSRI. These researchers and their teams have a long-term goal of designing a vaccine that works in humans and effectively prevents infection despite HIV’s ability to mutate rapidly into new strains.
“It works much better than we expected,” Nemazee said, “The vaccine appears to work well in our mouse model to ‘prime’ the antibody response.” Anthony S. Fauci, director of National Institute of Allergy and Infectious Diseases shared that, “Whenever you get a result that is encouraging, the next step is to see if we can duplicate that in a very gradual, safe, gingerly way in humans in a Phase 1 trial.”
Source: biotechin.asia
