First human trials of a new HIV vaccine have been conducted by Scripps Research and are showing great promise. the vaccine was able to stimulate rare cells in the immune system that are able to stop the virus in 97% of the participants.
HIV is mutating fast and has been successful in avoiding the effects of vaccines in previous attempts to eliminate it with the vaccine approach. The problem is that the virus attacks the immune system directly and it has the possibility of avoiding its defense mechanisms.
The vaccine was developed by Scripps Research in San Diego and it is currently in phase one of the clinical trials. The research team has tested the vaccine in 48 people in the first phase. This trial and first results evoked excitement in the eye of the public and even more, interest arose after the announcement that Scripps is partnering with Moderna to develop the mRNA version of the HIV vaccine. Researchers believe this could bring the vaccine to the broad public faster and make it more accessible.
The scientists working on this study aim to design vaccines to target rare immune cells with particular features and to stimulate them specifically to achieve the desired effect. They also highlight that their approach will be essential not only in HIV vaccine development but for future research when it comes to making vaccines for other viruses.
HIV vaccine development
Research regarding the HIV vaccine started shortly after the discovery of the virus responsible for AIDS in the 1980s. Unfortunately, the research has not shown much success and the results have not been promising. A previous study published in 2009 used a two-vaccine combination and the results showed a reduction in infection by 31%, which is not enough to submit for approval. However, the scientist continued to learn about what works and what does not to create a more efficient combination. When a follow-up study was conducted, it was concluded that protecting effects weakened after one year.
The biggest challenge in HIV vaccine development is that the virus is skilled in avoiding the immune response of the body. The organism produces antibodies that are designed to locate any foreign intruders and to neutralize them. Since HIV mutates very fast, it has a greater advantage at evading the antibodies. That is why scientists have yet to create a vaccine that is going to be effective enough to eliminate HIV.
The new research shifted focus to a rare set of antibodies, called “broadly neutralizing antibodies”. Their purpose is to connect to so-called spike proteins of the virus, which is a part of HIV that varies very little among various strains. This protein is the main element that allows the virus to penetrate cells.
The problem with the new approach is that broadly neutralizing antibodies are quite rare. They make up about 1 in 1 million of the B cells, the cells of the immune system that produce antibodies.
The Scripps research included 48 healthy individuals. Some of them got the vaccine and the rest got a placebo injection. Researchers then examined whether the vaccine they developed is safe rather than does it prevent HIV. They were interested in whether or not individuals who were given the vaccine developed more effective antibodies than the group who was given the placebo. The results of the study suggested that 97% of participants that got the vaccine developed the desired antibodies.
The question about a new HIV vaccine is still open and follow-up studies need to be conducted to test the safety and effectiveness in larger groups. There is hope, researchers highlight, in a new partnership with Moderna and the mRNA technology that showed success in COVID-19 vaccines.