The International AIDS Vaccine Initiative (IAVI) and Scripps Research recently announced the results of a major Phase I clinical trial. The researchers tested a new vaccine approach designed to prevent HIV infections by stimulating the production of rare immune cells. These cells are needed to create the right antibodies to fight HIV.
The trial saw 48 participants divided into a low-dose group or a high-dose group. They received the candidate vaccine or a placebo in two doses two months apart. Of those who received the vaccine, 97 percent developed the right immune cells to respond to an HIV infection.
“This study demonstrates proof of principle for a new HIV vaccine concept, a concept that could be applied to other pathogens as well,” Dr. William Schief, professor and immunologist at Scripps Research and executive director of vaccine design at IAVI’s Neutralizing Antibody Center (NAC), whose laboratory developed the vaccine, said in a statement. “With our many collaborators on the study team, we have shown that vaccines can be designed to stimulate rare immune cells with specific properties, and that targeted stimulation can be very effective in humans. We believe that this approach will be the key to making an HIV vaccine and possibly important to making vaccines against other pathogens. “
The results were presented at the International AIDS Society HIV Research for Prevention (HIVR4P) virtual conference in February. The team has sought to stimulate the body to create broadly neutralizing antibodies or bnABs, specialized blood proteins that can stick to the tips on the surface of HIV. This is an immune response that can neutralize several strains of the virus.
“We and others have postulated for many years that, to induce bnAbs, you must start the process by activating the right B cells – cells that have special properties that give them the potential to grow into bnAb-secreting cells,” explained Schief. “In this test, the target cells were just one in a million of all virgin B cells. To get the right antibody response, we first need to prepare the right B cells. The data in this trial affirm the vaccine’s immunogen’s ability to do this. “
This priming approach would be the first step in a series that would allow an individual to develop immunity against the disease. And the team believes that priming can be used as a starting point in vaccines that fight different strains of influenza, in addition to dengue, zika, hepatitis C virus and even malaria.
The clinical trial, known as IAVI G001, is a fantastic result. Researchers are partnering with the modern biotechnology company (famous for the COVID-19 vaccine) to develop and test a mRNA-based vaccine that produces this immune response.