Researchers at St. Jude's Children's Research Hospital have developed a new approach for creating an influenza vaccine that could guard against multiple flu strains, including pandemic ones.
Current flu vaccines work by generating highly specific antibodies that target and bind tightly to strain-specific regions of hemagglutinin (HA) and neuraminidase (NA) proteins on the virus. Because HA and NA proteins constantly change and evolve, this approach requires developing a new flu vaccine every year.
"While current vaccines provide protection against [seasonal] strains, it is difficult to predict which strains will be circulating each year, and a universal vaccine would solve this problem," wrote study co-author Maureen McGargill, an assistant member of the St. Jude Department of Immunology, to FierceBiotechResearch in an email.
To create their investigational vaccine, St. Jude investigators used the drug rapamycin, an immunosuppressant, to shift the immune response after flu vaccination to stimulate production of antibodies that broadly target flu viruses. When tested in mice against a mild form of the flu--the H3N2 influenza A flu strain--the new strategy created a more diverse antibody response to the vaccination and protected mice against that flu strain as well as the more dangerous pandemic strains, H5N1 and H7N9, when the mice were exposed to them weeks later.
The findings were published in the online edition of the scientific journal Nature Immunology.
"Previous attempts have focused on increasing the generation of antibodies that bind to the conserved portions of influenza by enhancing the immune response, whereas our work shows that protective antibodies against multiple strains are more prevalent when the immune response is decreased," McGargill said.
So far, efforts to create a universal flu vaccine have been unsuccessful, but there are currently many of these potential vaccines in development.
The St. Jude research highlights a potential new approach to generate protective antibodies that recognize and target proteins common among most influenza A strains rather than those unique to each strain. The researchers believe the same vaccine strategy could be applied to vaccine design against other diseases, too.
- here's the press release
- and the study abstract