(CN) — Scientists are on the way to developing a vaccine that will deliver lifetime immunity against influenza.
According to a study published Friday in Nature Communications, flu viruses are constantly evolving and thus scientists typically design flu vaccines to induce an antibody response to the virus’ latest version, distinguished by the arrangement of proteins covering the exterior surface.
However, the Oregon Health and Science University (OHSU) team that led the study took a different approach. They worked in collaboration with other research institutions such as the Tulane National Primate Research Center, the University of Pittsburgh, the University of Washington (UW) and the Washington National Primate Research Center at the UW.
The study scientists used a vaccine platform that OHSU scientists previously developed to fight HIV and tuberculosis. It involves inserting small pieces of target pathogens into the common herpes virus cytomegalovirus (CMV), which infects most people in their lifetimes and usually produces mild to no symptoms. This method caused the virus to become a vector that induces an immune response from the body’s T cells, which senior author Jonah Sacha said would fight influenza more effectively.
“The problem with influenza is that it’s not just one virus,” said Sacha, a professor and chief of the division of pathobiology at OHSU’s Oregon National Primate Research Center. “Like the SARS-CoV-2 virus, it’s always evolving the next variant and we’re always left to chase where the virus was, not where it’s going to be.”
To better combat the evolutionary nature of the virus, the scientists had a theory that their vaccine could focus on a specific type of T cell in the lungs called effector memory T cell, which targets the internal structural proteins and the virus. The scientists said a vaccine designed that way would have the T cells seek and destroy any cells infected by an old or newly evolved influenza virus.
To that end, the scientists designed a CMV-based vaccine using a template of the 1918 influenza virus that killed millions of people around the world. Then, the scientists said that they inoculated 11 non-human primates before exposing them to small particle aerosols containing the severe avian H5N1 influenza virus — currently circulating in dairy cows in the United States — in a highly secure biosafety level 3 laboratory at the University of Pittsburgh.
Despite a century of evolution, the virus failed to kill six of the 11 primates thanks to the vaccine.
“It worked because the interior protein of the virus was so well preserved,” said Sacha. “So much so, that even after almost 100 years of evolution, the virus can’t change those critically important parts of itself.”
Encouraged by their findings and what it could mean for future vaccine development, the scientists suggest that by synthesizing more up-to-date virus templates, CMV vaccines may generate an effective, long-lasting immune response against a wide range of new variants.
“It’s exciting because in most cases, this kind of basic science research advances the science very gradually; in 20 years, it might become something,” said Sacha. “This could actually become a vaccine in five years or less.”