Nasal Spray Blocks Infuenza in Mice

Scientists at Ohio State University have created an antibody that was successful in protecting a majority of the tested mice from lethal influenza (flu) doses, even preventing some from experiencing any symptoms at all. According to the study’s co-lead author Kai Xu, PhD, the engineered molecule — transmitted via nasal spray — works by triggering “mucosal immunity,” meaning it coats the tissue that lines the body’s organs and tracts before a virus can enter. By contrast, current flu vaccines rely on “systemic immunity,” which fights the virus after infection. Dr. Xu said combining both immune responses into one engineered antibody could “enhance the protection” of conventional, injection-based vaccines.

When tested on mice using a nasal spray, the antibody successfully stuck to their mucosal surfaces for a week, protecting most from lethal doses of common flu strains. Dr. Xu said this finding suggests the antibody could work similarly in humans.

Researchers created the new antibody by combining two existing ones: immunoglobulin G, which makes up most antibodies in the human body and has two “arms” to target specific viruses, and immunoglobulin M, the immune system’s first line of defense with 10 “arms” to attack infection. Traditionally, flu prevention has focused on IgG, but the flu virus can mutate, making it harder for IgG to identify and fight it. IgM, on the other hand, can still latch onto the virus even if a part of it changes because its many arms. By combining IgM’s “stickiness” with IgG’s precision, Dr. Xu said the new antibody could neutralize the flu more effectively than either antibody alone.

If used to complement existing flu vaccines, the engineered antibody would be especially beneficial not only in years when medical professionals inaccurately predict the specific strain that spreads during flu season, but also for individuals who don’t have a strong immune response to vaccines. “Our creation can complement the conventional vaccine in terms of targeting to prevent the seasonal flu infection,” said Dr. Xu, who is also an Ohio State assistant professor of veterinary biosciences. “It can be a replacement, but we believe that these two can synergize with each other.”