DNA-based strategy protects against multiple flu strains in study

July 6 (UPI) -- Researchers at The Wistar Institute have created a new synthetic, DNA-based strategy that provides protection against several different influenza viruses.

Influenza vaccines work by triggering the body's immune system to produce antibodies that target the exact types of flu virus in each year's seasonal flu vaccine.

Scientists from The Wistar Institute collaborated with MedImmune and Inovio Pharmaceuticals, Inc., to develop a method involving DNA sequences that encode protective antibodies into a vaccine. The antibodies protect against certain strains of the flu but do not provide protection from all flu virus strains.

"We devised a different method from the traditional vaccine strategy, and instead of relying on the immune system to respond to a vaccine, this new strategy delivers DNA sequences that directly encode the protective antibodies rather than inciting the production of antibodies through an immune response," Sarah T.C. Elliott, a postdoctoral fellow in Wistar's Vaccine and Immune Therapy Center in the Weiner lab, said in a press release. "This new synthetic DNA-based strategy -- termed DMAb's -- delivers monoclonal antibodies that provide protection against highly diverse strains of influenza."

Traditionally, seasonal flu vaccines are only effective against strains identified each spring in sentinel laboratories and vaccines must then be rushed into production to have enough available when flu season starts.

"The matching process is not a perfect science, therefore, in some flu seasons, the vaccine available in the fall is not a good match for the circulating virus strains and is less effective," David Weiner, executive vice president and director of the Vaccine and Immune Therapy Center at The Wistar Institute, said.

"Flu occasionally can also shift strains dramatically resulting in a pandemic strain that requires a new strategy for developing the vaccine, leaving the U.S. population at risk of major health consequences. Furthermore, some vulnerable populations may not respond well to vaccines, and new approaches that are simple, rapid and can broadly protect against influenza would be a major step forward."

Researchers tested their method by studying the DNA sequences for two human monoclonal antibodies -- one that broadly targets the influenza A virus and one that targets influenza B viruses.

Results from mouse models showed that the delivery of the DMAb sequence for influenza A targeted monoclonal antibody protected against lethal doses of two different influenza A viruses. The same results were shown for influenza B viruses.

The study was published July 6 in NPJ Vaccines.