A UNIVERSAL vaccine combating the influenza A virus has been developed by a team of scientists at Georgia State University, Atlanta, Georgia, USA, and is reported to have produced long-lasting immunity in mice. According to the Centers for Disease Control and Prevention (CDC), influenza is one of the leading causes of death in the USA, having resulted in an annual number of deaths between 12,000 and 56,000 since 2010.
Every year a new influenza vaccine is needed to combat the strain of influenza that is predicted to be most prevalent in the upcoming flu season. However, prediction does not always prove accurate, and the 2009 H1N1 pandemic, which resulted in 200,000 deaths in the first 12 months, is a prime example of this. The aim of the universal vaccine is to provide protection against various virus stains and overcome the limitations of seasonal flu vaccines.
The study involved a new approach to influenza vaccine development, where the stalk of the haemagglutinin protein, which is conserved across all influenza strains, was targeted, rather than the highly variable haemagglutinin head, offering the opportunity for more ubiquitous protection. The researchers reported that by assembling the stalk domain into a double-layered protein nanoparticle, long-lasting protection against a variety of influenza strains was observed in mice. Although the haemagglutinin stalk domain offers an ideal target for a universal vaccination, it is not a stable protein. Using the protein nanoparticle around the stalk overcomes this instability, protecting the antigenic protein against degradation and inducing much greater immune cell responses. “We’re trying to develop a new vaccine approach that eliminates the need for vaccination each year”, stated Dr Bao-Zhong Wang, Institute of Biomedical Sciences, Georgia State University.
To determine the effectiveness of the nanoparticle vaccine, the researchers administered the injection twice intramuscularly to mice. The mice were then exposed to the H1N1, H3N2, H5N1, and H7N9 influenza virus strains and universal protection against all these strains was observed, as well as a reduced viral load in the mice lungs. The researchers concluded that, despite the positive results, further tests of the nanoparticle vaccine in ferrets are required before the new therapy can be trialled for human use.