For the research, as reported in European Pharmaceutical Review, scientists revealed that vaccinating mice against influenza viruses using double-layered protein nanoparticles was successful. The target the stalk of the protein was found to produce long-lasting immunity.
Tests showed that the mice were fully protected against various types of influenza A viruses. Commenting on the research outcome, lead researcher Professor Bao-Zhong Wang, from Georgia State University, said: “Vaccination is the most effective way to prevent deaths from influenza virus, but the virus changes very fast and you have to receive a new vaccination each year.”
The scientist added: “We’re trying to develop a new vaccine approach that eliminates the need for vaccination every year. We’re developing a universal influenza vaccine. You wouldn’t need to change the vaccine type every year because it’s universal and can protect against any influenza virus.”
The aim of the vaccine was to induce responses to the protein stalk part of the influenza surface glycoprotein, instead of the typical target of the head. Glycoproteins are proteins that contain oligosaccharide chains covalently attached to polypeptide side-chains, formed from a process called glycosylation.
While the stalk domain offered protection, it is not, in itself stable. The researchers needed to devise a way to make it stable. This was performed by assembling a stalk domain into a protein nanoparticle as a vaccine. The nanoparticles were unique to the research since the particles were generated to contain only the protein that was capable of inducing immune responses.
To show the effectiveness of the nanoparticle vaccine, the science team immunized mice on two occasions via an intramuscular shot. The rodents were then exposed to several influenza viruses (H1N1, H3N2, H5N1 and H7N9). Careful study of the mice indicated that the immunization provided universal protection.
The next step on the path to a vaccine to be used on humans is for the researchers to test out the nanoparticle vaccine in ferrets. Ferrets are similar to humans in relation to the orchestration of their respiratory system.
The research has been published in the journal Nature Communications, with the study headed “Double-layered protein nanoparticles induce broad protection against divergent influenza A viruses.”