Scientists are currently working on a "universal" nasal spray, effective against 60 strains of the seasonal influenza virus.
And if to be immune to the seasonal flu, the nasal spray replaced the subcutaneous vaccine? This is the amazing project on which an international team of researchers works, and whose first encouraging works have just been published in the journal Science.
While in France, the vaccination campaign against seasonal flu began in October in pharmacies and medical practices, this new study shows what looks like the vaccine of tomorrow: a nasal spray whose effectiveness will last the entire influenza season, and even the virus mutates rapidly.
Indeed, unlike the subcutaneous vaccine, this spray would be effective against sixty strains of the flu virus. "We still do not have a vaccine that protects against the two main types of influenza (A and B.) The key to this study is the development of a multi-domain antibody that neutralizes the influenza A and B viruses. "says Ian Wilson, professor of structural biology at the Hansen Chair of the Scripps Research Institute.
Lamas antibodies to test its effectiveness
To create a vaccine that can protect against different strains of the flu, the researchers worked from antibodies from llamas. These animals have the particularity of producing single antibodies, smaller and simpler than those of humans, and which therefore fit into smaller binding sites and more indented on the viral surface.
"Here, llama antibodies can easily bind together to create multi-specific antibodies binding to different sites on different targets," explains Professor Ian Wilson. "This multi-specificity is the key to having a wide coverage of highly variable pathogens like the flu." The researchers started by combining two anti-influenza A llamain antibodies and two anti-influenza B antibodies to create a "multi-domain" antibody, able to target influenza A and B viruses, and thus protect against all circulating virus strains that can affect humans and create an epidemic.
Four specific antibodies
"The next question was how to deliver these antibodies," Pr Wilson says. With his team, he then designed a gene expressing a protein of these four specific antibodies, which was integrated with a harmless virus (an adeno-associated virus, or AAV).
This viral vector was then administered into the nostrils of mice via a nasal spray. The goal was to get them to produce these protective antibodies in the upper respiratory tract, the tissues most vulnerable to influenza. After analysis, it was found that the treated mice survived the influenza virus much better than those who did not receive the vaccine. Before a possible commercialization of the spray, it requires additional studies to determine if it will be effective against seasonal flu in humans.