A potential universal vaccine to fight against infection caused by various influenza viruses, including the highly pathogenic avian H5 virus and the pandemic H1N1 virus, has been identified by scientists.
The scientists from the International Vaccine Institute (IVI) have discovered that an antigen common to most influenza viruses and commonly referred to as matrix protein 2 (M2), when administered under the tongue could protect mice against experimental infection caused by various influenza viruses.
Importantly, this experimental sublingual vaccine was found to induce immunity in the lungs whereas the same vaccine administered by injection failed to do so and conferred only limited protection against experimental infection.
The influenza virus M2 has already been considered as a rational target antigen for development of a universal flu vaccine because this protein is highly conserved among the different types of influenza viruses. However, attempts to develop M2-based vaccines administered by injection have been unsuccessful.
"Sublingual vaccination with M2 induced immune responses in the lungs of mice whereas the same vaccine administered by injection failed to do so," said Dr. Man-ki Song, IVI scientist and lead author of the study.
"This is probably why earlier attempts involving injection of M2-based vaccines failed to protect against influenza infection and disease.
"This vaccination approach offers an additional strategy to prevent influenza infection and may be used to control potential influenza pandemics," Song added.
Plans to test this vaccination approach in humans are being considered.
The study was reported in the November 30th issue of the journal PLoS ONE.