Three to four times more effectiveness compared to conventional influenza vaccines
For almost a decade, the search for an ideal influenza vaccine has been one of the most important research aims in Genomics Research Center (GRC), Academia Sinica, Taiwan.
Researchers at GRC have developed a new vaccine with three to four times more effectiveness compared to conventional vaccines.
Since the first Type A flu vaccine was developed more than 70 years ago by U.S. physician scientists, Thomas Francis Jr. and Jonas Salk, the influenza vaccine has evolved into quadrivalent protections, meaning a vaccination shot gives you the protection against two strains of type A flu and two strains of type B flu.
However, nature will constantly change the gene sequences to create new strains of influenza viruses, rendering the vaccine useless.
With the current method of egg-based vaccines, you never know if by the time the vaccines are out in the market after six months of manufacturing work, the circulating viruses are not already morphed into a different run-away kind. A slight change of the targeting strain can yield a whole new strain within the same sub-type flu, for example H1N1, and the current vaccines have very questionable effectiveness against cross strain viruses.
The researchers have found that the monoglycosylated HA (HAmg) protein vaccine is a cross-strain influenza vaccine which can induce more neutralising antibody to give better protection against a lethal dose of virus infection from strain-specific and cross-strain H1N1 viruses. Lab result also show a three to four times increased protection rates compared to market available vaccines.
HA is a major virus surface glycoprotein that is responsible for grabbing host cells for the influenza virus. The key to the potency of this new vaccine lies in playing with the glycans on the surface of the HA protein. Prior findings showed that in the mushroom like core structure of the HA protein, abundance of glycans are found attaching to its surface. By removing these glycans and only keeping a single mono-sugar, therefore, named as HAmg (monoglycosylated HA), and by a way to split the HAmg virus to remove its infectivity and then inject into the host, the immune response appears to be much more effectively induced. The immune system will no longer be fooled by the glycan camouflage on the surface of virus and thus making antibodies with focus to fight off the intrusions.
The researchers also found that the resulting antibodies can target the stem area of the HA protein, making it a powerful strike. It was also very interesting to have observed an enhancement of the antibody-dependent cellular cytotoxicity (ADCC) against influenza-infected cells.
By leveraging on the conventional egg-based flu vaccine production method, the new vaccine method can offer maximal protection against cross-strain influenza infections. Their development was published in the Proceedings of the National Academy of Sciences of the United States of America (PNAS).
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