Wed, Jun 17, 2009 page4

• Researchers tout vaccine breakthrough

  BREAKING THE SHELL Researchers from Academia Sinica discovered a way to remove the glycan shield that prevents the body from attacking and then extinguishing viruses

  • By Meggie Lu / STAFF REPORTER
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  Academia Sinica yesterday touted a breakthrough in cancer and universal flu molecular vaccine development.

  Speaking at the 12th Society of Chinese Bioscientists in America (SCBA) International Symposium, Academia Sinica President Wong Chi-huey (翁啟惠), who is also the research project’s leader, said that traditional vaccines are manufactured by inactivating whole viruses and injecting them into human bodies.

  “Molecular vaccines, on the other hand, are made with only the most important or abundant ­molecules of the virus,” he said.

  This is because when a virus enters the body, the body’s immune system is mainly triggered by the most important or abundant molecules, while the rest of the virus does not really cause a reaction, assistant researcher Ma Che (馬徹) said.

  “In the case of the flu virus, the part that matters is the hemagglutinin [HA] molecule — which is the ‘H’ in ‘H1N1,’” he said.

  The ratio of HA molecules and neuraminidase (NA, or the “N” in H1N1) molecules on the H1N1 virus surface is about 10 to 1, he said.

  However, the HA usually shields itself with glycan — or sugars — so the body doesn’t recognize it as an HA molecule, Ma said.

  “As many molecules in the body are covered with glycan, when the HA is also covered by glycan, the body does not attack it,” he said.

  In Wong and Ma’s study, the team was the first in the world to take the glycans off the HA molecule, exposing the protein sequence underneath.

  “We found that the [bare] protein was a much better antigen [one that attracts attack from the human immune system] and induces a much better response. As such, we are using glycan-free HA molecules as the vaccine, instead of using the whole flu virus structure,” Ma said.

  The advantages of such ­molecular vaccines are multiple.

  “First, it simplifies things — we only focus on the most important molecule that matters in the flu virus, the HA,” Ma said.

  In addition, after having the surface glycan ripped off, the regions where H1 and H5 [the avian flu virus] viruses are similar are exposed, Ma said.

  “We already knew that H1 and H5 viruses have regions that have similar protein sequences, but because these regions used to be covered by glycan, we had to use different vaccines for the two viruses; with the similar regions now exposed, a vaccine for an H1-type flu can potentially also protect people from an H5-type flu,” he said.

  “For the flu vaccines, I estimate that they can be ready for sale within three to 10 years,” Wong said. “This is definitely a giant step in terms of progress in vaccine development.”

  Wong also unveiled a research project that would lead to the development of molecular vaccines for five types of cancer: including breast, prostate, ovarian, lung and colon cancer.

  “We discovered that on the cancer cells of these five types of cancers, a unique glycolprotein which doesn’t exist elsewhere in the body, called ‘Globo H,’ is found,” Wong said.

  When cancer-free people are injected with a molecular vaccine that uses Globo H as the basis, “their bodies will recognize Globo H as a cancerous molecule when they develop cancer one day and extinguish it,” he said.

  The molecular vaccine is ­potentially effective even when the injection takes place in childhood, Wong said.

  In related news, the Central Epidemic Command Center (CECC) yesterday announced four more confirmed A (H1N1) influenza cases, bringing the nation’s total to 55 cases, 28 of which came from Thailand and 20 of which cam from the US.

  Two of the new cases came from Thailand. Both were office workers in their 20s.

  The third case was a 57-year-old retired woman who visited the US between May 28 and June 10, while the fourth one was a 16-year-old male student returning from the US for summer vacation.

  ADDITIONAL REPORTING BY JIMMY CHUANG
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