Coral Yields Medically Useful Compounds
In the waters off the coast of northern Australia lives a species of feathery coral. Years ago, bits of it were collected by the Australian Institute of Marine Science and stored at the National Cancer Institute's extract repository, along with 200,000 other samples. When researchers retrieved and tested it, they found that it was very effective at blocking HIV infection of host cells.
Their findings were presented by Koreen Ramessar of the National Cancer Institute at a conference on April 29, with a full report slated for release in the near future. Even though the results are preliminary, they raise hope that the coral extracts could be used to boost the efficacy of preventative treatments.
According to estimates by the World Health Organization, 35.3 million people were infected with HIV at the end of 2012, with approximately 2.3 million new cases that same year. If untreated, HIV will progress to its disease-form, AIDS, once the virus reduces a person's immune system T-cells to below a certain threshold (200 cells per cubic millimeter). While antiviral treatments have advanced in the past decade, more than a million people still die from AIDS-related conditions every year.
The researchers isolated a specific protein from the coral sample that stops an HIV virus from entering T-cells — a critical step in viral reproduction and, thus, progression of disease. This protein, called "cnidarin," is unique to a type of soft coral, although scientists do not yet know what role it plays in coral biology. The researchers believe its anti-HIV ability is due to a characteristic that may be unique to cnidarin.
"We found that cnidarins bind to the virus and prevent it from fusing with the T-cell membrane," said Ramessar. "This is completely different from what we've seen with other proteins, so we think the cnidarin proteins have a unique mechanism of action."
There does exist the possibility that the virus would become resistant to cnidarin if it is used in preventative measures. However, because it uses a very different mechanism to fight infection than do other anti-HIV medications, it wouldn’t interfere with most current therapies.
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Coral image via Shutterstock.