Instant Immunity Drugs Against Cancer, Hiv Pique Pfizer
While “instant immunity” vaccines will take years to develop for use in people, they may be tested against AIDS in monkeys by the end of the year, said Carlos Barbas, a Scripps Research Institute scientist who led a study that will appear in this weeks Proceedings of the National Academy of Sciences.
The new technique gives more firepower to the bodys natural defenders and has shown the ability to fight two types of tumors in mice, said Barbas. Pfizer Inc., the worlds biggest drugmaker, has bought the rights to the technology, he said.
“This approach allows you to make antibodies against almost anything,” Barbas said Feb. 26 in a telephone interview. “It could be the weak spots on the surface of HIV or molecules on the surface of a tumor cell.”
Most vaccines contain pieces of viruses or germs that prepare the immune system to start making proteins called antibodies when a real infection occurs. That process of immunization can take weeks to months, a key reason that most vaccines cant be used to treat infectious diseases.
Instant Attack
Antibodies are Y-shaped immune molecules that disable foreign cells, viruses and proteins by latching on to them. Barbas and his team found a way to instantly outfit antibodies to attack virtually any molecule of choice.
Barbas stimulated mice to make antibodies that bind with an all-purpose “linker” molecule. Like the various heads of a socket wrench, the linker molecule can be designed to grab viruses, cells and proteins of all shapes and sizes.
Once the immune system has learned to make a specific antibody, it can usually produce it each time the foreign substance appears. In Barbass system, each time he injected mice with the linker molecules, they made antibodies that picked the linkers out of the bloodstream and then began seeking specific cancer cells they were designed to attack and disable.
In most infections, the AIDS virus confuses the human immune system by offering a variety of targets, most of which arent vulnerable to attack by antibodies. While that has frustrated vaccine efforts to date, the “instant immunity” approach may allow scientists to design an attack that will hit the virus hardest, Barbas said.
Stopping HIV
Scientists have been trying without success to find a preventive AIDS vaccine since the virus that causes it, human immunodeficiency virus or HIV, was discovered in 1981. The instant vaccine approach might be useful as a way to prevent infections in people who are known to have a high risk of exposure to the virus, said Dennis Burton, an immunologist at the Scripps Research Institute who has collaborated with Barbas on other projects.
The instant antibodies may also be useful when new diseases emerge, such as SARS or bird flu, that dont leave time for widespread immunization, Barbas said.
“It could be malaria, it could be anything,” Barbas said. “You would always have universal antibodies waiting to act.”
Should the drug prove promising in animals, it would still take years to test in people, Barbas said.
The technology is still in its early stages, and its too early to say whether “instant vaccines” will become a reality, said Elizabeth Power, a spokeswoman for New York-based Pfizer.
“Pfizer will monitor the progress of this new technology, especially if there could be therapeutic value in this technique for innovative vaccines,” Power said today in an e-mail.