Important note: Information in this article was accurate in 1997. The state of the art may have changed since the publication date.
The Associated Press; 50 Rockefeller Plaza, New York, NY 10020 - Monday, November 24, 1997; 5:07 p.m. EST
Paul Recer, AP Science Writer
Scientists at the Whitehead Institute for Biomedical Research said that by fusing a molecule from a tumor or a virus with a natural compound called heat shock protein they can create a vaccine that prompts a strong defense against infection or cancer.
Dr. Richard A. Young, lead author of a study to be published Tuesday in the Proceedings of the National Academy of Sciences, said linking the heat shock protein with a particle from a tumor or virus prompts the body to make killer immune cells, called cytotoxic T-cells or CTLs, that are primed to attack a specific target.
Most other vaccines, said Young, cause the body to make antibodies that attack the target but do not prompt production of CTLs, one of the body's most potent weapons against infection and tumor growth.
In a study published in Proceedings, the Whitehead researchers made a cancer vaccine by fusing the heat shock protein with ovalbumin, a protein that is made by some types of cancers.
When the protein combination was injected into laboratory mice, it caused them to develop an immunity against a cancer that is usually lethal to the mice.
"This is a proof-of-concept experiment that shows that the heat shock protein can be attached to most any protein of interest and be useful generally in vaccine development," said Young.
The researcher said his lab is now making a vaccine against simian immunodeficiency virus, or SIV, which is the monkey equivalent of HIV, the virus that causes AIDS. He said the SIV vaccine will be tested for about two years in macque monkeys. If the new vaccine design works against SIV, said Young, then it could be used to make an HIV vaccine for testing in humans.
But the usefulness of the heat-shock protein vaccine goes beyond AIDS, said Young.
He said researchers are trying to identify antigens that are produced by specific cancers. These antigens could then be fused with the heat shock protein to make a vaccine that would prompt the body to attack and kill cancer cells, said Young.
Heat shock proteins are released by the body naturally under conditions of stress, such as heat, injury or damage from toxins. The proteins move around inside cells to help correct any damage done by stress.
The heat shock proteins also play a role in helping the body kill off infected or abnormal cells. They do this by putting on a cell's outer wall a marker molecule that acts as a target for the killer T-cells. The immune system also remembers this target and will mount a new attack if the target is detected again.
When fused with particles from a virus or a cancer, the heat shock protein causes similar tumor cells or virus-infected cells to be targeted by the killer T-cells, said Young.
Copyright 1997/The Associated Press. Reproduced with permission. Reproduction of this article (other than one copy for personal reference) must be cleared through the Permissions Desk, The Associated Press, 50 Rockefeller Plaza, New York, NY 10020.
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