April 16, 2001 -- Scientists at the Los Alamos National Laboratory in New Mexico report that they have designed decoy molecules that, in laboratory studies, can stop the spread of Staphylococcal superantigen, a toxin responsible for about 25 percent of the food poisoning cases in the United States. The same method might be used to fight similar toxins, including those associated with anthrax, HIV and toxic shock syndrome, according to the researchers.
The research is reported in the current (April 10) issue of Biochemistry, a peer-reviewed journal of the American Chemical Society, the world's largest scientific society.
The decoy molecules are better suited to protect the body's immune system from attack than currently used antibiotic approaches, according to Goutam Gupta, Ph.D., who led the research project. Ideally, the decoys could offer a faster-acting, more effective alternative to stop the toxins, he said. If all goes well with further research, he believes it could be given to patients suffering from food poisoning or toxic shock syndrome, or given prior to possible exposure to biowarfare agents like anthrax.
Staphylococcus, or staph toxin, is a protein with two binding sites on its surface that it uses to spread from cell to cell in the body. Staph toxins are bacterial "superantigens" that overstimulate the body's immune system, turning it against itself.
The decoy molecules target the binding sites and prevent the toxin from attaching to cells, Gupta said. The toxins eventually die if they are unable to infect any other cells. The decoys are not expected to upset the functions of normal cells in the body, Gupta noted.
In the laboratory study, the decoy molecules successfully disarmed a model staph toxin, Gupta said. Toxins implicated in several other diseases and infections, including anthrax, HIV and toxic shock syndrome, act in much the same way as the staph toxin, according to Gupta.
He feels that the similarities between staph toxin, anthrax toxin and an HIV protein called gp120 indicate that the same decoy technique could be used to block the spread of them all. A decoy modified to fight HIV, for example, would battle the gp120 protein that allows the virus' expansion, but should not be considered a cure to the disease, Gupta said.
The next step for the research team is to perfect a system to deliver the molecule to the right places, according to the researchers.
"I am very optimistic about our chances," Gupta said. "We know the mode of action of these toxins and I believe we can find countermeasures to stop them. We have proven the principle of our approach works, but we still want to find a better way to bind them and block their activities."
The research was funded by grants from the U.S. Department of Energy and the Defense Advanced Research Project Agency, part of the U.S. Department of Defense.
Goutam Gupta, Ph.D., is a researcher in the bioscience division of the Los Alamos National Laboratory in Los Alamos, N.M.
The above story is based on materials provided by American Chemical Society. Note: Materials may be edited for content and length.
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