La Jolla, CA. April 16, 2002 — Human antibodies against Bacillus spores, of which one species is the cause of anthrax, have been identified by researchers at The Scripps Research Institute (TSRI). These antibodies could be used to detect the presence of anthrax and other harmful spores in powders and to protect those exposed against lethal infections.
In the current issue of the journal Proceedings of the National Academy of Sciences, scientists Bin Zhou, Peter Wirsching, and Kim D. Janda of the Department of Chemistry and The Skaggs Institute for Chemical Biology describe the antibodies.
"The antibodies," says Janda, who holds the Ely R. Callaway, Jr. Chair in Chemistry, "give you the ability to dissect very quickly what you have—whether it's a hazardous spore preparation or just plain baby powder."
Using donated blood, the researchers were able to find a number of human antibodies that were all highly specific for spores of Bacillus subtilis, a close cousin of Bacillus anthracis which is the causative agent of anthrax, and 11 other types of bacterial spores. Work on Bacillus anthracis itself is currently getting underway.
The researchers found the antibodies using phage display, a method for selecting from billions of antibody variants only those that bind to a particular target. In the technique, the antibody repertoire obtained from white blood cells is fused to a viral coat protein of the phage—a filamentous virus that infects bacteria—to create an antibody "library." Since the phage virus displays the antibodies on the surface of the virion, it makes them easy to select for in vitro by passing the viral stew over a stationary phase containing the target, in this case the Bacillus spores. Those that cannot bind are washed away, while those that bind to the spores are selected.
By attaching a fluorescent chemical to the antibodies, Janda and his colleagues could look under a specially-equipped microscope and quickly determine whether a powdered sample had any spores present. They could even detect a single spore.
"We've shown for the first time that human antibodies can recognize spore surfaces," says Janda, who adds that the antibodies might make a powerful and convenient tool for detecting anthrax.
Moreover, antibodies that bind to spores have important implications for treating individuals who are exposed to anthrax. Since the antibodies come from humans, they could be given to individuals to passively immunize them—the antibodies would help to clear anthrax spores from the individual's system. And, because of the ease of producing and administering antibodies, they represent a simple, inexpensive, and potentially powerful therapy.
The research article "Human antibodies against spores of the genus Bacillus: a model study for detection of and protection against anthrax and the bioterrorist threat" is authored by Bin Zhou, Peter Wirsching, and Kim D. Janda and appears in the April 16, 2002 issue of Proceedings of the National Academy of Sciences.
The research was funded in part by The Skaggs Institute for Chemical Biology.
Materials provided by Scripps Research Institute. Note: Content may be edited for style and length.
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