A Deadly Peek at Fungal Medusa

If looks can kill, why not try look-alikes? Scientists have used a molecular imprint--something akin to a plaster cast--of a fungus-killing compound produced by yeast to make a protein that appears to be lethal to a common fungus that infects people. The finding, reported in next month's issue of Nature Biotechnology, could lead to a therapy for vaginal fungal infections in women and oral fungal infections in AIDS patients.

A team led by Luciano Polonelli, a microbiologist at Università degli Studi de Parma, began its quest for a mirror-image killer with a type of yeast that produces a toxin against fungi that attack it. The toxin itself would be too toxic as a drug for people, so the group took a different tack. They raised antibodies to this toxin in cell culture, then injected the antibodies into a mouse. The mouse immune system, encountering the foreign protein, produced antibodies to the antibodies-tongue twisters that scientists call antiidiotypic antibodies, or anti-Ids.

The scientists isolated from mouse spleen cells 10 anti-Ids. They put the most potent to the test of combating Candida albicans, the culprit behind vaginal fungal infections. Rats infected with Candida and given injections of the anti-Id were cured much faster than were rats given a placebo.

Experts say the preliminary study is promising. "This is the first time I'm aware of where an antibody behaves like an antibiotic," says Neil Greenspan, an immunologist at Case Western Reserve University in Cleveland. The next step would be to do tests in other animal models. Adds Barry Fields, a biochemist at the Center for Advanced Research in Biotechnology at the University of Maryland, "This is certainly promising in terms of therapeutics."