Notebook

Peanuts may be losing their bite

PEANUT ALLERGY VACCINE Peanuts are more than just an annoyance on airplanes--for a few dozen people each year, they cause deadly anaphylactic shock. The only protection is knowledge of one's allergy and avoidance of the offending food. But most peanut-associated allergic deaths occur from peanut extracts added to prepared foods--additives that sometimes remain unlisted on labels. A peanut allergy vaccine could prevent such deaths. Kam Leong, a professor of biomedical engineering at the Johns Hopkins University School of Medicine and coworkers encapsulated a plasmid-borne gene encoding a major peanut antigen in the biodegradable polysaccharide and crustacean-extract chitosan, and fed it to sensitized mice. "The DNA is delivered to cells lining the gastrointestinal tract. The gene product of this DNA is the peanut allergen, which after processing by the cells is presented to the immune system. Acting as a vaccine, this processed allergen is...