Research at the Medical School report that small amounts of environmental pollutants can damage the immune system by triggering the "suicide" of antibody-creating B cells.

Associate professor of pathology David H. Sherr demonstrated that polycyclic aromatic hydrocarbons (PAH), present in automobile exhaust, cigarette smoke and lakes can suppress the immune system at levels 100 to 1000 times less than those at which the compounds are known to cause cancer.

To study "prototypic" environmental pollutants, the researchers grew immature B cells to use as models for eight blood cell types, according to Sherr. The results were published by members of the pathology department in a recent issue of Toxicology and Applied Pharmacology.

Sherr' found that one PAH compound, benzopyrene, causes programmed cell death of B cells through interactions with a DNA-binding protein. This cell death could be related to the pollutants' ability to cause cancer at higher levels, the pathologist said.

Sherr said the study of pollutants effects on the immune system show that compounds previously known to be harmful are more dangerous than scientists expected. The results, Sherr said, could elucidate ways to manipulate the immune system.