Researchers to study pollution effects
on human immune systems

Dendritic cells look like something that escaped from a 1950s horror movie — gooey monsters with grasping tentacles that sprout in every direction.

They may look creepy, but UM researcher David Shepherd says they are among our best friends. In fact, without these specialized white blood cells our immune systems would be paralyzed in the face of foreign invaders.

“The reason they are shaped like that is that it helps them grab onto pathogens or microorganisms that cause infectious diseases,” said Shepherd, an assistant professor in UM’s Department of Biomedical and Pharmaceutical Sciences. “They grab onto them and destroy them. They eat them.”

However, these beneficial little monsters may be getting harmed by environmental pollutants — things like polychlorinated biphenyls (PCBs) and dioxin — which suppress the immune system and compromise human health. Shepherd’s UM lab has landed a five-year, $1.6 million grant from the National Institutes of Health to study the issue.

Shepherd said most of the harmful chemicals they study are industrial by-products that can persist in the environment for 10 years or more. He said the grant will help his lab evaluate the health effects of exposure to these types of chemicals and potentially find ways to bolster the immune system to help people fight off infectious diseases or cancer.

But there is a flip side. Sometimes the immune system becomes hyperactive, which can lead to autoimmune diseases and allergies. Shepherd said the pollutants they study contain chemicals that could be used to knock down overactive immune systems, helping people with such disorders.