David Shepherd

Many chemicals are known or suspected to cause deleterious effects on human health. Studies of pharmaceuticals and environmental contaminants indicate that the toxicity of many chemicals is mediated by a mechanism that involves or affects the immune system. Broadly speaking, chemicals can cause two different types of immune dysfunction: immune suppression, leading to an increased susceptibility to infectious diseases and cancer; and immune enhancement, leading to either autoimmune disease or allergy. While many studies indicate that exposure of humans and laboratory animals to chemicals can induce immune disorders, the mechanisms by which they alter immune function are largely unknown.

Dr. Shepherd's research program currently encompasses two somewhat distinct areas of immunology. The first focus of his laboratory centers on defining the role of the man-made environmental chemicals such as dioxins and PCBs on dendritic cells (DCs), which are considered to be the "professional" antigen presenting cells in the immune system. His research is aimed at elucidating the mechanisms of immune suppression by these toxicants by addressing the role of Aryl hydrocarbon receptor (AhR) activation in DCs and the functional consequences of these alterations. The second area of investigation by this research group aims to develop new immunotherapeutics. Specifically, two novel platforms are being developed that intentionally modulate the AhR: (1) combining AhR agonists and DC-specific antibodies in liposomal nanoparticles to generate targeted immunosuppression, and (2) targeting both DCs and CD4+ T cells with AhR antagonist-loaded nanoparticles to block pollutant-induced immunotoxicity. These studies utilize both in vitro and in vivo models of innate and adaptive immunity.

PHAR 324, Medicinal Plants

PHAR 445, Immunopharmacology

PHAR 342, Physiological Systems II

PHAR 444, Pharmacology/Toxicology II

BMED 644, Immunotoxicology