DANUTA J. HERZYK, PHD, is the Senior Scientific Director in the Safety Assessment Department of Merck Research Laboratories. She previously worked in immunologic toxicology for GlaxoSmithKline. A member of the Society of Toxicology, Drug Information Association, and American Association of Immunologists, Dr. Herzyk has published over forty articles. She serves on the editorial board of Perspectives in Experimental and Clinical Immunotoxicology.

JEANINE L. BUSSIERE, PHD, is an Executive Director of Toxicology at Amgen. She is the author or coauthor of eight book chapters and approximately fifty articles. She is on the editorial board of Journal of Immunotoxicology. Dr. Bussiere is a member of the Society of Toxicology, American College of Toxicology, and Drug Information Association.