VA Nebraska Iowa Health Care System 1 article published in JoVE Immunology and Infection Assessment of Lymphocyte Migration in an Ex Vivo Transmigration System Kristi J. Warren1,3, Todd A. Wyatt2,3,4 1Department of Internal Medicine, University of Utah, 2Research Service, VA Nebraska Iowa Health Care System, 3Department of Internal Medicine, University of Nebraska Medical Center, 4Department of Environmental, Agricultural & Occupational Health, University of Nebraska Medical Center In this protocol, lymphocytes are placed in the top chamber of a transmigration system, separated from the bottom chamber by a porous membrane. Chemokine is added to the bottom chamber, which induces active migration along a chemokine gradient. After 48 h, lymphocytes are counted in both chambers to quantitate transmigration.