UK Veterinary Laboratories Agency 1 article published in JoVE Immunology and Infection Application of Long-term cultured Interferon-γ Enzyme-linked Immunospot Assay for Assessing Effector and Memory T Cell Responses in Cattle Mayara F. Maggioli1,2, Mitchell V. Palmer1, H. Martin Vordermeier3, Adam O. Whelan3, James M. Fosse4, Brian J. Nonnecke1, W. Ray Waters1 1Infectious Bacterial Diseases Research Unit, National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, 2Department of Veterinary Pathology, College of Veterinary Medicine, Iowa State University, 3UK Veterinary Laboratories Agency, 4Visual Services, National Centers for Animal Health, Animal and Plant Health Inspection Service, United States Department of Agriculture Long-term cultured interferon-γ enzyme-linked immunospot assay is used as a measure of central memory responses and correlates with protective anti-mycobacterial vaccine responses. With this assay, peripheral blood mononuclear cells are stimulated with mycobacterial antigens and interleukin-2 for 14 days, enabling differentiation and expansion of central memory T cells.