Application of Long-term cultured Interferon-γ Enzyme-linked Immunospot Assay for Assessing Effector and Memory T Cell Responses in Cattle

• Published in: Journal of visualized experiments no. 101; p. e52833
• Main Authors: Maggioli, Mayara F, Palmer, Mitchell V, Vordermeier, H Martin, Whelan, Adam O, Fosse, James M, Nonnecke, Brian J, Waters, W Ray
• Format: Journal Article
• Language: English
• Published: United States MyJove Corporation 11.07.2015
• Subjects: Animals; Cattle; Cytokines - immunology; Enzyme-Linked Immunospot Assay; Humans; Immunologic Memory; Immunology; Interferon-gamma - immunology; Interferon-gamma Release Tests; Leukocyte Common Antigens - metabolism; Leukocytes, Mononuclear - immunology; Mice; Mycobacterium; Receptors, CCR7 - metabolism; Receptors, Lymphocyte Homing; Simian immunodeficiency virus; T-Lymphocytes - immunology; Tuberculosis, Bovine - diagnosis
• ISSN: 1940-087X; 1940-087X
• DOI: 10.3791/52833

Effector and memory T cells are generated through developmental programing of naïve cells following antigen recognition. If the infection is controlled up to 95 % of the T cells generated during the expansion phase are eliminated (i.e., contraction phase) and memory T cells remain, sometimes for a lifetime. In humans, two functionally distinct subsets of memory T cells have been described based on the expression of lymph node homing receptors. Central memory T cells express C-C chemokine receptor 7 and CD45RO and are mainly located in T-cell areas of secondary lymphoid organs. Effector memory T cells express CD45RO, lack CCR7 and display receptors associated with lymphocyte homing to peripheral or inflamed tissues. Effector T cells do not express either CCR7 or CD45RO but upon encounter with antigen produce effector cytokines, such as interferon-γ. Interferon-γ release assays are used for the diagnosis of bovine and human tuberculosis and detect primarily effector and effector memory T cell responses. Central memory T cell responses by CD4(+) T cells to vaccination, on the other hand, may be used to predict vaccine efficacy, as demonstrated with simian immunodeficiency virus infection of non-human primates, tuberculosis in mice, and malaria in humans. Several studies with mice and humans as well as unpublished data on cattle, have demonstrated that interferon-γ ELISPOT assays measure central memory T cell responses. With this assay, peripheral blood mononuclear cells are cultured in decreasing concentration of antigen for 10 to 14 days (long-term culture), allowing effector responses to peak and wane; facilitating central memory T cells to differentiate and expand within the culture.