Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: September 27, 2013
Publication Date: May 1, 2014
Citation: Maggioli, M.F., Palmer, M.V., Vordermeier, H.M., Whelan, A.O., Waters, W.R. 2014. Polyfunctional CD4 T cells in the response to bovine tuberculosis [abstract]. Journal of Immunology. 192(1):1034(Suppl. 207.6). Technical Abstract: CD4 T cells are crucial in immunity to tuberculosis (TB). Polyfunctional CD4 T cells simultaneously produce interferon-gamma (IFN-gamma), Interleukin-2 (IL-2) and Tumor necrosis factor-alpha (TNF-alpha) and play relevant roles in several chronic infections, including human TB and HIV. However, the assessment of polyfunctional cells in bovine infections was not feasible due to the lack of monoclonal antibodies that recognize biologically active bovine IL-2. Recently, a recombinant human antibody fragment specific for bovine IL-2 enabled the evaluation of polyfunctional T cells in cattle. The objective of the present study was to access antigen-specific polyfunctional ex vivo responses after aerosol Mycobacterium bovis infection of cattle. Peripheral blood mononuclear cells (PBMCs) were collected from infected cattle and stimulated with rESAT-6:CFP-10 (E:C), media or pokeweed (PWM) for 16 hours. After stimulation, the expression of CD4, CD45RO, CCR7, IL-2, IFN-gamma, TNF-alpha and cell viability were analyzed by flow cytometry. The ex vivo response to E:C consisted of 63% effectors (CD4+ CD45RO- CCR7-), 32% effector memory (CD4+ CD45RO+ CCR7-), and 9% central memory (CD4+ CD45RO+ CCR7+) phenotypes. In regard to the cytokine profile, 70% of cells producing cytokines expressed both IFN-gamma and TNF-alpha, 31% expressed all three cytokines, 6% expressed both TNF-alpha and IL-2, and 3% expressed IL-2 and IFN-gamma. Cells producing only IFN-gamma, IL-2, or TNF-alpha represented, 5%, 8% and 1%, respectively. These findings demonstrate that the ex vivo polyfunctional response consists mainly of effector cells co-producing IFN-gamma and TNF-alpha.