Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: August 27, 2013
Publication Date: May 1, 2014
Citation: Maggioli, M.F., Palmer, M.V., Vordermeier, H.M., Whelan, A.O., Waters, W.R. 2014. Bovine central memory T cells are highly proliferative in response to bovine tuberculosis infection [abstract]. Journal of Immunology. 192(1):1033(Suppl. 207.5). Technical Abstract: Long-term (i.e., 14 days) cultured IFN-gamma responses of peripheral blood mononuclear cells are used as a correlate of T cell central memory (Tcm) responses in both humans and cattle. With bovine tuberculosis, vaccine-elicited long-term IFN-gamma ELISPOT assays are a correlate of protection. Recently, it has been described that Tcm cells are responsible for 75% of the long-term IFN-gamma response in cattle. In other species, Tcm possess low activation threshold and are highly proliferative. The objective of the present study was to access the proliferative capability of long-term cultured lymphocytes compared to 6 days cultured lymphocytes (n = 6) in response to aerosol Mycobacterium bovis (M. bovis) infection. For the long-term culturing, PBMCs collected from infected cattle were stimulated with M. bovis purified protein derivative (PPDb), rESAT-6:CFP-10 (E:C) and peptide cocktails of Tb10.4 and Ag85A for 13 days with periodic addition of fresh media and rIL-2. On day 13, cultured PBMC were stained with CellTrace Violet (Invitrogen®) and re-stimulated with medium alone, E:C or pokeweed mitogen (PWM) in the presence of fresh autologous adherent cells for an additional six days (20 days). Cells were analyzed for CD4, CD8, gamma delta TCR, CD45RO and CCR7 expression as well as proliferation via flow cytometry. In response to E:C, ~ 48% of long-term cultured CD4+ cells were proliferative as compared to 27% of the 6d cultured cells (p=0.001). The phenotype distribution for proliferative long-term cultured cells was: ~30% of Tcm phenotype (CCR7+, CD45RO+), ~48% of Tem phenotype (CCR7-, CD45RO+), ~8% of effector cells (CCR7-, CD45RO-) and <1% of naïve phenotype (CCR7+, CD45RO-). The phenotype distribution for proliferative short-term cultured cells was: ~16% of Tcm (p=0.01), ~47% of Tem, ~42% of effector cells (p=0.001) and < 1% of naïve cells. These findings confirm that bovine Tcm cells present high proliferative capability compared with short-term cultured cells.