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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Infectious Bacterial Diseases Research » Research » Publications at this Location » Publication #311352
Title: Characterization of effector and memory T cell subsets in the immune response to bovine tuberculosis in cattle

Author
item MAGGIOLI, MAYARA - Iowa State University
item Palmer, Mitchell
item Thacker, Tyler
item VORDERMEIER, H - Veterinary Laboratories Agency (VLA)
item Waters, Wade

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/17/2015
Publication Date: 4/16/2015
Publication URL: http://handle.nal.usda.gov/10113/60720
Citation: Maggioli, M.F., Palmer, M.V., Thacker, T.C., Vordermeier, H.M., Waters, W.R. 2015. Characterization of effector and memory T cell subsets in the immune response to bovine tuberculosis in cattle. PLoS One. 10(4):e0122571.

Interpretive Summary: Despite highly successful eradication efforts in several countries, tuberculosis of cattle remains a serious health concern worldwide. In addition, recent outbreaks of tuberculosis in various states demonstrate that the disease is far from eliminated from the United States. Improved techniques are needed for detection of infected cattle as well as improved control strategies (e.g., vaccines). To develop improved tests and vaccines, it is beneficial to first understand the nature of bovine immune responses to the pathogen. In this study, important cell types involved in memory immune response of cattle to various infectious agents was characterized. This basic information will be useful for development of improved tests and vaccines for cattle.

Technical Abstract: Vaccine-elicited long-term cultured IFN-gamma ELISPOT responses correlate with protection against bovine tuberculosis in cattle. With humans, cultured IFN-gamma ELISPOT assays are primarily a measure of central memory T cell (Tcm) responses; however, this important subset of lymphocytes is poorly characterized in cattle. The objective of the present study was to characterize the relative contribution of Tcm (CCR7+, CD62Lhi, CD45RO+), T effector memory (Tem, defined as: CCR7-, CD62Llow/int, CD45RO+), and T effector cells (CCR7-, CD62L-/low, CD45RO-), in the immune response to Mycobacterium bovis. Peripheral blood mononuclear cells (PBMC) from infected cattle were stimulated with a cocktail of purified protein derivative (PPDb), rTb10.4 and rAg85A for 13 days with periodic addition of fresh media and rIL-2. On day 13, cultured PBMC were re-stimulated with medium alone, rESAT-6:CFP10 or PPDb with fresh autologous adherent cells for antigen presentation. Cultured cells (13 days) or fresh PBMCs (ex vivo response) from the same calves were analyzed for IFN-gamma production, proliferation, and CD4, CD45RO, CD62L, CD44, and CCR7 expression via flow cytometry after overnight stimulation. In response to mycobacterial antigens, ~75% of CD4+ IFN-gamma+ cells in long-term cultures expressed a Tcm phenotype while less than 10% of the ex vivo response consisted of Tcm cells. Upon re-exposure to antigen, long-term cultured cells were highly proliferative, a distinctive characteristic of Tcm, and the predominant phenotype within the long-term cultures switched from Tcm to Tem. These finding suggest that proliferative responses of Tcm cells to some extent occurs simultaneously with reversion to effector phenotypes (mostly Tem). The present study demonstrates the existence of bovine Tcm cells and their participation in the response to M. bovis infection.