Response of bovine gammadelta T cells to activation through CD3.
Since the T cell receptor of gammadelta T cells is associated with CD3 molecules, it is a reasonable postulate that signal transduction through CD3 would occur in gammadelta T cells as it does in alphabeta T cells. However, while a small percentage of bovine gammadelta T cells divided in cultures of peripheral blood mononuclear cells (PBMCs) in response to stimulation by anti-CD3 monoclonal antibody (mAb) the majority of viable gammadelta T cells at the end of the culture period had not. This was assessed by carboxyfluorescein succinimidyl ester (CFSE) loading of cells and flow cytometric analysis here and previously [Res. Vet. Sci. 69 (2000) 275]. When intracytoplasmic staining for interferon-gamma (IFN-gamma) was also used here to assess activation through CD3, a small proportion of gammadelta T cells (approximately 14%) produced IFN-gamma during the first 4 h of culture and by 72 h of culture that number had doubled. By comparison, a much larger proportion of CD4 and CD8 T cells stimulated with anti-CD3 mAb divided and although the percentage of CD4 and CD8 T cells that produced IFN-gamma at 4 h was similar to that of gammadelta T cells, by 72 h the majority of CD4 and CD8 T cells were IFN-gamma(+). Addition of IL-2 did not increase the proportion of gammadelta T cells that responded to anti-CD3 stimulation by cell division. To test the hypothesis that gammadelta T cells were inhibited from responding by other mononuclear cell populations within PBMC, monocytes were removed from the PBMC or gammadelta T cells were purified by magnetic-bead sorting. Only a small distinct population of the sorted cells underwent multiple cell divisions in response to anti-CD3 mAb and removal of monocytes resulted in only a moderate increase in gammadelta T cell replication. The anti-CD3 mAb stimulation system may provide a useful system to evaluate the difference in the requirements for activation and clonal expansion for gammadelta T cells versus alphabeta T cells.
Sathiyaseelan
T
T
Paige Laboratory, Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA 01003, USA.
Rogers
Aric
A
Baldwin
Cynthia L
CL
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D017252:CD3 Complex / Q000276:immunology*; D002417:Cattle; D002455:Cell Division; D007371:Interferon-gamma / Q000096:biosynthesis / Q000276:immunology; D008213:Lymphocyte Activation; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000276:immunology*; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology* / Q000378:metabolism
D000911:Antibodies, Monoclonal; D017252:CD3 Complex; D016692:Receptors, Antigen, T-Cell, gamma-delta; D007371:Interferon-gamma