title: Functional and phenotypic characterization of WC1+ gamma/delta T cells isolated from Babesia bovis-stimulated T cell lines.
abstract: Functional studies with WC1+ gamma/delta T cell lines were performed to clarify the role of this subpopulation of gamma/delta T cells in the in vitro immune response to Babesia bovis. As CD4+ T cells decreased and gamma/delta T cells increased in B. bovis-stimulated T cell lines, antigen-specific proliferation declined to background levels. One irradiated gamma/delta T cell line inhibited proliferation of autologous Th1 cells, although unirradiated gamma/delta T cells either synergized with or had no effect on Th cell proliferation. gamma/delta T cells were not cytolytic for bovine alpha/beta T cells, but expressed natural killer (NK)-like cytotoxicity when assayed on xenogeneic NK-sensitive target cells. The gamma/delta T cells were IL-2 dependent and expressed IFN-gamma and TNF-alpha, but not TNF-beta, IL-2, or IL-4 mRNA. Together, these results raise the possibility that WC1+ gamma/delta T cells respond in vitro to autoantigens present on CD4+ T cells or to cytokines secreted by activated CD4+ T cells, resulting in modulation of the CD4+ T cell response and outgrowth of the gamma/delta T cells in parasite-stimulated lines.
authors.affiliation: Department of Veterinary Pathobiology, Texas A & M University, College Station 77843.
authors.forename: W C
authors.initials: WC
authors.lastname: Brown
authors.forename: W C
authors.initials: WC
authors.lastname: Davis
authors.forename: S H
authors.initials: SH
authors.lastname: Choi
authors.forename: D A
authors.initials: DA
authors.lastname: Dobbelaere
authors.forename: G A
authors.initials: GA
authors.lastname: Splitter
mesh_terms: D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D000953:Antigens, Protozoan / Q000276:immunology; D016793:Babesia bovis / Q000276:immunology*; D002417:Cattle; D015815:Cell Adhesion Molecules / Q000378:metabolism; D002460:Cell Line; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D003602:Cytotoxicity, Immunologic; D015870:Gene Expression; D007371:Interferon-gamma / Q000378:metabolism; D019041:L-Selectin; D017493:Leukocyte Common Antigens / Q000032:analysis; D008213:Lymphocyte Activation; D012333:RNA, Messenger / Q000235:genetics; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000276:immunology*; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D000953:Antigens, Protozoan; D015815:Cell Adhesion Molecules; D016207:Cytokines; D012333:RNA, Messenger; D016692:Receptors, Antigen, T-Cell, gamma-delta; D014409:Tumor Necrosis Factor-alpha; D019041:L-Selectin; D007371:Interferon-gamma; D017493:Leukocyte Common Antigens