title: Enhanced secretion of interferon-gamma by bovine gammadelta T cells induced by coculture with Mycobacterium bovis-infected dendritic cells: evidence for reciprocal activating signals.
abstract: Evidence suggests that gammadelta T cells form part of the innate immune response to Mycobacterium bovis infection. Dendritic cells (DCs) are capable of secreting high levels of interleukin-12 (IL-12) following infection with mycobacteria and can induce interferon-gamma (IFN-gamma) secretion by natural killer and gammadelta T cells We investigated the innate interactions occurring between WC1(+)gammadelta T cells and M. bovis-infected DCs. Following coculture with M. bovis-infected DCs, secretion of IFN-gamma and expression of CD25 and major histocompatibility complex class II on WC1(+)gammadelta T cells were significantly enhanced. Reciprocal enhancement of IL-12 secretion by the DCs was also observed and this interaction was found to be contact dependent. We hypothesize that there is an early, transient signal between the WC1(+)gammadelta T cells and the DCs, which promotes the synthesis of biologically active IL-12, and which is dependent upon cell-cell contact. Reciprocal signals including IL-12 are then delivered to WC1(+)gammadelta cells, which leads to the enhanced secretion of IFN-gamma, and the up-regulation of activation markers and antigen presentation molecules by the WC1(+)gammadelta T cells. These interactions are likely to form a critical part of the T helper type 1-conditioning response of DCs to M. bovis.
authors.affiliation: Institute for Animal Health, Compton, Newbury, Berkshire, UK. sally.price@bbsrc.ac.uk
authors.forename: Sally J
authors.initials: SJ
authors.lastname: Price
authors.forename: Jayne C
authors.initials: JC
authors.lastname: Hope
mesh_terms: D000818:Animals; D002417:Cattle; D002450:Cell Communication / Q000276:immunology; D002478:Cells, Cultured; D018920:Coculture Techniques; D003713:Dendritic Cells / Q000276:immunology* / Q000382:microbiology; D000949:Histocompatibility Antigens Class II / Q000378:metabolism; D007371:Interferon-gamma / Q000378:metabolism*; D018664:Interleukin-12 / Q000378:metabolism; D053645:Interleukin-2 Receptor alpha Subunit / Q000378:metabolism; D008213:Lymphocyte Activation / Q000276:immunology; D009163:Mycobacterium bovis / Q000276:immunology; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000032:analysis*; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D014380:Tuberculosis, Bovine / Q000276:immunology*; D015854:Up-Regulation / Q000276:immunology
chemical_list: D000949:Histocompatibility Antigens Class II; D053645:Interleukin-2 Receptor alpha Subunit; D016692:Receptors, Antigen, T-Cell, gamma-delta; D018664:Interleukin-12; D007371:Interferon-gamma