ABSTRACT
Natural killer (NK) cells and dendritic cells (DCs) have been shown to link the innate and adaptive immune systems. Likewise, a new innate cell subset, interferon-producing killer DCs (IKDCs), shares phenotypic and functional characteristics with both DCs and NK cells. Here, we show IKDCs play an essential role in the resolution of experimental autoimmune encephalomyelitis (EAE) upon treatment with the tolerizing agent, myelin oligodendrocyte glycoprotein (MOG), genetically fused to reovirus protein σ1 (termed MOG-pσ1). Activated IKDCs were recruited subsequent MOG-pσ1 treatment of EAE, and disease resolution was abated upon NK1.1 cell depletion. These IKDCs were able to kill activated CD4(+) T cells and mature dendritic DCs, thus, contributing to EAE remission. In addition, IKDCs were responsible for MOG-pσ1-mediated MOG-specific regulatory T cell recruitment to the CNS. The IKDCs induced by MOG-pσ1 expressed elevated levels of HVEM for interactions with cognate ligand-positive cells: LIGHT(+) NK and T(eff) cells and BTLA(+) B cells. Further characterization revealed these activated IKDCs being MHC class II(high), and upon their adoptive transfer (CD11c(+)NK1.1(+)MHC class II(high)), IKDCs, but not CD11c(+)NK1.1(+)MHC class II(intermediate/low) (unactivated) cells, conferred protection against EAE. These activated IKDCs showed enhanced CD107a, PD-L1, and granzyme B expression and could present OVA, unlike unactivated IKDCs. Thus, these results demonstrate the interventional potency induced HVEM(+) IKDCs to resolve autoimmune disease.
Subject(s)
Dendritic Cells/metabolism , Encephalomyelitis, Autoimmune, Experimental/immunology , Encephalomyelitis, Autoimmune, Experimental/therapy , Myelin Proteins/metabolism , Viral Proteins/metabolism , Adoptive Transfer , Animals , Antigens, Ly/metabolism , Cytotoxicity, Immunologic , Dendritic Cells/immunology , Dendritic Cells/pathology , Disease Progression , Encephalomyelitis, Autoimmune, Experimental/pathology , Encephalomyelitis, Autoimmune, Experimental/physiopathology , Immune Tolerance , Interferons/metabolism , Lymphocyte Activation , Mice , Myelin Proteins/genetics , Myelin Proteins/immunology , Myelin-Oligodendrocyte Glycoprotein , NK Cell Lectin-Like Receptor Subfamily B/metabolism , Receptors, Tumor Necrosis Factor, Member 14/metabolism , Recombinant Fusion Proteins/administration & dosage , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/immunology , Recombinant Fusion Proteins/metabolism , Recurrence , T-Lymphocyte Subsets/immunology , T-Lymphocyte Subsets/metabolism , T-Lymphocyte Subsets/pathology , T-Lymphocytes, Regulatory/immunology , T-Lymphocytes, Regulatory/metabolism , T-Lymphocytes, Regulatory/pathology , Viral Proteins/genetics , Viral Proteins/immunologyABSTRACT
To better understand the roles of gammadelta T cells in mucosal infection, we utilized Salmonella enterica serovar Typhimurium (Salmonella serovar Typhimurium) infection in cattle as it closely approximates Salmonella serovar Typhimurium-induced enterocolitis in humans. Protein and gene expression in alphabeta and gammadelta T cells derived from lymphatic ducts draining the gut mucosa in Salmonella serovar Typhimurium-infected calves were analyzed. In calves with enterocolitis, general gene expression trends in gammadelta T cells suggested subtle activation and innate response, whereas alphabeta T cells were relatively quiescent following Salmonella serovar Typhimurium infection. An increase in IL-2R alpha expression on gammadelta T cells from infected calves and results from in vitro assays suggested that gammadelta T cells were primed by Salmonella serovar Typhimurium LPS to better respond to IL-2 and IL-15. Together with gene expression trends in vivo, these data support early priming activation of target tissue gammadelta T cells during Salmonella serovar Typhimurium infection.