ABSTRACT
Previous studies showed a fetal sheep liver extract (FSLE), in association with monophosphoryl lipid A, MPLA (a bioactive component of lipid A of LPS), could interact to induce the development of dendritic cells (DCs) which regulated production of Foxp3+ Treg. This interaction was associated with an altered gene expression both of distinct subsets of TLRs and of CD200Rs. Prior studies had suggested that major interacting components within FSLE were gamma-chain of fetal hemoglobin (Hgbgamma) and glutathione (GSH). We investigated whether differentiation/maturation of DCs in vitro in the presence of either GM-CSF or Flt3L to produce preferentially either immunogenic or tolerogenic DCs was itself controlled by an interaction between MPLA, GSH and Hgbgamma. At low (approximately 10 microg/ml) Hgbgamma concentrations, DCs developing in culture with GSH and MPLA produced optimal stimulation of allogeneic CTL cell responses in vitro (and enhanced skin graft rejection in vivo). At higher concentrations (>40 microg/ml Hgbgamma) and equivalent concentrations of MPLA and GSH, the DCs induce populations of Treg which can suppress the induction of allogeneic CTL and graft rejection in vivo. These different populations of DCs express different patterns of mRNAs for the CD200R family. Addition of anti-TLR or anti-MD-1 mAbs to DCs developing in this mixture (Hgbgamma+GSH+MPLA), suggests that one effect of (GSH+Hgbgamma) on MPLA stimulation may involve altered signaling through TLR4.
Subject(s)
Dendritic Cells/metabolism , Fetal Hemoglobin/metabolism , Glutathione/metabolism , Graft Rejection/immunology , Lipid A/analogs & derivatives , T-Lymphocytes, Regulatory/metabolism , Animals , Antibodies, Blocking , Bone Marrow/pathology , Cell Differentiation , Dendritic Cells/immunology , Dendritic Cells/pathology , Fetal Hemoglobin/immunology , Glutathione/immunology , Graft Rejection/blood , Graft Rejection/pathology , Graft Rejection/prevention & control , Granulocyte-Macrophage Colony-Stimulating Factor/immunology , Granulocyte-Macrophage Colony-Stimulating Factor/metabolism , Histocompatibility Antigens , Immune Tolerance , Immunity, Cellular , Lipid A/immunology , Lipid A/metabolism , Membrane Glycoproteins/genetics , Membrane Glycoproteins/immunology , Membrane Glycoproteins/metabolism , Membrane Proteins/immunology , Membrane Proteins/metabolism , Mice , Mice, Inbred C3H , Mice, Inbred C57BL , Mice, Knockout , Signal Transduction , Skin Transplantation , T-Lymphocytes, Cytotoxic/immunology , T-Lymphocytes, Cytotoxic/metabolism , T-Lymphocytes, Cytotoxic/pathology , T-Lymphocytes, Regulatory/immunology , T-Lymphocytes, Regulatory/pathology , Toll-Like Receptor 4/genetics , Toll-Like Receptor 4/immunology , Toll-Like Receptor 4/metabolismABSTRACT
Previous studies showed a fetal sheep liver extract (FSLE), in association with LPS, injected into aged (>20 months) mice reversed the altered polarization (increased IL-4 and IL-10 with decreased IL-2 and IFN-gamma) in cytokine production seen from ConA stimulated lymphoid cells of those mice. Aged mice show a >60% decline in numbers and suppressive function of both CD4(+)CD25(+)Foxp3(+)Treg and so-called Tr3 (CD4(+)TGFbeta(+)). Their number/function is restored to levels seen in control (8-week-old) mice by FSLE. We have reported at length on the ability of a novel pair of immunoregulatory molecules, members of the TREM family, namely CD200:CD200R, to control development of dendritic cells (DCs) which themselves regulate production of Foxp3(+) Treg. The latter express a distinct subset of TLRs which control their function. We report that a feature of the altered Treg expression following combined treatment with FSLE and monophosphoryl lipid A, MPLA (a bioactive component of lipid A of LPS) is the altered gene expression both of distinct subsets of TLRs and of CD200Rs. We speculate that this may represent one of the mechanisms by which FSLE and MPLA alter immunity in aged mice.
Subject(s)
Aging/immunology , Membrane Glycoproteins/immunology , Receptors, Antigen, T-Cell/immunology , T-Lymphocytes, Regulatory/immunology , Animals , Cells, Cultured , Cytokines/biosynthesis , Cytokines/immunology , Cytotoxicity, Immunologic , Dendritic Cells/immunology , Immunity, Mucosal , Lipid A/analogs & derivatives , Lipid A/immunology , Liver/immunology , Lymphocyte Culture Test, Mixed , Mice , Mice, Inbred C3H , Mice, Inbred C57BL , Peyer's Patches/immunology , Polymerase Chain Reaction/methods , Sheep , Tissue Extracts/immunologyABSTRACT
We have shown previously that a fetal sheep liver extract (FSLE) containing significant quantities of fetal ovine gamma globin chain (Hbgamma) and LPS injected into aged (>20 months) mice could reverse the altered polarization (increased IL-4 and IL-10 with decreased IL-2 and IFNgamma) in cytokine production seen from ConA stimulated lymphoid cells of those mice. The mechanism(s) behind this change in cytokine production were not previously investigated. We report below that aged mice show a >60% decline in numbers and suppressive function of both CD4(+)CD25(+)Foxp3(+) Treg and so-called Tr3 (CD4(+)TGFbeta(+)), and that their number/function is restored to levels seen in control (8-week-old) mice by FSLE. In addition, on a per cell basis, CD4(+)CD25(-)Treg from aged mice were >4-fold more effective in suppression of proliferation and IL-2 production from ConA-activated lymphoid cells of a pool of CD4(+)CD25(-)T cells from 8-week-old mice than similar cells from young animals, and this suppression by CD25(-)T cells was also ameliorated following FSLE treatment. Infusion of anti-TGFbeta and anti-IL-10 antibodies in vivo altered Treg development following FSLE treatment, and attenuated FSLE-induced alterations in cytokine production profiles.
Subject(s)
Aging/immunology , CD4-Positive T-Lymphocytes/immunology , Cytokines/biosynthesis , Liver Extracts/immunology , T-Lymphocytes, Regulatory/immunology , Animals , Concanavalin A/immunology , Concanavalin A/pharmacology , Cytokines/immunology , Globins/immunology , Interleukin-10/immunology , Lipopolysaccharides/immunology , Lipopolysaccharides/pharmacology , Liver Extracts/pharmacology , Mice , Mice, Inbred C57BL , Mitogens/immunology , Sheep , Spleen/cytology , Spleen/immunology , Transforming Growth Factor beta/immunology , Transforming Growth Factor beta/metabolismABSTRACT
Previous reports from our group have established that the fetal ovine gamma globin chain (Hbgamma) and LPS can synergize in the induction of pro-inflammatory cytokines, especially TNFalpha, from mouse and human leukocytes. A fetal sheep liver extract (FSLE) which was observed to have marked immunoregulatory properties in vivo and in vitro had independently been observed to contain significant amounts of each of these molecules. However, the biological activity of this extract (hereafter FSLE) was not explained solely by its content of Hbgamma and LPS, and independent analysis confirmed also the presence of migration inhibitory factor, MIF, and glutathione in FSLE. We have investigated whether MIF and the cellular anti-oxidant glutathione can further synergize with Hbgamma and LPS in TNFalpha induction from human cells in vitro, and mouse cells activated in vivo/in vitro. Our data show that indeed there is evidence for such a synergy. Treatment or mouse cells with FSLE produced an enhanced TNFalpha production which could be inhibited independently both by anti-Hbgamma and by anti-MIF, and optimally by a combination of these reagents.
Subject(s)
Aging/physiology , Glutathione/pharmacology , Hemoglobins/metabolism , Leukocytes/drug effects , Lipopolysaccharides/pharmacology , Macrophage Migration-Inhibitory Factors/pharmacology , Recombinant Proteins/pharmacology , Tumor Necrosis Factor-alpha/biosynthesis , Animals , Cell Extracts/chemistry , Cell Extracts/pharmacology , Cell Polarity , Cells, Cultured , Fetal Blood/metabolism , Health , Heme/metabolism , Hemoglobins/isolation & purification , Humans , Leukocytes/metabolism , Liver/cytology , Liver/metabolism , Macrophage Migration-Inhibitory Factors/immunology , Mice , Mice, Inbred C57BL , Recombinant Proteins/immunology , SheepABSTRACT
We have reported earlier that purified preparations of sheep fetal hemoglobin, but not adult hemoglobin, in concert with non-stimulatory doses of lipopolysaccharide (LPS) (lipid A), act cooperatively to regulate in vitro production of a number of cytokines, including TNFalpha, TGFbeta and IL-6 from murine and human leukocytes. Following in vivo treatment of mice with the same combination of hemoglobin and LPS, harvested spleen or peritoneal cells showed a similar augmented capacity to release these cytokines into culture supernatants. We report below that genetically cloned gamma-chain of human or sheep fetal hemoglobin, but not cloned alpha- or beta-chains, can produce this cooperative effect, as indeed can HPLC purified, heme-free, gamma-chains derived from cord blood fetal hemoglobin, and that purified haptoglobin completely abolishes the cooperative interaction.