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1.
Viruses ; 13(2)2021 02 23.
Article in English | MEDLINE | ID: mdl-33672319

ABSTRACT

Respiratory syncytial virus (RSV) infection can cause bronchiolitis, pneumonia, morbidity, and some mortality, primarily in infants and the elderly, for which no vaccine is available. The RSV attachment (G) protein contains a central conserved domain (CCD) with a CX3C motif implicated in the induction of protective antibodies, thus vaccine candidates containing the G protein are of interest. This study determined if mutations in the G protein CCD would mediate immunogenicity while inducing G protein CX3C-CX3CR1 blocking antibodies. BALB/c mice were vaccinated with structurally-guided, rationally designed G proteins with CCD mutations. The results show that these G protein immunogens induce a substantial anti-G protein antibody response, and using serum IgG from the vaccinated mice, these antibodies are capable of blocking the RSV G protein CX3C-CX3CR1 binding while not interfering with CX3CL1, fractalkine.


Subject(s)
CX3C Chemokine Receptor 1/immunology , Chemokines, CX3C/immunology , Respiratory Syncytial Virus Infections/prevention & control , Respiratory Syncytial Virus Vaccines/immunology , Respiratory Syncytial Virus, Human/immunology , Viral Envelope Proteins/genetics , Viral Envelope Proteins/immunology , Animals , Antibodies, Blocking/immunology , Antibodies, Viral/immunology , CX3C Chemokine Receptor 1/genetics , Chemokines, CX3C/genetics , Female , Humans , Mice , Mice, Inbred BALB C , Mutation , Protein Domains , Respiratory Syncytial Virus Infections/immunology , Respiratory Syncytial Virus Infections/virology , Respiratory Syncytial Virus Vaccines/administration & dosage , Respiratory Syncytial Virus Vaccines/chemistry , Respiratory Syncytial Virus Vaccines/genetics , Respiratory Syncytial Virus, Human/chemistry , Respiratory Syncytial Virus, Human/genetics , Viral Envelope Proteins/chemistry
2.
J Virol ; 91(10)2017 05 15.
Article in English | MEDLINE | ID: mdl-28275196

ABSTRACT

Respiratory syncytial virus (RSV) belongs to the family Paramyxoviridae and is the single most important cause of serious lower respiratory tract infections in young children, yet no highly effective treatment or vaccine is available. Through a CX3C chemokine motif (182CWAIC186) in the G protein, RSV binds to the corresponding chemokine receptor, CX3CR1. Since RSV binding to CX3CR1 contributes to disease pathogenesis, we investigated whether a mutation in the CX3C motif by insertion of an alanine, A186, within the CX3C motif, mutating it to CX4C (182CWAIAC187), which is known to block binding to CX3CR1, might decrease disease. We studied the effect of the CX4C mutation in two strains of RSV (A2 and r19F) in a mouse challenge model. We included RSV r19F because it induces mucus production and airway resistance, two manifestations of RSV infection in humans, in mice. Compared to wild-type (wt) virus, mice infected with CX4C had a 0.7 to 1.2 log10-fold lower virus titer in the lung at 5 days postinfection (p.i.) and had markedly reduced weight loss, pulmonary inflammatory cell infiltration, mucus production, and airway resistance after challenge. This decrease in disease was not dependent on decrease in virus replication but did correspond to a decrease in pulmonary Th2 and inflammatory cytokines. Mice infected with CX4C viruses also had higher antibody titers and a Th1-biased T cell memory response at 75 days p.i. These results suggest that the CX4C mutation in the G protein could improve the safety and efficacy of a live attenuated RSV vaccine.IMPORTANCE RSV binds to the corresponding chemokine receptor, CX3CR1, through a CX3C chemokine motif (182CWAIC186) in the G protein. RSV binding to CX3CR1 contributes to disease pathogenesis; therefore, we investigated whether a mutation in the CX3C motif by insertion of an alanine, A186, within the CX3C motif, mutating it to CX4C (182CWAIAC187), known to block binding to CX3CR1, might decrease disease. The effect of this mutation and treatment with the F(ab')2 form of the anti-RSV G 131-2G monoclonal antibody (MAb) show that mutating the CX3C motif to CX4C blocks much of the disease and immune modulation associated with the G protein and should improve the safety and efficacy of a live attenuated RSV vaccine.


Subject(s)
Chemokines, CX3C/metabolism , GTP-Binding Proteins/genetics , Mutation , Respiratory Syncytial Virus Infections/immunology , Respiratory Syncytial Virus Vaccines/adverse effects , Respiratory Syncytial Virus Vaccines/immunology , Respiratory Syncytial Virus, Human/immunology , Animals , Antibodies, Viral/blood , Antibodies, Viral/immunology , Chemokines, CX3C/genetics , Chemokines, CX3C/immunology , Female , GTP-Binding Proteins/chemistry , GTP-Binding Proteins/immunology , Humans , Immunologic Memory , Lung/virology , Mice , Mice, Inbred BALB C , Protein Interaction Domains and Motifs , Respiratory Syncytial Virus Vaccines/chemistry , Respiratory Syncytial Virus Vaccines/genetics , Respiratory Syncytial Virus, Human/genetics , Respiratory Syncytial Virus, Human/physiology , Th1 Cells , Th2 Cells , Vaccines, Attenuated/chemistry , Vaccines, Attenuated/genetics , Vaccines, Attenuated/immunology , Virus Replication
3.
J Virol ; 87(24): 13466-79, 2013 Dec.
Article in English | MEDLINE | ID: mdl-24089561

ABSTRACT

Respiratory syncytial virus (RSV) is a major cause of severe lower respiratory infection in infants and young children and causes disease in the elderly and persons with compromised cardiac, pulmonary, or immune systems. Despite the high morbidity rates of RSV infection, no highly effective treatment or vaccine is yet available. The RSV G protein is an important contributor to the disease process. A conserved CX3C chemokine-like motif in G likely contributes to the pathogenesis of disease. Through this motif, G protein binds to CX3CR1 present on various immune cells and affects immune responses to RSV, as has been shown in the mouse model of RSV infection. However, very little is known of the role of RSV CX3C-CX3CR1 interactions in human disease. In this study, we use an in vitro model of human RSV infection comprised of human peripheral blood mononuclear cells (PBMCs) separated by a permeable membrane from human airway epithelial cells (A549) infected with RSV with either an intact CX3C motif (CX3C) or a mutated motif (CX4C). We show that the CX4C virus induces higher levels of type I/III interferon (IFN) in A549 cells, increased IFN-α and tumor necrosis factor alpha (TNF-α) production by human plasmacytoid dendritic cells (pDCs) and monocytes, and increased IFN-γ production in effector/memory T cell subpopulations. Treatment of CX3C virus-infected cells with the F(ab')2 form of an anti-G monoclonal antibody (MAb) that blocks binding to CX3CR1 gave results similar to those with the CX4C virus. Our data suggest that the RSV G protein CX3C motif impairs innate and adaptive human immune responses and may be important to vaccine and antiviral drug development.


Subject(s)
Epithelial Cells/immunology , Leukocytes, Mononuclear/immunology , Respiratory Syncytial Virus Infections/immunology , Respiratory Syncytial Virus, Human/immunology , Viral Proteins/immunology , Adaptive Immunity , Amino Acid Motifs , CX3C Chemokine Receptor 1 , Chemokines, CX3C/immunology , Epithelial Cells/virology , Humans , Immunity, Innate , Interferons/genetics , Interferons/immunology , Leukocytes, Mononuclear/virology , Receptors, Chemokine/immunology , Respiratory Syncytial Virus Infections/genetics , Respiratory Syncytial Virus Infections/virology , Respiratory Syncytial Virus, Human/chemistry , Respiratory Syncytial Virus, Human/genetics , Viral Proteins/chemistry , Viral Proteins/genetics
4.
PLoS One ; 8(9): e74905, 2013.
Article in English | MEDLINE | ID: mdl-24040360

ABSTRACT

Nanoparticle vaccines were produced using layer-by-layer fabrication and incorporating respiratory syncytial virus (RSV) G protein polypeptides comprising the CX3C chemokine motif. BALB/c mice immunized with G protein nanoparticle vaccines produced a neutralizing antibody response that inhibited RSV replication in the lungs following RSV challenge. ELISPOT analysis showed that G nanoparticle vaccinated mice had increased levels of RSV G protein-specific IL-4 and IFN-γ secreting cells compared to controls following RSV challenge. Remarkably, RSV challenge of G protein nanoparticle vaccinated mice resulted in increased RSV M2-specific IL-4 and IFN-γ secreting T cells, and increased M2-specific H-2Kd-tetramer positive CD8(+) T cells in the lungs compared to controls. Cell type analysis showed vaccination was not associated with increased pulmonary eosinophilia following RSV challenge. These results demonstrate that vaccination of mice with the RSV G protein nanoparticle vaccines induces a potent neutralizing antibody response, increased G protein- and M2-specific T cell responses, and a reduction in RSV disease pathogenesis.


Subject(s)
Nanoparticles/chemistry , Respiratory Syncytial Virus Infections/immunology , Respiratory Syncytial Virus Vaccines/immunology , Viral Fusion Proteins/immunology , Animals , Antibodies, Neutralizing/blood , Bronchoalveolar Lavage , CD8-Positive T-Lymphocytes/immunology , Chemokines, CX3C/immunology , Epitopes/immunology , Female , Interferon-gamma/metabolism , Interleukin-4/metabolism , Lung/virology , Mice , Mice, Inbred BALB C , Respiratory Syncytial Virus Infections/prevention & control , Respiratory Syncytial Virus Vaccines/therapeutic use , Respiratory Syncytial Viruses , Th1 Cells/immunology , Th2 Cells/immunology
5.
J Virol ; 84(2): 1148-57, 2010 Jan.
Article in English | MEDLINE | ID: mdl-19864390

ABSTRACT

Respiratory syncytial virus (RSV) infection causes substantial morbidity and some deaths in the young and elderly worldwide. There is no safe and effective vaccine available, although it is possible to reduce the hospitalization rate for high-risk children by anti-RSV antibody prophylaxis. RSV has been shown to modify the immune response to infection, a feature linked in part to RSV G protein CX3C chemokine mimicry. This study determined if vaccination with G protein polypeptides or peptides spanning the central conserved region of the G protein could induce antibodies that blocked G protein CX3C-CX3CR1 interaction and disease pathogenesis mediated by RSV infection. The results show that mice vaccinated with G protein peptides or polypeptides containing the CX3C motif generate antibodies that inhibit G protein CX3C-CX3CR1 binding and chemotaxis, reduce lung virus titers, and prevent body weight loss and pulmonary inflammation. The results suggest that RSV vaccines that induce antibodies that block G protein CX3C-CX3CR1 interaction may offer a new, safe, and efficacious RSV vaccine strategy.


Subject(s)
Antibodies, Viral/blood , Chemokines, CX3C/metabolism , Receptors, Chemokine/metabolism , Respiratory Syncytial Virus Infections , Respiratory Syncytial Virus Vaccines , Viral Fusion Proteins/immunology , Animals , Antibodies, Viral/immunology , CX3C Chemokine Receptor 1 , Cell Line , Chemokines, CX3C/immunology , Chemotaxis, Leukocyte/immunology , Female , Humans , Inflammation/immunology , Inflammation/prevention & control , Lung/immunology , Lung/physiopathology , Lung/virology , Mice , Mice, Inbred BALB C , Peptides/chemical synthesis , Peptides/chemistry , Peptides/immunology , Receptors, Chemokine/immunology , Respiratory Syncytial Virus Infections/immunology , Respiratory Syncytial Virus Infections/physiopathology , Respiratory Syncytial Virus Infections/virology , Respiratory Syncytial Virus Vaccines/administration & dosage , Respiratory Syncytial Virus Vaccines/immunology , Respiratory Syncytial Virus, Human/immunology , Respiratory Syncytial Virus, Human/pathogenicity , Respiratory Syncytial Virus, Human/physiology , Vaccination , Viral Fusion Proteins/chemistry , Viral Fusion Proteins/metabolism , Virus Replication
6.
Vaccine ; 25(23): 4554-63, 2007 Jun 06.
Article in English | MEDLINE | ID: mdl-17493713

ABSTRACT

Upon antigenic stimulation, establishment of adaptive immune responses that determines vaccine efficacy is dependent on efficient T cell priming. Here, single CX3CL1-Ig DNA administration, a unique ligand of CX3CR1, together with viral or tumor antigens induced a strong in vivo antigen-specific T cell proliferation and effector function that was enough efficient to protect against a tumor challenge. We also showed that early expression of CX3CL1-Ig and antigens in muscle and lymphoid organs induces an increased in vivo migration of myeloid CD14+CD11c+ DC but not lymphoid CD8alpha+CD11c+ DC at these sites. Thus, by effectively directing DC toward lymphoid organs to encounter T cells, CX3CL1-Ig become a new candidate that augments T cell priming and increases efficiency of vaccination.


Subject(s)
Chemokines, CX3C/immunology , Immunoglobulins/immunology , Membrane Proteins/immunology , T-Lymphocytes/immunology , Vaccines, DNA/immunology , Animals , Cell Line , Cell Movement , Chemokine CX3CL1 , Chemokines, CX3C/genetics , Dendritic Cells/physiology , Immunoglobulins/genetics , Interferon-gamma/biosynthesis , Killer Cells, Natural/immunology , Lymphocyte Activation , Membrane Proteins/genetics , Mice , Mice, Inbred C57BL , Ovalbumin/immunology , Vaccination
8.
Gastroenterology ; 132(1): 139-53, 2007 Jan.
Article in English | MEDLINE | ID: mdl-17241867

ABSTRACT

BACKGROUND & AIMS: Fractalkine (FKN/CX3CL1) is a unique chemokine combining adhesive and chemotactic properties. We investigated FKN production by the mucosal microvasculature in inflammatory bowel disease (IBD), its capacity for leukocyte recruitment into the gut, and the number of CX3CR1+ cells in the circulation and mucosa of IBD patients. METHODS: The expression of FKN by human intestinal microvascular endothelial cells (HIMECs) and CX3CR1 by circulating cells was evaluated by flow cytometry, and mucosal CX3CR1+ cells were enumerated by immunohistochemistry. The capacity of FKN to mediate leukocyte binding to HIMECs was assessed by immunoblockade, and to induce HIMEC transmigration by a Transwell system. RESULTS: The spontaneously low HIMEC FKN expression was enhanced markedly by tumor necrosis factor-alpha plus interferon-gamma stimulation, or direct leukocyte contact. This effect was significantly stronger in IBD than control HIMECs. Up-regulation of HIMEC FKN expression was dependent on p38 and extracellular signal-regulated kinase phosphorylation, as was abrogated by selective mitogen-activated protein kinase inhibitors. Circulating T cells contained significantly higher numbers of CX3CR1+ cells in active IBD than inactive IBD or healthy subjects, and IBD mucosa contained significantly more CX3CR1+ cells than control mucosa. Antibody-blocking experiments showed that FKN was a major contributor to T- and monocytic-cell adhesion to HIMECs. Finally, FKN enhanced the expression of active beta1 integrin on leukocytes and mediated leukocyte HIMEC transmigration. CONCLUSIONS: In view of the capacity of FKN to mediate leukocyte adhesion, chemoattraction, and transmigration, its increased production by mucosal microvascular cells and increased numbers of circulating and mucosal CX3CR1+ cells in IBD point to a significant role of FKN in disease pathogenesis.


Subject(s)
Cell Movement/immunology , Chemokines, CX3C/metabolism , Endothelial Cells/cytology , Inflammatory Bowel Diseases/immunology , Membrane Proteins/metabolism , Receptors, Chemokine/metabolism , T-Lymphocytes/cytology , CX3C Chemokine Receptor 1 , Cell Adhesion/immunology , Cells, Cultured , Chemokine CX3CL1 , Chemokines, CX3C/immunology , Cytokines/pharmacology , Endothelial Cells/drug effects , Endothelial Cells/immunology , Flow Cytometry , Humans , Inflammatory Bowel Diseases/pathology , Integrin beta1/metabolism , Intestinal Mucosa/blood supply , Intestinal Mucosa/immunology , Jurkat Cells , MAP Kinase Signaling System/immunology , Membrane Proteins/immunology , Mitogen-Activated Protein Kinase 1/metabolism , Mitogen-Activated Protein Kinase 3/metabolism , Receptors, Cell Surface/metabolism , Receptors, Chemokine/immunology , T-Lymphocytes/immunology , T-Lymphocytes/metabolism , Up-Regulation/immunology , p38 Mitogen-Activated Protein Kinases/metabolism
9.
J Leukoc Biol ; 81(1): 176-85, 2007 Jan.
Article in English | MEDLINE | ID: mdl-17053165

ABSTRACT

Coincidence of the beneficial graft-vs.-tumor (GVT) effects and the detrimental graft-vs.-host disease (GVHD) remains the major obstacle against the widespread use of allogeneic bone marrow transplantation (BMT) as tumor immunotherapy. We here demonstrate that intervention of MAdCAM-1 (mucosal vascular addressin cell adhesion molecule-1) or fractalkine/CX3CL1 after the expansion of allo-reactive donor CD8 T cells selectively inhibits the recruitment of effector donor CD8 T cells to the intestine and alleviates the graft-vs.-host reaction (GVHR) associated intestinal injury without impairing GVT effects. In a nonirradiated acute GVHD model, donor CD8 T cells up-regulate the expression of intestinal homing receptor alpha4beta7 and chemokine receptors CXCR6 and CX3CR1, as they differentiate into effector cells and subsequently infiltrate into the intestine. Administration of anti-MAdCAM-1 antibody or anti-fractalkine antibody, even after the expansion of alloreactive donor CD8 T cells, selectively reduced the intestine-infiltrating donor CD8 T cells and the intestinal crypt cell apoptosis without affecting the induction of donor derived anti-host CTL or the infiltration of donor CD8 T cells in the hepatic tumor. Moreover, in a clinically relevant GVHD model with myeloablative conditioning, these antibodies significantly improved the survival and loss of weight without impairing the beneficial GVT effects. Thus, interruption of alpha4beta7-MAdCAM-1 or CX3CR1-fractalkine interactions in the late phase of GVHD would be a novel therapeutic approach for the separation of GVT effects from GVHR-associated intestinal injury.


Subject(s)
Cell Adhesion Molecules/physiology , Chemokines, CX3C/physiology , Graft vs Host Disease/pathology , Graft vs Host Reaction/immunology , Graft vs Tumor Effect/immunology , Intestines/pathology , Membrane Proteins/physiology , Animals , Antibodies/pharmacology , Biological Transport , CD8-Positive T-Lymphocytes/immunology , Chemokine CX3CL1 , Chemokines, CX3C/immunology , Intestines/immunology , Membrane Proteins/immunology , Mice , Mice, Inbred C57BL , Mucoproteins
11.
J Leukoc Biol ; 80(5): 1156-64, 2006 Nov.
Article in English | MEDLINE | ID: mdl-17056766

ABSTRACT

The CD16+ subset of peripheral blood monocytes (Mo) is expanded dramatically during inflammatory conditions including sepsis, HIV-1 infection, and cancer. CD16+ express high levels of CX3CR1, which mediates arrest onto CX3CL1-expressing endothelial cells (EC) under flow conditions. In contrast, attachment of CD16- Mo onto cytokine-activated EC is independent of CX3CL1. Here, we investigate the ability of CD16+ and CD16- Mo to produce proinflammatory cytokines upon interaction with CX3CL1-expressing HUVEC. We demonstrate that CD16+ but not CD16- Mo produce high levels of IL-6, CCL2, and matrix metalloproteinase (MMP)-9 when cocultured with TNF/IFN-gamma-activated HUVEC or nonactivated HUVEC expressing CX3CL1. Furthermore, supernatants from Mo cocultured with cytokine-activated HUVEC induce neuronal death in vitro. These results suggest that membrane-bound CX3CL1 stimulates production of IL-6, CCL2, and MMP-9 by CD16+ Mo, likely via engagement of CX3CR1. Thus, expansion of CD16+ Mo and their accumulation onto CX3CL1-expressing EC may result in recruitment of Mo and T cell subsets at sites of inflammation in response to CCL2, IL-6-induced cell activation and/or differentiation, and MMP-9-mediated vascular and tissue injury.


Subject(s)
Chemokine CCL2/biosynthesis , Chemokines, CX3C/biosynthesis , Endothelial Cells/immunology , Interleukin-6/biosynthesis , Matrix Metalloproteinase 9/biosynthesis , Membrane Proteins/biosynthesis , Monocytes/immunology , Cell Communication/immunology , Cells, Cultured , Chemokine CCL2/immunology , Chemokine CX3CL1 , Chemokines, CX3C/immunology , Humans , Interleukin-6/immunology , Matrix Metalloproteinase 9/immunology , Membrane Proteins/immunology , Receptors, IgG/biosynthesis , Receptors, IgG/immunology
12.
Exp Dermatol ; 15(11): 900-3, 2006 Nov.
Article in English | MEDLINE | ID: mdl-17002687

ABSTRACT

CX3CL1 is a chemoattractant and adhesion molecule that induces the redistribution of CX3CR1-positive inflammatory leucocytes to sites of inflammation. As a consequence of their increased expression in plaques of psoriasis, and location within genomic regions previously linked to this disease, CX3CL1, and its receptor CX3CR1, represent attractive positional and functional 'psoriasis susceptibility genes'. To investigate the CX3CL1-CX3CR1 system in psoriasis, eight single nucleotide polymorphisms (SNPs) in CX3CL1 and two SNPs in CX3CR1 were genotyped in 281 psoriasis patients and 184 unrelated controls. Allele, genotype and estimated haplotype frequencies were then compared between experimental groups. Allele frequency differences between healthy volunteers and psoriasis patients revealed associations with two CX3CR1 SNPs (hCV11578468, P = 0.03 and c_5687_1, P = 0.04). No associations were observed between CX3CL1 SNPs and psoriasis. These results support a role for the CX3CL1-CX3CR1 system in the pathogenesis of psoriasis and identify SNPs within the chemokine receptors that are associated with the disease.


Subject(s)
Chemokines, CX3C/genetics , Membrane Proteins/genetics , Psoriasis/genetics , Receptors, Chemokine/genetics , Adult , CX3C Chemokine Receptor 1 , Chemokine CX3CL1 , Chemokines, CX3C/immunology , Female , Gene Frequency , Genotype , Humans , Male , Membrane Proteins/immunology , Polymorphism, Single Nucleotide , Psoriasis/immunology , Receptors, Chemokine/immunology
13.
Neuropharmacology ; 51(4): 816-21, 2006 Sep.
Article in English | MEDLINE | ID: mdl-16815480

ABSTRACT

This work reports the effect of chemokine fractalkine/CX3CL1, an endogenous small peptide highly expressed in the central nervous system, on evoked synaptic responses investigated in mouse CA1 stratum radiatum using an electrophysiological approach. We report that in acute mouse hippocampal slices, superfusion of CX3CL1 resulted in a reversible depression of the field excitatory postsynaptic potential (fEPSP) which developed within few seconds, increased for up to 10 min of application and disappeared within 30 min after the end of CX3CL1 treatment. We also show that CX3CL1-induced synaptic depression is (i) dose-dependent with IC50 and nH values of 0.7 nM and 1, respectively, (ii) not associated with a change in paired-pulse facilitation, (iii) mediated through CX3CL1 receptor (CX3CR1), being absent in CX3CR1-/- mice and inhibited in wild-type mice by a specific blocking antibody, and (iv) occluded by the induction of homosynaptic long-term depression (LTD). We conclude that CX3CL1 is a potent neuromodulator of the evoked excitatory synaptic transmission, sharing common mechanisms with LTD.


Subject(s)
Excitatory Postsynaptic Potentials/physiology , Hippocampus/physiology , Receptors, Chemokine/physiology , Synaptic Transmission/physiology , Animals , Animals, Newborn , CX3C Chemokine Receptor 1 , Chemokine CX3CL1 , Chemokines, CX3C/immunology , Chemokines, CX3C/pharmacology , Dose-Response Relationship, Drug , Electric Stimulation/methods , Excitatory Postsynaptic Potentials/drug effects , Excitatory Postsynaptic Potentials/radiation effects , Hippocampus/cytology , Hippocampus/drug effects , Humans , In Vitro Techniques , Membrane Proteins/immunology , Membrane Proteins/pharmacology , Mice , Mice, Knockout , Neural Inhibition/drug effects , Neural Inhibition/physiology , Neural Inhibition/radiation effects , Patch-Clamp Techniques/methods , Receptors, Chemokine/deficiency , Synaptic Transmission/drug effects , Synaptic Transmission/radiation effects
14.
Mod Rheumatol ; 16(3): 124-30, 2006.
Article in English | MEDLINE | ID: mdl-16767549

ABSTRACT

Leukocyte adhesion and trafficking at the endothelium requires both adhesion molecules and chemotactic factors. Fractalkine (CX3C) is a unique chemokine, and is expressed on tumor necrosis factor-alpha- and interleukin-1-activated endothelial cells (ECs). Fractalkine receptor, CX3CR1, is expressed on NK cells, monocytes, and some portion of CD4- and CD8-positive T cells. Interactions between fractalkine and CX3CR1 can mediate not only chemotaxis, but also cell adhesion in the absence of substrates for other adhesion molecules. Furthermore, fractalkine activates NK cells, leading to increased cytotoxicity and interferon-gamma production. Recently, accumulating evidence has shown that fractalkine is involved in the pathogenesis of rheumatoid arthritis and allied conditions. This review examines new concepts underlying fractalkine-mediated leukocyte migration and tissue damage, focusing primarily on the pathophysiological roles of fractalkine in rheumatic diseases.


Subject(s)
Arthritis, Rheumatoid/physiopathology , Chemokines, CX3C/immunology , Chemokines/immunology , Chemotaxis, Leukocyte/physiology , Membrane Proteins/immunology , Receptors, Chemokine/immunology , Arthritis, Rheumatoid/immunology , CX3C Chemokine Receptor 1 , Chemokine CX3CL1 , Chemokines/physiology , Chemokines, CX3C/physiology , Humans , Inflammation Mediators/metabolism , Membrane Proteins/physiology , Receptors, Chemokine/metabolism
15.
Br J Haematol ; 133(5): 550-7, 2006 Jun.
Article in English | MEDLINE | ID: mdl-16681644

ABSTRACT

Fractalkine is a unique endothelial cell-derived chemokine that functions both as a chemoattractant and as an adhesion molecule. Recent findings suggest that fractalkine plays an important role in inflammatory diseases by modulating leucocyte endothelial cell interactions. A modulating effect on the immune system in severe sepsis has been suggested for recombinant human activated protein C (rhAPC). However, a little is known about the effect of rhAPC on the endothelial release of soluble fractalkine. The effect of rhAPC (50 ng/ml to 10 microg/ml) and protein C (in equimolar concentrations) on the synthesis of fraktalkine-mRNA and release of soluble protein in human umbilical vein endothelial cells (HUVEC) was determined by reverse transcription-polymerase chain reaction and by an enzyme-linked immunosorbent assay. rhAPC at supra-pharmacological concentrations (1-10 microg/ml) stimulated fractalkine-messenger RNA-gene transcription and release of soluble fractalkine in a time- and dose-dependent manner, whereas the zymogen protein C was ineffective. As shown by experiments using monoclonal antibodies against the thrombin receptor, protease-activated receptor-1 (PAR-1), PAR-2 and against the endothelial protein C receptor (EPCR), the effect of rhAPC on fractalkine upregulation was mediated by binding to the EPCR-receptor and signalling via PAR-1. These in vitro data demonstrate that induction of fractalkine release is an important response of HUVEC to stimulation with rhAPC and may lead to a better understanding of the molecular pathways involved in the mode of action of rhAPC. Further clinical trials are needed to confirm the in vivo relevance of these data.


Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/immunology , Chemokines, CX3C/immunology , Endothelial Cells/immunology , Membrane Proteins/immunology , Protein C/immunology , Antigens, CD/immunology , Cells, Cultured , Chemokine CX3CL1 , Dose-Response Relationship, Immunologic , Endothelial Protein C Receptor , Endothelium, Vascular/immunology , Enzyme Precursors/immunology , Humans , Microarray Analysis/methods , RNA, Messenger/biosynthesis , Receptor, PAR-1/immunology , Receptor, PAR-2/immunology , Receptors, Cell Surface/immunology , Recombinant Proteins/immunology , Solubility , Thrombin/immunology , Up-Regulation/immunology
16.
Eur J Immunol ; 36(4): 1019-27, 2006 Apr.
Article in English | MEDLINE | ID: mdl-16525992

ABSTRACT

Fractalkine (CX3CL1) is a unique membrane-bound CX3C chemokine that serves as a potent chemoattractant for lymphocytes. The hypothesis of this study is that dendritic cells (DC) genetically modified ex vivo to overexpress fractalkine would enhance the T cell-mediated cellular immune response with a consequent induction of anti-tumor immunity to suppress tumor growth. To prove this hypothesis, established tumors of different mouse cancer cells (B16-F10 melanoma, H-2b, and Colon-26 colon adenocarcinoma, H-2d) were treated with intratumoral injection of bone marrow-derived DC that had been modified in vitro with an RGD fiber-mutant adenovirus vector expressing mouse fractalkine (Ad-FKN). In both tumor models tested, treatment of tumor-bearing mice with Ad-FKN-transduced DC gave rise to a significant suppression of tumor growth along with survival advantages in the treated mice. Immunohistochemical analysis of tumors treated with direct injection of Ad-FKN-transduced DC demonstrated that the treatment prompted CD8+ T cells and CD4+ T cells to accumulate in the tumor milieu, leading to activation of immune-relevant processes. Consistent with the finding, the intratumoral administration of Ad-FKN-transduced DC evoked tumor-specific cytotoxic T lymphocytes, which ensued from in vivo priming of Th1 immune responses in the treated host. In addition, the anti-tumor effect provided by intratumoral injection of Ad-FKN-transduced DC was completely abrogated in CD4+ T cell-deficient mice as well as in CD8+ T cell-deficient mice. These results support the concept that genetic modification of DC with a recombinant fractalkine adenovirus vector may be a useful strategy for cancer immunotherapy protocols.


Subject(s)
Chemokines, CX3C/genetics , Dendritic Cells/immunology , Genetic Therapy , Membrane Proteins/genetics , Neoplasms, Experimental/immunology , Neoplasms, Experimental/therapy , Adenoviridae , Animals , Cell Line, Tumor , Chemokine CX3CL1 , Chemokines, CX3C/immunology , Enzyme-Linked Immunosorbent Assay , Female , Genetic Vectors , Immunohistochemistry , Immunotherapy , Membrane Proteins/immunology , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Neoplasms, Experimental/genetics , Reverse Transcriptase Polymerase Chain Reaction , T-Lymphocytes/immunology , Transduction, Genetic
17.
Oncol Rep ; 15(2): 485-8, 2006 Feb.
Article in English | MEDLINE | ID: mdl-16391873

ABSTRACT

Many chemokine receptors are typically found on natural killer cells, including CX3CR1, the receptor for the chemokine fractalkine (FKN). This study explored whether interaction between CX3CR1 and FKN is relevant for NK cell functions in cytotoxicity against tumors. FKN expression was examined by polymerase chain reaction and CX3CR1 expression in NK cells was analyzed by flow cytometry. NK cell cytotoxicity was examined by 4-h 51Cr-release assay. FKN was expressed in a variety of tumor cell lines such as K562 cells, an NK-sensitive cell line. Approximately 90% of peripheral blood NK cells and almost all of the NK cell line, NK-92 cells, expressed CX3CR1. Anti-CX3CR1 antibody strongly neutralized the cytotoxicity of NK cells against K562 cells, and pretreatment of NK cells with recombinant soluble FKN improved the cytolytic function on tumor cells. This study demonstrates that an interaction between CX3CR1 on NK cells and FKN on tumor cells is involved in the natural cytotoxicity of NK cells against tumors.


Subject(s)
Chemokines, CX3C/metabolism , Cytotoxicity, Immunologic , Killer Cells, Natural/immunology , Membrane Proteins/metabolism , Neoplasms/immunology , Receptors, Chemokine/metabolism , CX3C Chemokine Receptor 1 , Cell Line, Tumor , Chemokine CX3CL1 , Chemokines, CX3C/immunology , Flow Cytometry , Humans , Membrane Proteins/immunology , Receptors, Chemokine/immunology , Reverse Transcriptase Polymerase Chain Reaction
18.
Medicina (B.Aires) ; 66(supl.2): 16-21, 2006. tab, ilus
Article in Spanish | BINACIS | ID: bin-123541

ABSTRACT

The central role of the immune system is the preservation of the health against several pathogenic microbes and injury agents. However, on special conditions defensive mechanisms triggered towards the foreign agent can damage the host. Clinical and experimental evidence indicate that inflammatory reaction triggered by the main components of Shiga toxin (Stx)-producing Escherichia coil (STEC), participate in the evolution to the complete form of HUS. When children are diagnosed of HUS, they present evidence that have suffered a very strong and early inflammatory response. These features include: the presence of a marked neutrophilia, the polymorfonuclear leucocytes (PMN) are "deactivated or exhausted" and the monocytes are differentiated towards an inflammatory phenotype (CD14-reduced and CD16-enhanced membrane expression). In addition, HUS-patients show a marked reduction in the absolute and relative number of leucocytes carrying the receptor (CX3CR1) for the chemokine "Fractalkine" (FKN, CX3CL1), which are the classic monocytes and Natural Killer cells (NK). All these cells express a high cytotoxic potencial. The chemokine FKN is expressed in endothelial and epithelial renal cells, and is involved in the pathogenic mechanism of different nephropathies. Noteworthy, we found a significant correlation between the severity of the renal damage (as days of anuria) and the alterations described above. Finally, the protective role of specific immune response, mainly through the antibody production with Stx-neutralizing capacity, is discussed.(AU)


Subject(s)
Humans , Animals , Rats , Hemolytic-Uremic Syndrome/immunology , Immunity, Innate/immunology , Shiga Toxin/toxicity , Neutrophil Activation/immunology , Antigens, CD/immunology , Chemokines, CX3C/immunology , Escherichia coli/immunology , Escherichia coli/pathogenicity , Escherichia coli Infections/immunology , Fibroblast Growth Factors/immunology , Hemolytic-Uremic Syndrome/therapy , Killer Cells, Natural/immunology , Murinae , Neutrophils/immunology , Renal Dialysis , Shiga Toxin/antagonists & inhibitors , Shiga Toxin/immunology , Cytokines/immunology , Disease Models, Animal
19.
Eur J Immunol ; 35(5): 1371-80, 2005 May.
Article in English | MEDLINE | ID: mdl-15789339

ABSTRACT

The CX3C chemokine fractalkine (CX3CL1) exists as both a membrane-bound form promoting firm cell-cell adhesion and a soluble form chemoattracting leukocytes expressing its receptor CX3CR1. When adenoviral vector expressing mouse fractalkine (AdFKN) was transduced to the tumor cells, fractalkine was expressed as both membrane-bound form on the tumor cells and soluble form in the supernatant in vitro. Intratumoral injection of AdFKN (1 x 10(9)PFU/tumor) into C26 and B16F10 tumors resulted in marked reduction of tumor growth compared to control (C26: 86.5%, p<0.001; B16F10: 85.5%, p<0.001). Histological examination of tumor tissues revealed abundant infiltration of NK cells, dendritic cells, and CD8(+) T lymphocytes 3 and/or 6 days after treatment with AdFKN. Splenocytes from mice treated by AdFKN developed tumor-specific cytotoxic T cells, and thereby protected from rechallenging with parental tumor cells. Antitumor effects by AdFKN were completely abrogated in both NK cell-depleted mice and CD8(-/-) mice, and partially blocked in CD4(-/-) mice. These data indicated that fractalkine mediates antitumor effects by both NK cell-dependent and T cell-dependent mechanisms. This study suggests that fractalkine can be a suitable candidate for immunogene therapy of cancer because fractalkine induces both innate and adaptive immunity.


Subject(s)
Chemokines, CX3C/immunology , Genetic Therapy , Killer Cells, Natural/immunology , Lymphocyte Subsets/immunology , Membrane Proteins/immunology , Neoplasms/immunology , T-Lymphocytes/immunology , Animals , Blotting, Western , Cell Line, Tumor , Chemokine CX3CL1 , Chemokines, CX3C/genetics , Flow Cytometry , Membrane Proteins/genetics , Mice , Reverse Transcriptase Polymerase Chain Reaction , Transduction, Genetic
20.
J Infect Dis ; 190(11): 1936-40, 2004 Dec 01.
Article in English | MEDLINE | ID: mdl-15529257

ABSTRACT

Respiratory syncytial virus (RSV) is an important cause of severe lower respiratory tract illness in infants and the elderly. Presently, no safe and efficacious RSV vaccine exists; however, advances in our understanding of immunity and the pathogenesis of disease associated with RSV infection may lead to new vaccine strategies. RSV G protein contains a CX3C chemokine motif that interacts with the CX3CR1 chemokine receptor and modifies the activities of fractalkine. In the present study, we show that anti-RSV G protein antibody responses after recent RSV infection or vaccination are associated with inhibition of RSV G protein CX3C-CX3CR1 interaction and RSV G protein-mediated leukocyte chemotaxis.


Subject(s)
Antibodies, Viral/biosynthesis , Chemokines, CX3C/immunology , Membrane Proteins/immunology , Receptors, Chemokine/immunology , Respiratory Syncytial Virus Infections/immunology , Respiratory Syncytial Virus Vaccines/immunology , Respiratory Syncytial Virus, Human/immunology , Viral Proteins/immunology , Adult , Antibodies, Viral/analysis , Binding Sites, Antibody , CX3C Chemokine Receptor 1 , Chemokine CX3CL1 , Chemokines, CX3C/chemistry , Chemotaxis, Leukocyte , Child, Preschool , Humans , Infant , Leukocytes/immunology , Respiratory Syncytial Virus Infections/prevention & control , Respiratory Syncytial Virus Infections/virology , Respiratory Syncytial Virus Vaccines/administration & dosage , Vaccination , Vaccines, Attenuated/administration & dosage , Vaccines, Attenuated/immunology , Viral Proteins/antagonists & inhibitors , Viral Proteins/chemistry
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