RESUMEN
Dendritic cells (DCs) form a network comprising different populations that initiate and differentially regulate immune responses. Langerhans cells (LCs) represent a unique population of DCs colonizing epithelium, and we present here observations suggesting that macrophage inflammatory protein (MIP)-3alpha plays a central role in LC precursor recruitment into the epithelium during inflammation. (a) Among DC populations, MIP-3alpha was the most potent chemokine inducing the selective migration of in vitro-generated CD34(+) hematopoietic progenitor cell-derived LC precursors and skin LCs in accordance with the restricted MIP-3alpha receptor (CC chemokine receptor 6) expression to these cells. (b) MIP-3alpha was mainly produced by epithelial cells, and the migration of LC precursors induced by the supernatant of activated skin keratinocytes was completely blocked with an antibody against MIP-3alpha. (c) In vivo, MIP-3alpha was selectively produced at sites of inflammation as illustrated in tonsils and lesional psoriatic skin where MIP-3alpha upregulation appeared associated with an increase in LC turnover. (d) Finally, the secretion of MIP-3alpha was strongly upregulated by cells of epithelial origin after inflammatory stimuli (interleukin 1beta plus tumor necrosis factor alpha) or T cell signals. Results of this study suggest a major role of MIP-3alpha in epithelial colonization by LCs under inflammatory conditions and immune disorders, and might open new ways to control epithelial immunity.
Asunto(s)
Quimiocinas CC , Inflamación/metabolismo , Células de Langerhans/fisiología , Proteínas Inflamatorias de Macrófagos/fisiología , Células Madre/fisiología , Animales , Línea Celular , Quimiocina CCL20 , Epitelio/química , Humanos , Proteínas Inflamatorias de Macrófagos/análisis , Ratones , Ratones Endogámicos BALB C , Psoriasis/metabolismo , Receptores CCR6 , Receptores de Quimiocina/análisis , Linfocitos T/fisiologíaRESUMEN
Analysis of the cDNA encoding murine interleukin (IL) 17 (cytotoxic T lymphocyte associated antigen 8) predicted a secreted protein sharing 57% amino acid identity with the protein predicted from ORF13, an open reading frame of Herpesvirus saimiri. Here we report on the cloning of human IL-17 (hIL-17), the human counterpart of murine IL-17. hIL-17 is a glycoprotein of 155 amino acids secreted as an homodimer by activated memory CD4+ T cells. Although devoid of direct effects on cells of hematopoietic origin, hIL-17 and the product of its viral counterpart, ORF13, stimulate epithelial, endothelial, and fibroblastic cells to secrete cytokines such as IL-6, IL-8, and granulocyte-colony-stimulating factor, as well as prostaglandin E2. Furthermore, when cultured in the presence of hIL-17, fibroblasts could sustain the proliferation of CD34+ hematopoietic progenitors and their preferential maturation into neutrophils. These observations suggest that hIL-17 may constitute (a) an early initiator of the T cell-dependent inflammmatory reaction; and (b) an element of the cytokine network that bridges the immune system to hematopoiesis.
Asunto(s)
Citocinas/biosíntesis , Endotelio Vascular/inmunología , Células Madre Hematopoyéticas/inmunología , Interleucinas/biosíntesis , Linfocitos T/inmunología , Secuencia de Aminoácidos , Animales , Artritis Reumatoide/inmunología , Secuencia de Bases , Dinoprostona/biosíntesis , Endotelio Vascular/efectos de los fármacos , Fibroblastos/inmunología , Factor Estimulante de Colonias de Granulocitos/biosíntesis , Hematopoyesis , Células Madre Hematopoyéticas/efectos de los fármacos , Herpesvirus Saimiriino 2/genética , Herpesvirus Saimiriino 2/metabolismo , Humanos , Inflamación , Interferón gamma/farmacología , Interleucina-17 , Interleucina-6/biosíntesis , Interleucina-8/biosíntesis , Interleucinas/química , Interleucinas/inmunología , Linfocitos/inmunología , Sustancias Macromoleculares , Ratones , Datos de Secuencia Molecular , Sistemas de Lectura Abierta , Proteínas Recombinantes/biosíntesis , Valores de Referencia , Homología de Secuencia de Aminoácido , Piel/inmunología , Células del Estroma/efectos de los fármacos , Células del Estroma/inmunología , Membrana Sinovial/inmunología , Transfección , Factor de Necrosis Tumoral alfa/farmacología , Proteínas Virales/biosíntesis , Proteínas Virales/químicaRESUMEN
Using a panel of monoclonal antibodies (MAbs) previously characterized by seroneutralization, immunofluorescence and radioimmunoprecipitation, we have identified Pestivirus proteins useful for diagnostic purposes from the cytopathic Osloss isolate of bovine viral diarrhea virus (BVDV). Proteins that should be useful for vaccination have also been analysed. Cell-free translation of RNA from glycoprotein-coding cDNA fragments produced, when synthesized in the presence of canine pancreatic microsomes, two glycosylated proteins that were independently recognized and immunoprecipitated by two distinct classes of neutralizing MAbs. A similar in vitro procedure was carried out on nonstructural protein-coding sequences and allowed to identify a viral translation product that specifically reacted with MAbs directed against the 80 kDA protein of a number of Pestivirus strains. Its positioning within the polyprotein encoded by the viral genome was refined by epitope scanning using synthetic hexameric peptides. This viral antigen was further expressed in E. coli, produced as inclusion bodies and used successfully as an ELISA antigen in both competitive and indirect assays for the detection of BVD antibodies in cattle sera.
Asunto(s)
Diarrea Mucosa Bovina Viral/diagnóstico , Virus de la Diarrea Viral Bovina/inmunología , Proteínas Virales/análisis , Vacunas Virales/inmunología , Animales , Anticuerpos Monoclonales/inmunología , Anticuerpos Antivirales/análisis , Diarrea Mucosa Bovina Viral/prevención & control , Bovinos , Perros , Ensayo de Inmunoadsorción Enzimática , Vacunación , Proteínas no Estructurales Virales/análisis , Proteínas Virales/inmunologíaRESUMEN
TGF-beta1 released from dentin degraded by bacterial or iatrogenic agents is suspected to influence dental pulp response, including the modulation of cell migration. To determine the consequences of TGF-beta1 action on pulp immune cells, we analyzed, by immunohistochemistry, the effect of transdentinally diffusing TGF-beta1 on their localization in a human tooth slice culture model. TGF-beta1 induced an accumulation of HLA-DR-positive cells in both odontoblast and subodontoblast layers of the stimulated zone. Together with HLA-DR, these cells co-expressed Factor XIIIa and CD68, two features of immature antigen-presenting dendritic cells (DC), as well as the TGF-beta1 specific receptor TbetaRII. In contrast, no effect could be detected on the localization of either mature DC-LAMP-positive DC or of T- and B-lymphocytes. Analysis of these data suggests that TGF-beta1 released from dentin degraded by bacterial or iatrogenic agents could be involved in the immune response of the dental pulp resulting from tooth injury.
Asunto(s)
Células Dendríticas/efectos de los fármacos , Odontoblastos/efectos de los fármacos , Factor de Crecimiento Transformador beta/farmacología , Adolescente , Células Presentadoras de Antígenos/efectos de los fármacos , Antígenos CD/análisis , Antígenos de Diferenciación Mielomonocítica/análisis , Linfocitos B/efectos de los fármacos , Recuento de Células , Movimiento Celular/efectos de los fármacos , Técnicas de Cultivo , Pulpa Dental/citología , Pulpa Dental/efectos de los fármacos , Factor XIIIa/análisis , Antígenos HLA-DR/análisis , Humanos , Proteínas de Membrana de los Lisosomas , Receptores de Factores de Crecimiento Transformadores beta/análisis , Linfocitos T/efectos de los fármacos , Factor de Crecimiento Transformador beta1RESUMEN
A panel of monoclonal antibodies was prepared by immunization of BALB/c mice with Moredun (BD) virus strains. These antibodies were characterized by immunofluorescence and seroneutralization against BD, BVD and hog cholera (HC) virus strains, and radioimmunoprecipitation of BVD-infected cells extracts. The MAbs reacting with the majority of the Pestivirus strains recognize the 80 kDa antigen of the BVD cytophathic strains. The 80 kDa antigen of the BVD/Osloss virus strain has been cloned and expressed in E. coli as a fusion protein with beta-galactosidase. The fusion protein has been purified from inclusion bodies and used successfully as an antigen for ELISA detection of BVDV specific antibodies in bovine sera. A competitive ELISA using MAbs is more specific than a direct assay. These results compare well with the ones obtained with antigen extracted from BVDV-infected cells.
Asunto(s)
Anticuerpos Monoclonales/inmunología , Anticuerpos Antivirales/análisis , Antígenos Virales/inmunología , Virus de la Diarrea Viral Bovina/inmunología , Pestivirus/inmunología , Animales , Especificidad de Anticuerpos , Unión Competitiva , Bovinos , Ensayo de Inmunoadsorción Enzimática , Técnica del Anticuerpo Fluorescente , Hibridomas , Ratones , Ratones Endogámicos BALB C , Pruebas de Neutralización , Ensayo de Radioinmunoprecipitación , Proteínas Recombinantes/inmunologíaRESUMEN
Rheumatoid synovitis is characterized by an infiltration of mononuclear cells and by the proliferation of synoviocytes. Monocytes and synoviocytes are major producers of cytokines, growth factors, and enzymes that contribute to the rheumatoid arthritis (RA) process. Since they are in close contact in vivo, we engaged in an in vitro study of the functional consequences of their interactions. Coculture of unstimulated elutriated normal blood monocytes over RA synoviocytes resulted in a synergistic increase of the production of IL-6, granulocyte-macrophage colony-stimulating factor (GM-CSF), leukemia inhibitory factor (LIF), and IL-8, when compared with their respective production in culture alone. In contrast, cytokines such as IL-10, IL-1 beta, IL-1 alpha, and TNF-alpha could not be detected. The IL-6 production in coculture was further increased by the addition of IL-1 beta, GM-CSF, IFN-gamma, or TNF-alpha, but was inhibited by the addition of IL-10, IL-4, IL-13, or IL-1Ra, an effect reverted by the addition of IL-1 beta. Moreover, an inhibition was also observed with anti-CD14 mAb and newly raised mAbs directed against RA synoviocytes. Under reducing conditions, the mAb SY12 precipitated a 150-kDa surface membrane protein, identified as amino-peptidase N (CD13/AP-N). Collectively, these results indicate that 1) monocytes and synoviocytes interact with each other to produce proinflammatory cytokines, 2) pro- and antiinflammatory cytokines have opposite effects on IL-6 production, and 3) molecules such as IL-1, CD14, and CD13 are involved.
Asunto(s)
Artritis Reumatoide/inmunología , Antígenos CD13/farmacología , Interleucina-1/farmacología , Interleucina-6/biosíntesis , Receptores de Lipopolisacáridos/farmacología , Monocitos/inmunología , Membrana Sinovial/inmunología , Agregación Celular , Fibroblastos/citología , Fibroblastos/inmunología , Humanos , Monocitos/citología , Membrana Sinovial/citologíaRESUMEN
We analyzed herein whether antibodies to HLA class I alpha1 domain, which trigger apoptosis of activated T cells, may also control the growth/survival of human B lymphocytes. Addition of monoclonal antibody (MoAb) 90 (mouse IgG1) or YTH862 (rat IgG2b) was found to strongly inhibit the proliferation of CD40-activated total tonsil B cells as well as that of purified naive, germinal center, and memory B-cell subsets. This inhibitory effect was not prevented by addition of B-cell tropic factors, such as interleukin-2 (IL-2), IL-4, and IL-10, and was a result of induced B-cell apoptosis as shown by using a TUNEL assay and DNA electrophoresis. In contrast, engagement of another epitope of the alpha1 domain, as well as that of the alpha2 and alpha3 domains by specific anti-HLA class I MoAbs, failed to inhibit DNA synthesis and to induce apoptosis of CD40-activated B cells. As recently reported for acquisition of sensitivity to Fas (APO-1/CD95) -dependent apoptosis, susceptibility to MoAb90-and YTH862-induced death was restricted to CD40-activated B cells, because resting and anti-IgM-activated B cells did not undergo apoptosis after HLA class I engagement. Moreover, ligation of the B-cell receptor protected CD40-activated B cells from both HLA class I- and Fas-mediated growth inhibition and apoptosis. Taken together, these results show that engagement of the alpha1 domain of HLA class I induces apoptotic cell death of CD40-activated, but not of antigen-activated B cells, and would, therefore, suggest a possible role for HLA class I molecules in the control of B-cell homeostasis.
Asunto(s)
Anticuerpos Monoclonales/farmacología , Apoptosis/inmunología , Linfocitos B/inmunología , Antígenos CD40/fisiología , Antígenos de Histocompatibilidad Clase I/inmunología , Activación de Linfocitos , Animales , Apoptosis/efectos de los fármacos , Subgrupos de Linfocitos B/citología , Subgrupos de Linfocitos B/inmunología , Linfocitos B/citología , Linfocitos B/fisiología , Células Cultivadas , Humanos , Inmunoglobulina G , Células L , Ratones , Tonsila Palatina/inmunología , Ratas , Transfección , Receptor fas/biosíntesisRESUMEN
BACKGROUND: Bet v 1 and homologous proteins represent major allergens for almost 95% of patients allergic to tree pollen and approximately 70% of those allergic to fruits and vegetables. As yet, no continuous (sequential) IgE epitopes have been determined for Bet v 1, and evidence has accumulated that Bet v 1 IgE epitopes belong to the conformational (discontinuous) type. OBJECTIVE: A panel of 85 mouse monoclonal anti-Bet v 1 antibodies was raised as a tool with which to study the interaction of human IgE antibodies with Bet v 1. METHODS: The epitopes of selected monoclonal antibodies (mAbs) were characterized by mapping with synthetic overlapping peptides and by cross-competition experiments. Cross-reactivity of Bet v 1-specific mAbs with tree and plant food allergens was investigated by Western blotting. The influence of Bet v 1-specific mAbs on the IgE-Bet v 1 interaction was studied by competition assays with immobilized purified recombinant Bet v 1 and by basophil histamine release experiments. RESULTS: Antibodies that increased the IgE binding to Bet v 1 up to fivefold could be defined, whereas others inhibited IgE binding to Bet v 1 up to 99% and competed with the Bet v 1-induced histamine release from patients' basophils. CONCLUSION: The activity of the enhancing antibodies is interpreted as a stabilization of Bet v 1 states/IgE epitopes, which are either more accessible for certain IgE antibodies or are recognized with higher affinity. Those mAbs that competed with the Bet v 1-IgE interaction, if humanized or produced as recombinant antibody fragments, might be considered as potential tools for local allergy therapy.
Asunto(s)
Alérgenos , Anticuerpos Monoclonales/biosíntesis , Anticuerpos Monoclonales/inmunología , Reacciones Antígeno-Anticuerpo , Epítopos/análisis , Inmunoglobulina E/inmunología , Proteínas de Plantas/inmunología , Animales , Anticuerpos Bloqueadores/inmunología , Anticuerpos Monoclonales/aislamiento & purificación , Antígenos de Plantas , Basófilos/inmunología , Basófilos/metabolismo , Western Blotting , Cromatografía de Afinidad , Reacciones Cruzadas/inmunología , Ensayo de Inmunoadsorción Enzimática , Liberación de Histamina , Humanos , Ratones , Ratones Endogámicos BALB C , Mapeo Peptídico , Proteínas de Plantas/genética , Pruebas de Precipitina , Proteínas Recombinantes/inmunologíaRESUMEN
In this study, we describe human FDF03, a novel member of the Ig superfamily expressed as a monomeric 44-kDa transmembrane glycoprotein and containing a single extracellular V-set Ig-like domain. Two potential secreted isoforms were also identified. The gene encoding FDF03 mapped to chromosome 7q22. FDF03 was mostly detected in hemopoietic tissues and was expressed by monocytes, macrophages, and granulocytes, but not by lymphocytes (B, T, and NK cells), indicating an expression restricted to cells of the myelomonocytic lineage. FDF03 was also strongly expressed by monocyte-derived dendritic cells (DC) and preferentially by CD14+/CD1a- DC derived from CD34+ progenitors. Moreover, flow cytometric analysis showed FDF03 expression by CD11c+ blood and tonsil DC, but not by CD11c- DC precursors. The FDF03 cytoplasmic tail contained two immunoreceptor tyrosine-based inhibitory motif (ITIM)-like sequences. When overexpressed in pervanadate-treated U937 cells, FDF03 was tyrosine-phosphorylated and recruited Src homology-2 (SH2) domain-containing protein tyrosine phosphatase (SHP)-2 and to a lesser extent SHP-1. Like engagement of the ITIM-bearing receptor LAIR-1/p40, cross-linking of FDF03 inhibited calcium mobilization in response to CD32/FcgammaRII aggregation in transfected U937 cells, thus demonstrating that FDF03 can function as an inhibitory receptor. However, in contrast to LAIR-1/p40, cross-linking of FDF03 did not inhibit GM-CSF-induced monocyte differentiation into DC. Thus, FDF03 is a novel ITIM-bearing receptor selectively expressed by cells of myeloid origin, including DC, that may regulate functions other than that of the broadly distributed LAIR-1/p40 molecule.
Asunto(s)
Células Dendríticas/metabolismo , Granulocitos/metabolismo , Inmunoglobulinas/química , Glicoproteínas de Membrana/biosíntesis , Monocitos/metabolismo , Receptores Inmunológicos/biosíntesis , Homología de Secuencia de Aminoácido , Adulto , Empalme Alternativo , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Señalización del Calcio/inmunología , Diferenciación Celular/inmunología , Células Cultivadas , Cromosomas Humanos Par 7 , Clonación Molecular , ADN Complementario/aislamiento & purificación , Células Dendríticas/inmunología , Granulocitos/inmunología , Humanos , Inmunoglobulinas/genética , Integrina alfaXbeta2/biosíntesis , Péptidos y Proteínas de Señalización Intracelular , Receptores de Lipopolisacáridos/biosíntesis , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/inmunología , Glicoproteínas de Membrana/metabolismo , Ratones , Datos de Secuencia Molecular , Monocitos/citología , Monocitos/inmunología , Familia de Multigenes/inmunología , Especificidad de Órganos/genética , Especificidad de Órganos/inmunología , Fosforilación , Proteína Tirosina Fosfatasa no Receptora Tipo 11 , Proteína Tirosina Fosfatasa no Receptora Tipo 6 , Proteínas Tirosina Fosfatasas/metabolismo , ARN Mensajero/biosíntesis , Receptores de IgG/antagonistas & inhibidores , Receptores de IgG/fisiología , Receptores Inmunológicos/genética , Receptores Inmunológicos/inmunología , Receptores Inmunológicos/metabolismo , Proteínas Tirosina Fosfatasas con Dominio SH2 , Solubilidad , Células U937 , Dominios Homologos src/inmunologíaRESUMEN
In a search for genes expressed by dendritic cells (DC), we have cloned cDNAs encoding different forms of an asialoglycoprotein receptor (ASGPR). The DC-ASGPR represents long and short isoforms of human macrophage lectin, a Ca(2+)-dependent type II transmembrane lectin displaying considerable homology with the H1 and H2 subunits of the hepatic ASGPR. Immunoprecipitation from DC using an anti-DC-ASGPR mAb yielded a major 40-kDa protein with an isoelectric point of 8.2. DC-ASGPR mRNA was observed predominantly in immune tissues. Both isoforms were detected in DC and granulocytes, but not in T, B, or NK cells, or monocytes. DC-ASGPR species were restricted to the CD14-derived DC obtained from CD34(+) progenitors, while absent from the CD1a-derived subset. Accordingly, both monocyte-derived DC and tonsillar interstitial-type DC expressed DC-ASGPR protein, while Langerhans-type cells did not. Furthermore, DC-ASGPR is a feature of immaturity, as expression was lost upon CD40 activation. In agreement with the presence of tyrosine-based and dileucine motifs in the intracytoplasmic domain, mAb against DC-ASGPR was rapidly internalized by DC at 37 degrees C. Finally, intracellular DC-ASGPR was localized to early endosomes, suggesting that the receptor recycles to the cell surface following internalization of ligand. Our findings identify DC-ASGPR/human macrophage lectin as a feature of immature DC, and as another lectin important for the specialized Ag-capture function of DC.
Asunto(s)
Células Dendríticas/inmunología , Endocitosis , Lectinas Tipo C , Receptores de Superficie Celular/biosíntesis , Receptores de Superficie Celular/fisiología , Secuencia de Aminoácidos , Animales , Receptor de Asialoglicoproteína , Antígenos CD40/metabolismo , Células Cultivadas , Clonación Molecular , Endosomas/química , Granulocitos/inmunología , Humanos , Lectinas/genética , Proteínas de la Membrana/genética , Ratones , Datos de Secuencia Molecular , Monocitos/inmunología , Filogenia , ARN Mensajero/biosíntesis , Ratas , Receptores de Superficie Celular/genética , Homología de Secuencia de Aminoácido , Células Madre/inmunologíaRESUMEN
We have identified a novel lysosome-associated membrane glycoprotein localized on chromosome 3q26.3-q27, DC-LAMP, which is homologous to CD68. DC-LAMP mRNA is present only in lymphoid organs and DC. A specific MAb detects the protein exclusively in interdigitating dendritic cells. Expression of DC-LAMP increases progressively during in vitro DC differentiation, but sharply upon activation with LPS, TNFalpha, or CD40L. Confocal microscopy confirmed the lysosomal distribution of the protein. Furthermore, DC-LAMP was found in the MHC class II compartment immediately before the translocation of MHC class II molecules to the cell surface, after which it concentrates into perinuclear lysosomes. This suggests that DC-LAMP might change the lysosome function after the transfer of peptide-MHC class II molecules to the surface of DC.
Asunto(s)
Antígenos CD/biosíntesis , Células Dendríticas/citología , Células Dendríticas/metabolismo , Antígenos de Histocompatibilidad Clase II/metabolismo , Glicoproteínas de Membrana/biosíntesis , Secuencia de Aminoácidos , Anticuerpos Monoclonales/análisis , Antígenos CD/genética , Antígenos CD/inmunología , Secuencia de Bases , Diferenciación Celular/fisiología , División Celular/fisiología , ADN Complementario/análisis , Células Dendríticas/inmunología , Antígenos de Histocompatibilidad Clase II/química , Humanos , Inmunohistoquímica , Linfa/citología , Proteínas de Membrana de los Lisosomas , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/inmunología , Datos de Secuencia Molecular , ARN Mensajero/biosíntesisRESUMEN
We generated monoclonal antibody (mAb) DCGM4 by immunization with human dendritic cells (DC) from CD34+ progenitors cultured with granulocyte-macrophage colony-stimulating factor and TNF-alpha. mAb DCGM4 was selected for its reactivity with a cell surface epitope present only on a subset of DC. Reactivity was strongly enhanced by the Langerhans cell (LC) differentiation factor TGF-beta and down-regulated by CD40 ligation. mAb DCGM4 selectively stained LC, hence we propose that the antigen be termed Langerin. mAb DCGM4 also stained intracytoplasmically, but neither colocalized with MHC class II nor with lysosomal LAMP-1 markers. Notably, mAb DCGM4 was rapidly internalized at 37 degrees C, but did not gain access to MHC class II compartments. Finally, Langerin was immunoprecipitated as a 40-kDa protein with a pI of 5.2 - 5.5. mAb DCGM4 will be useful to further characterize Langerin, an LC-restricted molecule involved in routing of cell surface material in immature DC.
Asunto(s)
Anticuerpos Monoclonales/metabolismo , Antígenos de Superficie/inmunología , Células de Langerhans/química , Lectinas Tipo C , Lectinas de Unión a Manosa , Glicoproteínas de Membrana/inmunología , Reacciones Antígeno-Anticuerpo , Antígenos CD , Antígenos de Superficie/biosíntesis , Antígenos de Superficie/aislamiento & purificación , Antígenos de Superficie/fisiología , Antígenos CD40/metabolismo , Ligando de CD40 , Separación Celular , Regulación hacia Abajo/inmunología , Humanos , Células de Langerhans/metabolismo , Células de Langerhans/ultraestructura , Ligandos , Glicoproteínas de Membrana/biosíntesis , Glicoproteínas de Membrana/aislamiento & purificación , Glicoproteínas de Membrana/metabolismo , Glicoproteínas de Membrana/fisiología , Peso MolecularRESUMEN
We have identified a novel member of the calcium-dependent (C-type) lectin family. This molecule, designated DCIR (for dendritic cell (DC) immunoreceptor), is a type II membrane glycoprotein of 237 aa with a single carbohydrate recognition domain (CRD), closest in homology to those of the macrophage lectin and hepatic asialoglycoprotein receptors. The intracellular domain of DCIR contains a consensus immunoreceptor tyrosine-based inhibitory motif. A mouse cDNA, encoding a homologous protein has been identified. Northern blot analysis showed DCIR mRNA to be predominantly transcribed in hematopoietic tissues. The gene encoding human DCIR was localized to chromosome 12p13, in a region close to the NK gene complex. Unlike members of this complex, DCIR displays a typical lectin CRD rather than an NK cell type extracellular domain, and was expressed on DC, monocytes, macrophages, B lymphocytes, and granulocytes, but not detected on NK and T cells. DCIR was strongly expressed by DC derived from blood monocytes cultured with GM-CSF and IL-4. DCIR was mostly expressed by monocyte-related rather than Langerhans cell related DC obtained from CD34+ progenitor cells. Finally, DCIR expression was down-regulated by signals inducing DC maturation such as CD40 ligand, LPS, or TNF-alpha. Thus, DCIR is differentially expressed on DC depending on their origin and stage of maturation/activation. DCIR represents a novel surface molecule expressed by Ag presenting cells, and of potential importance in regulation of DC function.
Asunto(s)
Células Dendríticas/metabolismo , Lectinas Tipo C , Glicoproteínas de Membrana/biosíntesis , Fragmentos de Péptidos/biosíntesis , Receptores Inmunológicos , Receptores Mitogénicos/biosíntesis , Secuencia de Aminoácidos , Animales , Linfocitos B/metabolismo , Secuencia de Bases , Diferenciación Celular/genética , Diferenciación Celular/inmunología , Células Cultivadas , Cromosomas Humanos Par 12 , Clonación Molecular , ADN Complementario/aislamiento & purificación , Células Dendríticas/citología , Células Dendríticas/inmunología , Dosificación de Gen , Células Madre Hematopoyéticas/metabolismo , Humanos , Líquido Intracelular/metabolismo , Hígado/metabolismo , Tejido Linfoide/metabolismo , Macrófagos/inmunología , Macrófagos/metabolismo , Glicoproteínas de Membrana/química , Glicoproteínas de Membrana/genética , Ratones , Datos de Secuencia Molecular , Familia de Multigenes/inmunología , Especificidad de Órganos/genética , Fragmentos de Péptidos/química , Fragmentos de Péptidos/genética , Receptores Mitogénicos/química , Receptores Mitogénicos/genética , Homología de Secuencia de Aminoácido , Tirosina/metabolismoRESUMEN
Autoimmunity plays a key role in the immunopathogenesis of psoriasis; however, little is known about the recruitment of pathogenic cells to skin lesions. We report here that the CC chemokine, macrophage inflammatory protein-3 alpha, recently renamed CCL20, and its receptor CCR6 are markedly up-regulated in psoriasis. CCL20-expressing keratinocytes colocalize with skin-infiltrating T cells in lesional psoriatic skin. PBMCs derived from psoriatic patients show significantly increased CCR6 mRNA levels. Moreover, skin-homing CLA+ memory T cells express high levels of surface CCR6. Furthermore, the expression of CCR6 mRNA is 100- to 1000-fold higher on sorted CLA+ memory T cells than other chemokine receptors, including CXCR1, CXCR2, CXCR3, CCR2, CCR3, and CCR5. In vitro, CCL20 attracted skin-homing CLA+ T cells of both normal and psoriatic donors; however, psoriatic lymphocytes responded to lower concentrations of chemokine and showed higher chemotactic responses. Using ELISA as well as real-time quantitative PCR, we show that cultured primary keratinocytes, dermal fibroblasts, and dermal microvascular endothelial and dendritic cells are major sources of CCL20, and that the expression of this chemokine can be induced by proinflammatory mediators such as TNF-alpha/IL-1 beta, CD40 ligand, IFN-gamma, or IL-17. Taken together, these findings strongly suggest that CCL20/CCR6 may play a role in the recruitment of T cells to lesional psoriatic skin.