RESUMO
IL-9 has lent its numerical designation to the Th9 subset of CD4+ Th cells, although it is also produced by additional cell types, including mast cells. It is a pleiotropic cytokine involved in allergic reactions, parasitic infections, autoimmune inflammation, and cancer immunity. In this article, we provide evidence that NFATc2 has contradictory functions in the expression of IL-9 in murine Th9 cells and bone marrow-derived mast cells (BMMC). The basis for this is our observation that the production of IL-9 in NFATc2-deficient Th9 cells is increased, whereas it is decreased in BMMC devoid of NFATc2. In addition, NFATc2 deficiency almost completely abrogates the expression of IL-3 in both cell types. However, selectively in BMMC, the production of IL-9 critically depends on autocrine IL-3 acting via the sustained activation of STAT5 on the expression of IL-9. Furthermore, we demonstrate that IL-3 acts independently and synergistically with IL-1ß on the production of IL-9. Taken together, we highlight NFATc2-driven production of autocrine IL-3 as a critical and cell type-specific component for IL-9 expression in BMMC.
Assuntos
Interleucina-3/metabolismo , Interleucina-9/metabolismo , Mastócitos/imunologia , Fatores de Transcrição NFATC/metabolismo , Linfócitos T Auxiliares-Indutores/imunologia , Animais , Comunicação Autócrina , Células Cultivadas , Retroalimentação Fisiológica , Interleucina-9/genética , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fatores de Transcrição NFATC/genética , Fator de Transcrição STAT5/metabolismo , Regulação para CimaRESUMO
Immunological functions of mast cells remain poorly understood. Studies in Kit mutant mice suggest key roles for mast cells in certain antibody- and T cell-mediated autoimmune diseases. However, Kit mutations affect multiple cell types of both immune and nonimmune origin. Here, we show that targeted insertion of Cre-recombinase into the mast cell carboxypeptidase A3 locus deleted mast cells in connective and mucosal tissues by a genotoxic Trp53-dependent mechanism. Cre-mediated mast cell eradication (Cre-Master) mice had, with the exception of a lack of mast cells and reduced basophils, a normal immune system. Cre-Master mice were refractory to IgE-mediated anaphylaxis, and this defect was rescued by mast cell reconstitution. This mast cell-deficient strain was fully susceptible to antibody-induced autoimmune arthritis and to experimental autoimmune encephalomyelitis. Differences comparing Kit mutant mast cell deficiency models to selectively mast cell-deficient mice call for a systematic re-evaluation of immunological functions of mast cells beyond allergy.
Assuntos
Autoanticorpos/imunologia , Autoimunidade/imunologia , Integrases/metabolismo , Mastócitos/imunologia , Linfócitos T/imunologia , Anafilaxia/genética , Anafilaxia/imunologia , Animais , Artrite Experimental/genética , Artrite Experimental/imunologia , Carboxipeptidases A/genética , Carboxipeptidases A/metabolismo , Modelos Animais de Doenças , Encefalomielite Autoimune Experimental/genética , Encefalomielite Autoimune Experimental/imunologia , Perfilação da Expressão Gênica , Marcação de Genes , Predisposição Genética para Doença , Imunoglobulina E/imunologia , Mucosa Intestinal/imunologia , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Mastócitos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fator de Células-Tronco/deficiência , Linfócitos T/metabolismo , Células Th2/imunologia , Proteína Supressora de Tumor p53/metabolismoRESUMO
Mast cells are highly versatile in terms of their mode of activation by a host of stimuli and their ability to flexibly release a plethora of biologically highly active mediators. Within the immune system, mast cells can best be designated as an active nexus interlinking innate and adaptive immunity. Here we try to draw an arc from initiation of acute inflammatory reactions to microbial pathogens to development of adaptive immunity and allergies. This multifaceted nature of mast cells is made possible by interaction with multiple cell types of immunologic and nonimmunologic origin. Examples for the former include neutrophils, eosinophils, T cells, and professional antigen-presenting cells. These interactions allow mast cells to orchestrate inflammatory innate reactions and complex adaptive immunity, including the pathogenesis of allergies. Important partners of nonimmunologic origin include cells of the sensory neuronal system. The intimate association between mast cells and sensory nerve fibers allows bidirectional communication, leading to neurogenic inflammation. Evidence is accumulating that this mast cell/nerve crosstalk is of pathophysiologic relevance in patients with allergic diseases, such as asthma.
Assuntos
Imunidade Adaptativa , Asma/imunologia , Imunidade Inata , Mastócitos/imunologia , Animais , Células Apresentadoras de Antígenos/imunologia , Células Apresentadoras de Antígenos/patologia , Asma/patologia , Comunicação Celular/imunologia , Eosinófilos/imunologia , Eosinófilos/patologia , Humanos , Mastócitos/patologia , Neutrófilos/imunologia , Neutrófilos/patologia , Células Receptoras Sensoriais/imunologia , Células Receptoras Sensoriais/patologia , Linfócitos T/imunologia , Linfócitos T/patologiaRESUMO
Interferon-regulatory factor 4 (IRF4) is essential for the development of T helper 2 (Th2) and Th17 cells. Herein, we report that IRF4 is also crucial for the development and function of an interleukin-9 (IL-9)-producing CD4(+) T cell subset designated Th9. IRF4-deficient CD4(+) T cells failed to develop into IL-9-producing Th9 cells, and IRF4-specific siRNA inhibited IL-9 production in wild-type CD4(+) T cells. Chromatin-immunoprecipitation (ChIP) analyses revealed direct IRF4 binding to the Il9 promoter in Th9 cells. In a Th9-dependent asthma model, neutralization of IL-9 substantially ameliorated asthma symptoms. The relevance of these findings is emphasized by the fact that the induction of IL-9 production also occurs in human CD4(+) T cells accompanied by the upregulation of IRF4. Our data clearly demonstrate the central function of IRF4 in the development of Th9 cells and underline the contribution of this T helper cell subset to the pathogenesis of asthma.
Assuntos
Fatores Reguladores de Interferon/imunologia , Interleucina-9/imunologia , Linfócitos T Auxiliares-Indutores/imunologia , Animais , Asma/genética , Asma/imunologia , Diferenciação Celular , Células Cultivadas , Humanos , Fatores Reguladores de Interferon/deficiência , Fatores Reguladores de Interferon/genética , Fatores Reguladores de Interferon/metabolismo , Interleucina-9/biossíntese , Interleucina-9/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Regiões Promotoras Genéticas , Ligação Proteica , RNA Interferente Pequeno/genética , Linfócitos T Auxiliares-Indutores/citologiaAssuntos
Enterite , Hipersensibilidade , Animais , Enterite/etiologia , Humanos , Mastócitos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos KnockoutRESUMO
Coevolution of ticks and the vertebrate immune system has led to the development of immunosuppressive molecules that prevent immediate response of skin-resident immune cells to quickly fend off the parasite. In this article, we demonstrate that the tick-derived immunosuppressor sialostatin L restrains IL-9 production by mast cells, whereas degranulation and IL-6 expression are both unaffected. In addition, the expression of IL-1ß and IRF4 is strongly reduced in the presence of sialostatin L. Correspondingly, IRF4- or IL-1R-deficient mast cells exhibit a strong impairment in IL-9 production, demonstrating the importance of IRF4 and IL-1 in the regulation of the Il9 locus in mast cells. Furthermore, IRF4 binds to the promoters of Il1b and Il9, suggesting that sialostatin L suppresses mast cell-derived IL-9 preferentially by inhibiting IRF4. In an experimental asthma model, mast cell-specific deficiency in IRF4 or administration of sialostatin L results in a strong reduction in asthma symptoms, demonstrating the immunosuppressive potency of tick-derived molecules.
Assuntos
Cistatinas/farmacologia , Imunidade Inata/efeitos dos fármacos , Imunossupressores/farmacologia , Fatores Reguladores de Interferon/imunologia , Interleucina-9/imunologia , Mastócitos/efeitos dos fármacos , Animais , Asma/genética , Asma/imunologia , Asma/patologia , Sítios de Ligação , Degranulação Celular/imunologia , Cistatinas/imunologia , Regulação da Expressão Gênica , Interações Hospedeiro-Parasita/imunologia , Fatores Reguladores de Interferon/deficiência , Fatores Reguladores de Interferon/genética , Interleucina-1beta/genética , Interleucina-1beta/imunologia , Interleucina-6/genética , Interleucina-6/imunologia , Interleucina-9/antagonistas & inibidores , Interleucina-9/genética , Mastócitos/imunologia , Mastócitos/patologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Regiões Promotoras Genéticas , Ligação Proteica , Receptores de Interleucina-1/genética , Receptores de Interleucina-1/imunologia , Transdução de Sinais , Transcrição GênicaRESUMO
BACKGROUND: Cutaneous exposure to food allergens predisposes to food allergy, which is commonly associated with atopic dermatitis (AD). Levels of the epithelial cytokine IL-33 are increased in skin lesions and serum of patients with AD. Mast cells (MCs) play a critical role in food-induced anaphylaxis and express the IL-33 receptor ST2. The role of IL-33 in patients with MC-dependent food anaphylaxis is unknown. OBJECTIVE: We sought to determine the role and mechanism of action of IL-33 in patients with food-induced anaphylaxis in a model of IgE-dependent food anaphylaxis elicited by oral challenge of epicutaneously sensitized mice. METHODS: Wild-type, ST2-deficient, and MC-deficient KitW-sh/W-sh mice were epicutaneously sensitized with ovalbumin (OVA) and then challenged orally with OVA. Body temperature was measured by means of telemetry, Il33 mRNA by means of quantitative PCR, and IL-33, OVA-specific IgE, and mouse mast cell protease 1 by means of ELISA. Bone marrow-derived mast cell (BMMC) degranulation was assessed by using flow cytometry. RESULTS: Il33 mRNA expression was upregulated in tape-stripped mouse skin and scratched human skin. Tape stripping caused local and systemic IL-33 release in mice. ST2 deficiency, as well as ST2 blockade before oral challenge, significantly reduced the severity of oral anaphylaxis without affecting the systemic TH2 response to the allergen. Oral anaphylaxis was abrogated in KitW-sh/W-sh mice and restored by means of reconstitution with wild-type but not ST2-deficient BMMCs. IL-33 significantly enhanced IgE-mediated degranulation of BMMCs in vitro. CONCLUSION: IL-33 is released after mechanical skin injury, enhances IgE-mediated MC degranulation, and promotes oral anaphylaxis after epicutaneous sensitization by targeting MCs. IL-33 neutralization might be useful in treating food-induced anaphylaxis in patients with AD.
Assuntos
Anafilaxia/imunologia , Hipersensibilidade Alimentar/imunologia , Interleucina-33/imunologia , Mastócitos/imunologia , Administração Cutânea , Alérgenos/imunologia , Animais , Dermatite Atópica/imunologia , Feminino , Humanos , Imunoglobulina E/imunologia , Interleucina-33/genética , Camundongos Endogâmicos BALB C , Camundongos Transgênicos , Ovalbumina/imunologia , RNA Mensageiro/metabolismo , Pele/imunologiaRESUMO
The lungs are a noted predilection site of acute, latent, and reactivated cytomegalovirus (CMV) infections. Interstitial pneumonia is the most dreaded manifestation of CMV disease in the immunocompromised host, whereas in the immunocompetent host lung-infiltrating CD8 T cells confine the infection in nodular inflammatory foci and prevent viral pathology. By using murine CMV infection as a model, we provide evidence for a critical role of mast cells (MC) in the recruitment of protective CD8 T cells to the lungs. Systemic infection triggered degranulation selectively in infected MC. The viral activation of MC was associated with a wave of CC chemokine ligand 5 (CCL5) in the serum of C57BL/6 mice that was MC-derived as verified by infection of MC-deficient Kit(W-sh/W-sh) "sash" mutants. In these mutants, CD8 T cells were recruited less efficiently to the lungs, correlating with enhanced viral replication and delayed virus clearance. A causative role for MC was verified by MC reconstitution of "sash" mice restoring both, efficient CD8 T-cell recruitment and infection control. These results reveal a novel crosstalk axis between innate and adaptive immune defense against CMV, and identify MC as a hitherto unconsidered player in the immune surveillance at a relevant site of CMV disease.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Infecções por Herpesviridae/imunologia , Pulmão/imunologia , Mastócitos/imunologia , Muromegalovirus/imunologia , Pneumonia Viral/imunologia , Animais , Linfócitos T CD8-Positivos/patologia , Infecções por Herpesviridae/genética , Infecções por Herpesviridae/patologia , Pulmão/patologia , Pulmão/virologia , Mastócitos/patologia , Camundongos , Camundongos Mutantes , Muromegalovirus/metabolismo , Pneumonia Viral/genética , Pneumonia Viral/patologiaRESUMO
Cylindromatosis (CYLD) is a ubiquitously expressed deubiquitinating enzyme which removes activating ubiquitin residues from important signaling molecules of the NF-κB pathway. In CYLDex7/8 transgenic mice, a naturally occurring short isoform (sCYLD) is overexpressed in the absence of full length CYLD, leading to excessive NF-κB activity. Herein, we investigated the impact of the CYLDex7/8 mutation selectively in T cells on the development of experimental allergic airway disease induced by sensitization and challenge with ovalbumin. Compared with their wildtype littermates, mice bearing the T cell-specific mutation (CD4+CYLDex7/8) display stronger eosinophilia and mucus production in the lungs and higher IgE serum levels. The reason for these observations is excessive production of T cell-derived IL-9, a cytokine to whom allergy-promoting properties were ascribed. Consequently, blockade of IL-9 in CD4+CYLDex7/8 mice alleviates the development of disease symptoms. Thus, by polarization of the T cell cytokine response, sCYLD can favor the development of allergic airway disease.
Assuntos
Asma/genética , Linfócitos T CD4-Positivos/fisiologia , Eosinófilos/fisiologia , Hipersensibilidade/genética , Síndromes Neoplásicas Hereditárias/genética , Neoplasias Cutâneas/genética , Proteínas Supressoras de Tumor/metabolismo , Animais , Enzima Desubiquitinante CYLD , Humanos , Interleucina-9/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Modelos Animais , Muco/metabolismo , Mutação/genética , Proteínas Supressoras de Tumor/genéticaRESUMO
Signaling via the Wnt/ß-catenin pathway plays crucial roles in embryogenesis and homeostasis of adult tissues. In the lung, the canonical Wnt/ß-catenin pathway has been implicated in remodeling processes, development of emphysema, and fibrosis. However, its relevance for the modulation of allergic responses in the lung remains unclear. Using genetically modified mice with lung-specific inducible (doxycycline) Wnt-1 expression (CCSP-rtTA × tetO-Wnt1), the impact of Wnt on the development of allergic airway disease was analyzed. Overexpression of Wnt during the allergen challenge phase attenuated the development of airway inflammation in an acute model, as well as in a more therapeutic model of secondary challenge. These findings were further supported by treatment of allergen-sensitized mice with LiCl during challenge. Similar to Wnt, LiCl prevented the degradation of ß-catenin and, thus, attenuated allergic airway inflammation and hyperresponsiveness. Migration studies revealed that lung-specific expression of Wnt reduced the migration of Ag-loaded dendritic cells (DCs) into the draining lymph nodes following allergen challenge. Administration of in vitro allergen-loaded DCs overcame Wnt-mediated suppression of airway inflammation. Furthermore, in vitro studies confirmed that DC-dependent T cell activation is impaired by blocking ß-catenin degradation. These results demonstrate an important role for the canonical Wnt/ß-catenin pathway in the DC-mediated regulation of allergic responses in the lung.
Assuntos
Hipersensibilidade Respiratória/imunologia , Transdução de Sinais/imunologia , Proteína Wnt1/imunologia , beta Catenina/imunologia , Adjuvantes Imunológicos/farmacologia , Animais , Movimento Celular/genética , Movimento Celular/imunologia , Células Cultivadas , Técnicas de Cocultura , Citocinas/imunologia , Citocinas/metabolismo , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Doxiciclina/farmacologia , Citometria de Fluxo , Cloreto de Lítio/imunologia , Cloreto de Lítio/farmacologia , Pulmão/efeitos dos fármacos , Pulmão/metabolismo , Pulmão/fisiopatologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Ovalbumina/imunologia , Ovalbumina/farmacologia , Hipersensibilidade Respiratória/genética , Hipersensibilidade Respiratória/prevenção & controle , Transdução de Sinais/genética , Linfócitos T/imunologia , Linfócitos T/metabolismo , Proteína Wnt1/genética , Proteína Wnt1/metabolismo , beta Catenina/metabolismoRESUMO
Reactivation of latent cytomegalovirus (CMV) in the transient immunocompromised state after hematoablative treatment is a major concern in patients undergoing hematopoietic cell transplantation (HCT) as a therapy of hematopoietic malignancies. Timely reconstitution of antiviral CD8 T cells and their efficient recruitment to the lungs is crucial for preventing interstitial pneumonia, the most severe disease manifestation of CMV in HCT recipients. Here, we review recent work in a murine model, implicating mast cells (MC) in the control of pulmonary infection. Murine CMV (mCMV) productively infects MC in vivo and triggers their degranulation, resulting in the release of the CC chemokine ligand 5 (CCL5) that attracts CD8 T cells to infiltrate infected tissues. Comparing infection of MC-sufficient C57BL/6 mice and congenic MC-deficient Kit (W-sh/W-sh) "sash" mutants revealed an inverse relation between the number of lung-infiltrating CD8 T cells and viral burden in the lungs. Specifically, reduced lung infiltration by CD8 T cells in "sash" mutants was associated with an impaired infection control. The causal, though indirect, involvement of MC in antiviral control was confirmed by reversion of the deficiency phenotype in "sash" mutants reconstituted with MC. These recent findings predict that efficient MC reconstitution facilitates the control of CMV infection also in immunocompromised HCT recipients.
Assuntos
Mastócitos/imunologia , Mastócitos/metabolismo , Animais , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Degranulação Celular/genética , Degranulação Celular/imunologia , Quimiocina CCL5/biossíntese , Modelos Animais de Doenças , Infecções por Herpesviridae/genética , Infecções por Herpesviridae/imunologia , Infecções por Herpesviridae/metabolismo , Infecções por Herpesviridae/virologia , Imunidade Inata , Pulmão/imunologia , Pulmão/metabolismo , Pulmão/patologia , Pulmão/virologia , Mastócitos/virologia , Camundongos , Muromegalovirus/fisiologia , Tropismo Viral , Replicação ViralRESUMO
Mast cell-deficient Kit(W-sh) "sash" mice are widely used to investigate mast cell functions. However, mutations of c-Kit also affect additional cells of hematopoietic and nonimmune origin. In this study, we demonstrate that Kit(W-sh) causes aberrant extramedullary myelopoiesis characterized by the expansion of immature lineage-negative cells, common myeloid progenitors, and granulocyte/macrophage progenitors in the spleen. A consistent feature shared by these cell types is the reduced expression of c-Kit. Populations expressing intermediate and high levels of Ly6G, a component of the myeloid differentiation Ag Gr-1, are also highly expanded in the spleen of sash mice. These cells are able to suppress T cell responses in vitro and phenotypically and functionally resemble myeloid-derived suppressor cells (MDSC). MDSC typically accumulate in tumor-bearing hosts and are able to dampen immune responses. Consequently, transfer of MDSC from naive sash mice into line 1 alveolar cell carcinoma tumor-bearing wild-type littermates leads to enhanced tumor progression. However, although it can also be observed in sash mice, accelerated growth of transplanted line 1 alveolar cell carcinoma tumors is a mast cell-independent phenomenon. Thus, the Kit(W-sh) mutation broadly affects key steps in myelopoiesis that may have an impact on mast cell research.
Assuntos
Mastócitos/imunologia , Mutação , Células Mieloides/imunologia , Mielopoese/genética , Mielopoese/imunologia , Proteínas Proto-Oncogênicas c-kit/genética , Baço/citologia , Transferência Adotiva , Animais , Antígenos Ly/metabolismo , Antígeno CD11b/metabolismo , Feminino , Hematopoese Extramedular/genética , Hematopoese Extramedular/imunologia , Imunofenotipagem , Mastócitos/metabolismo , Camundongos , Camundongos Knockout , Células Mieloides/metabolismo , Transplante de Neoplasias , Neoplasias/imunologia , Neoplasias/patologia , Proteínas Proto-Oncogênicas c-kit/deficiência , Baço/imunologia , Baço/metabolismoRESUMO
Recent studies of mammalian genomes suggest that alternative promoters are associated with various disorders, including cancer. Here we present an intronic promoter of the murine proteinase 3 gene, which drives the expression of an alternative mRNA in intron 2 of the prtn3 gene. The proximal promoter sequences were identified and a series of promoter deletion constructs were used to identify the sequence elements that are required for basal promoter activity. Expression of the homeobox transcription factor CUX1 p75 isoform was found to suppress the activity of the alternative PR3 promoter. Data base analyses, multiple alignments and expression data showed that the intronic PR3 promoter is active in leukemia and other tumor cells as well as in mouse embryo, male mammary gland and bone marrow. In the spleen, the transcript is exclusively expressed by Gr-1(int) /CD11b(+) cells, which are also known as myeloid-derived suppressor cells (MDSCs). In humans, an alternative transcript of the PR3-gene could be detected in the bone marrow and in various cancer cell lines but not in primary leukemia cells, suggesting a species-overarching function of this kind of promoter. Therefore, the alternative PR3 promoter and its mRNA may be useful tools to investigate the fate of hematopoietic stem cells.
Assuntos
Íntrons , Neoplasias/genética , RNA não Traduzido/genética , Animais , Sequência de Bases , Linhagem Celular , Linhagem Celular Tumoral , Genes Homeobox/genética , Células HL-60 , Células HeLa , Proteínas de Homeodomínio/genética , Humanos , Células MCF-7 , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Dados de Sequência Molecular , Mieloblastina/genética , Células NIH 3T3 , Regiões Promotoras Genéticas , Fatores de Transcrição/genéticaRESUMO
Mast cells are able to trigger life-saving immune responses in murine models for acute inflammation. In such settings, several lines of evidence indicate that the rapid and protective recruitment of neutrophils initiated by the release of mast cell-derived pro-inflammatory mediators is a key element of innate immunity. Herein, we investigate the impact of mast cells on critical parameters of neutrophil effector function. In the presence of activated murine bone marrow-derived mast cells, neutrophils freshly isolated from bone marrow rapidly lose expression of CD62L and up-regulate CD11b, the latter being partly driven by mast cell-derived TNF and GM-CSF. Mast cells also strongly enhance neutrophil phagocytosis and generation of reactive oxygen species. All these phenomena partly depend on mast cell-derived TNF and to a greater extend on GM-CSF. Furthermore, spontaneous apoptosis of neutrophils is greatly diminished due to the ability of mast cells to deliver antiapoptotic GM-CSF. Finally, we show in a murine model for acute lung inflammation that neutrophil phagocytosis is impaired in mast cell-deficient Kit (W-sh) /Kit (W-sh) mice but can be restored upon mast cell engraftment. Thus, a previously underrated feature of mast cells is their ability to boost neutrophil effector functions in immune responses.
Assuntos
Fator Estimulador de Colônias de Granulócitos e Macrófagos/metabolismo , Mastócitos/imunologia , Neutrófilos/imunologia , Pneumonia/imunologia , Fator de Necrose Tumoral alfa/metabolismo , Animais , Apoptose , Células Cultivadas , Citometria de Fluxo , Fator Estimulador de Colônias de Granulócitos e Macrófagos/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Mutantes , Ativação de Neutrófilo/genética , Fagocitose/genética , Fator de Necrose Tumoral alfa/genéticaRESUMO
Epidemiological studies suggest that viral infections during childhood are a risk factor for the development of asthma. However, the role of virus-specific pattern recognition receptors in this process is not well defined. In the current study, we compare the effects of the inhaled viral TLR ligands polyinosinic-polycytidylic acid (TLR3) and resiquimod (TLR7/8) on sensitization to a model allergen (OVA) in a murine model. Both compounds enhance the migration, activation, and Ag-processing of myeloid dendritic cells from the lung to the draining lymph nodes comparable to the effects of LPS. Application of polyinosinic-polycytidylic acid [poly(I:C)] or LPS induces production of allergen-specific IgE and IgG1, whereas resiquimod (R848) had no effect. In addition, rechallenge of mice with OVA resulted in airway inflammation and mucus production in animals that received either poly(I:C) or LPS but not after application of R848. In summary, these results show that activation of TLR3 in combination with inhaled allergen results in induction of dendritic cell activation and migration similar to the effects of LPS. This leads to the development of allergic airway disease after allergen rechallenge, whereas mice treated with R848 did not develop allergic airway disease. These findings give further insight into the effects of stimulation of different TLRs on the development of asthma.
Assuntos
Alérgenos/administração & dosagem , Alérgenos/imunologia , Hipersensibilidade/imunologia , Glicoproteínas de Membrana/metabolismo , Receptor 3 Toll-Like/metabolismo , Receptor 7 Toll-Like/metabolismo , Receptor 8 Toll-Like/metabolismo , Administração por Inalação , Animais , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Modelos Animais de Doenças , Hipersensibilidade/microbiologia , Hipersensibilidade/virologia , Imidazóis/administração & dosagem , Imidazóis/metabolismo , Ligantes , Lipopolissacarídeos/administração & dosagem , Lipopolissacarídeos/metabolismo , Glicoproteínas de Membrana/agonistas , Glicoproteínas de Membrana/deficiência , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Ovalbumina/administração & dosagem , Ovalbumina/imunologia , Poli I-C/administração & dosagem , Poli I-C/metabolismo , Receptor 3 Toll-Like/deficiência , Receptor 7 Toll-Like/agonistas , Receptor 7 Toll-Like/deficiência , Receptor 8 Toll-Like/agonistasRESUMO
Ticks developed a multitude of different immune evasion strategies to obtain a blood meal. Sialostatin L is an immunosuppressive cysteine protease inhibitor present in the saliva of the hard tick Ixodes scapularis. In this study, we demonstrate that sialostatin L strongly inhibits the production of IL-9 by Th9 cells. Because we could show recently that Th9-derived IL-9 is essentially involved in the induction of asthma symptoms, sialostatin L was used for the treatment of experimental asthma. Application of sialostatin L in a model of experimental asthma almost completely abrogated airway hyperresponsiveness and eosinophilia. Our data suggest that sialostatin L can prevent experimental asthma, most likely by inhibiting the IL-9 production of Th9 cells. Thus, alternative to IL-9 neutralization sialostatin L provides the basis for the development of innovative therapeutic strategies to treat asthma.
Assuntos
Asma/imunologia , Cistatinas/imunologia , Interleucina-9/imunologia , Ixodidae/imunologia , Subpopulações de Linfócitos T/imunologia , Animais , Asma/metabolismo , Asma/prevenção & controle , Separação Celular , Cistatinas/farmacologia , Citocinas/imunologia , Citocinas/metabolismo , Modelos Animais de Doenças , Ensaio de Imunoadsorção Enzimática , Feminino , Citometria de Fluxo , Interleucina-9/biossíntese , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Subpopulações de Linfócitos T/metabolismoRESUMO
Naturally occurring regulatory T cells (T reg cells) are a thymus-derived subset of T cells, which are crucial for the maintenance of peripheral tolerance by controlling potentially autoreactive T cells. However, the underlying molecular mechanisms of this strictly cell contact-dependent process are still elusive. Here we show that naturally occurring T reg cells harbor high levels of cyclic adenosine monophosphate (cAMP). This second messenger is known to be a potent inhibitor of proliferation and interleukin 2 synthesis in T cells. Upon coactivation with naturally occurring T reg cells the cAMP content of responder T cells is also strongly increased. Furthermore, we demonstrate that naturally occurring T reg cells and conventional T cells communicate via cell contact-dependent gap junction formation. The suppressive activity of naturally occurring T reg cells is abolished by a cAMP antagonist as well as by a gap junction inhibitor, which blocks the cell contact-dependent transfer of cAMP to responder T cells. Accordingly, our results suggest that cAMP is crucial for naturally occurring T reg cell-mediated suppression and traverses membranes via gap junctions. Hence, naturally occurring T reg cells unexpectedly may control the immune regulatory network by a well-known mechanism based on the intercellular transport of cAMP via gap junctions.
Assuntos
Linfócitos T CD4-Positivos/imunologia , AMP Cíclico/imunologia , Sistemas do Segundo Mensageiro/imunologia , Fatores Supressores Imunológicos/imunologia , Linfócitos T Reguladores/imunologia , Animais , Conexinas , Citocinas/metabolismo , Primers do DNA , Ensaio de Imunoadsorção Enzimática , Feminino , Junções Comunicantes/imunologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Oligopeptídeos , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Asthma is a syndrome with different inflammatory phenotypes. Animal models have shown that, after sensitization and allergen challenge, Th2 and Th1 cells contribute to the development of allergic airway disease. We have previously demonstrated that naturally occurring regulatory T cells (nTregs) can only marginally suppress Th2-induced airway inflammation and airway hyperresponsiveness. In this study, we investigated nTreg-mediated suppression of Th2-induced and Th1-induced acute allergic airway disease. We demonstrate in vivo that nTregs exert their suppressive potency via cAMP transfer on Th2- and Th1-induced airway disease. A comparison of both phenotypes revealed that, despite similar cAMP transfers, Th1-driven airway hyperresponsiveness and inflammation are more susceptible to nTreg-dependent suppression, suggesting that potential nTreg-based therapeutic strategies might be more effective in patients with predominantly neutrophilic airway inflammation based on deregulated Th1 response.
Assuntos
Hiper-Reatividade Brônquica/imunologia , Modelos Animais de Doenças , Linfócitos T Reguladores/imunologia , Células Th1/imunologia , Células Th2/imunologia , Doença Aguda , Animais , Hiper-Reatividade Brônquica/patologia , Hiper-Reatividade Brônquica/prevenção & controle , Células Cultivadas , Técnicas de Cocultura , Suscetibilidade a Doenças/imunologia , Suscetibilidade a Doenças/patologia , Feminino , Imunidade Inata , Inflamação/imunologia , Inflamação/patologia , Inflamação/prevenção & controle , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Camundongos Transgênicos , Linfócitos T Reguladores/patologia , Células Th1/patologia , Células Th2/patologiaRESUMO
Mast cell-deficient mice are a key for investigating the function of mast cells in health and disease. Allergic airway disease induced as a Th2-type immune response in mice is employed as a model to unravel the mechanisms underlying inception and progression of human allergic asthma. Previous work done in mast cell-deficient mouse strains that otherwise typically mount Th1-dominated immune responses revealed contradictory results as to whether mast cells contribute to the development of airway hyperresponsiveness and airway inflammation. However, a major contribution of mast cells was shown using adjuvant-free protocols to achieve sensitization. The identification of a traceable genetic polymorphism closely linked to the Kit(W-sh) allele allowed us to generate congenic mast cell-deficient mice on a Th2-prone BALB/c background, termed C.B6-Kit(W-sh). In accordance with the expectations, C.B6-Kit(W-sh) mice do not develop IgE- and mast cell-dependent passive cutaneous anaphylaxis. Yet, unexpectedly, C.B6-Kit(W-sh) mice develop full-blown airway inflammation, airway hyperresponsiveness, and mucus production despite the absence of mast cells. Thus, our findings demonstrate a major influence of genetic background on the contribution of mast cells in an important disease model and introduce a novel strain of mast cell-deficient mice.
Assuntos
Asma/imunologia , Mastócitos/imunologia , Polimorfismo Genético , Animais , Asma/genética , Asma/patologia , Hiper-Reatividade Brônquica , Contagem de Células , Inflamação , Mastócitos/patologia , Camundongos , Camundongos Congênicos , Células Th2RESUMO
Tumor development and progression is shaped by the tumor microenvironment (TME), a heterogeneous assembly of infiltrating and resident host cells, their secreted mediators and intercellular matrix. In this context, tumors are infiltrated by various immune cells with either pro-tumoral or anti-tumoral functions. Recently, we published our non-invasive immunization platform DIVA suitable as a therapeutic vaccination method, further optimized by repeated application (DIVA2). In our present work, we revealed the therapeutic effect of DIVA2 in an MC38 tumor model and specifically focused on the mechanisms induced in the TME after immunization. DIVA2 resulted in transient tumor control followed by an immune evasion phase within three weeks after the initial tumor inoculation. High-dimensional flow cytometry analysis and single-cell mRNA-sequencing of tumor-infiltrating leukocytes revealed cytotoxic CD8+ T cells as key players in the immune control phase. In the immune evasion phase, inflammatory CCR2+ PDL-1+ monocytes with immunosuppressive properties were recruited into the tumor leading to suppression of DIVA2-induced tumor-reactive T cells. Depletion of CCR2+ cells with specific antibodies resulted in prolonged survival revealing CCR2+ monocytes as important for tumor immune escape in the TME. In summary, the present work provides a platform for generating a strong antigen-specific primary and memory T cell immune response using the optimized transcutaneous immunization method DIVA2. This enables protection against tumors by therapeutic immune control of solid tumors and highlights the immunosuppressive influence of tumor infiltrating CCR2+ monocytes that need to be inactivated in addition for successful cancer immunotherapy.