RESUMO
Foxp3+ regulatory T cells (Treg cells) are crucial for the maintenance of immune homeostasis both in lymphoid tissues and in non-lymphoid tissues. Here we demonstrate that the ability of intestinal Treg cells to constrain microbiota-dependent interleukin (IL)-17-producing helper T cell (TH17 cell) and immunoglobulin A responses critically required expression of the transcription factor c-Maf. The terminal differentiation and function of several intestinal Treg cell populations, including RORγt+ Treg cells and follicular regulatory T cells, were c-Maf dependent. c-Maf controlled Treg cell-derived IL-10 production and prevented excessive signaling via the kinases PI(3)K (phosphatidylinositol-3-OH kinase) and Akt and the metabolic checkpoint kinase complex mTORC1 (mammalian target of rapamycin) and expression of inflammatory cytokines in intestinal Treg cells. c-Maf deficiency in Treg cells led to profound dysbiosis of the intestinal microbiota, which when transferred to germ-free mice was sufficient to induce exacerbated intestinal TH17 responses, even in a c-Maf-competent environment. Thus, c-Maf acts to preserve the identity and function of intestinal Treg cells, which is essential for the establishment of host-microbe symbiosis.
Assuntos
Imunoglobulina A/biossíntese , Intestinos/imunologia , Microbiota , Proteínas Proto-Oncogênicas c-maf/fisiologia , Linfócitos T Reguladores/imunologia , Células Th17/imunologia , Animais , Células Cultivadas , Colite/imunologia , Citocinas/metabolismo , Disbiose , Regulação da Expressão Gênica , Homeostase , Interleucina-10/biossíntese , Camundongos Endogâmicos C57BL , Proteínas Proto-Oncogênicas c-maf/genética , Proteínas Proto-Oncogênicas c-maf/metabolismo , Linfócitos T Reguladores/enzimologiaRESUMO
Solitary intestinal lymphoid tissues such as cryptopatches (CPs) and isolated lymphoid follicles (ILFs) constitute steady-state activation hubs containing group 3 innate lymphoid cells (ILC3) that continuously produce interleukin (IL)-22. The outer surface of CPs and ILFs is demarcated by a poorly characterized population of CD11c+ cells. Using genome-wide single-cell transcriptional profiling of intestinal mononuclear phagocytes and multidimensional flow cytometry, we found that CP- and ILF-associated CD11c+ cells were a transcriptionally distinct subset of intestinal cDCs, which we term CIA-DCs. CIA-DCs required programming by CP- and ILF-resident CCR6+ ILC3 via lymphotoxin-ß receptor signaling in cDCs. CIA-DCs differentially expressed genes associated with immunoregulation and were the major cellular source of IL-22 binding protein (IL-22BP) at steady state. Mice lacking CIA-DC-derived IL-22BP exhibited diminished expression of epithelial lipid transporters, reduced lipid resorption, and changes in body fat homeostasis. Our findings provide insight into the design principles of an immunoregulatory checkpoint controlling nutrient absorption.
Assuntos
Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Imunidade Inata , Subpopulações de Linfócitos/imunologia , Subpopulações de Linfócitos/metabolismo , Nódulos Linfáticos Agregados/citologia , Nódulos Linfáticos Agregados/imunologia , Receptores de Interleucina/biossíntese , Animais , Biomarcadores , Expressão Gênica , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Imunofenotipagem , Mucosa Intestinal/imunologia , Mucosa Intestinal/metabolismo , Metabolismo dos Lipídeos , Camundongos , Camundongos Transgênicos , RNA Citoplasmático Pequeno/genética , Receptores de Interleucina/genética , Transdução de SinaisRESUMO
SARS-CoV-2 is a single-stranded RNA virus that causes COVID-19. Given its acute and often self-limiting course, it is likely that components of the innate immune system play a central part in controlling virus replication and determining clinical outcome. Natural killer (NK) cells are innate lymphocytes with notable activity against a broad range of viruses, including RNA viruses1,2. NK cell function may be altered during COVID-19 despite increased representation of NK cells with an activated and adaptive phenotype3,4. Here we show that a decline in viral load in COVID-19 correlates with NK cell status and that NK cells can control SARS-CoV-2 replication by recognizing infected target cells. In severe COVID-19, NK cells show defects in virus control, cytokine production and cell-mediated cytotoxicity despite high expression of cytotoxic effector molecules. Single-cell RNA sequencing of NK cells over the time course of the COVID-19 disease spectrum reveals a distinct gene expression signature. Transcriptional networks of interferon-driven NK cell activation are superimposed by a dominant transforming growth factor-ß (TGFß) response signature, with reduced expression of genes related to cell-cell adhesion, granule exocytosis and cell-mediated cytotoxicity. In severe COVID-19, serum levels of TGFß peak during the first two weeks of infection, and serum obtained from these patients severely inhibits NK cell function in a TGFß-dependent manner. Our data reveal that an untimely production of TGFß is a hallmark of severe COVID-19 and may inhibit NK cell function and early control of the virus.
Assuntos
COVID-19/imunologia , Células Matadoras Naturais/imunologia , SARS-CoV-2/imunologia , Fator de Crescimento Transformador beta/imunologia , Atlas como Assunto , Regulação da Expressão Gênica/imunologia , Humanos , Imunidade Inata , Influenza Humana/imunologia , Células Matadoras Naturais/patologia , RNA-Seq , Análise de Célula Única , Fatores de Tempo , Fator de Crescimento Transformador beta/sangue , Carga Viral/imunologia , Replicação Viral/imunologiaRESUMO
COVID-19 is a systemic inflammatory disease initiated by SARS-CoV-2 virus infection. Multiple vaccines against the Wuhan variant of SARS-CoV-2 have been developed including a whole virion beta-propiolactone-inactivated vaccine based on the B.1.1 strain (CoviVac). Since most of the population has been vaccinated by targeting the original or early variants of SARS-CoV-2, the emergence of novel mutant variants raises concern over possible evasion of vaccine-induced immune responses. Here, we report on the mechanism of protection by CoviVac, a whole virion-based vaccine, against the Omicron variant. CoviVac-immunized K18-hACE2 Tg mice were protected against both prototype B.1.1 and BA.1-like (Omicron) variants. Subsequently, vaccinated K18-hACE2 Tg mice rapidly cleared the infection via cross-reactive T-cell responses and cross-reactive, non-neutralizing antibodies recognizing the Omicron variant Spike protein. Thus, our data indicate that efficient protection from SARS-CoV-2 variants can be achieved by the orchestrated action of cross-reactive T cells and non-neutralizing antibodies.
Assuntos
COVID-19 , Melfalan , SARS-CoV-2 , gama-Globulinas , Animais , Humanos , Camundongos , Vacinas de Produtos Inativados , Formação de Anticorpos , COVID-19/prevenção & controle , Linfócitos T , Vírion , Anticorpos Amplamente Neutralizantes , Anticorpos Neutralizantes , Anticorpos AntiviraisRESUMO
Although in normal lamina propria (LP) large numbers of eosinophils are present, little is known about their role in mucosal immunity at steady state. Here we show that eosinophils are needed to maintain immune homeostasis in gut-associated tissues. By using eosinophil-deficient ΔdblGATA-1 and PHIL mice or an eosinophil-specific depletion model, we found a reduction in immunoglobulin A(+) (IgA(+)) plasma cell numbers and in secreted IgA. Eosinophil-deficient mice also showed defects in the intestinal mucous shield and alterations in microbiota composition in the gut lumen. In addition, TGF-ß-dependent events including class switching to IgA in Peyer's patches (PP), the formation of CD103(+) T cells including Foxp3(+) regulatory (Treg), and also CD103(+) dendritic cells were disturbed. In vitro cultures showed that eosinophils produce factors that promote T-independent IgA class switching. Our findings show that eosinophils are important players for immune homeostasis in gut-associated tissues and add to data suggesting that eosinophils can promote tissue integrity.
Assuntos
Células Dendríticas/imunologia , Eosinófilos/metabolismo , Intestinos/imunologia , Plasmócitos/imunologia , Linfócitos T Reguladores/imunologia , Animais , Antígenos CD/metabolismo , Diferenciação Celular/genética , Células Cultivadas , Eosinófilos/imunologia , Fatores de Transcrição Forkhead , Homeostase , Imunidade nas Mucosas , Imunoglobulina A/metabolismo , Switching de Imunoglobulina/genética , Cadeias alfa de Integrinas/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microbiota/genética , Nódulos Linfáticos Agregados/imunologiaRESUMO
BACKGROUND & AIMS: Studies investigating the gut-liver axis have largely focused on bacteria, whereas little is known about commensal fungi. We characterized fecal fungi in patients with non-alcoholic fatty liver disease (NAFLD) and investigated their role in a fecal microbiome-humanized mouse model of Western diet-induced steatohepatitis. METHODS: We performed fungal internal transcribed spacer 2 sequencing using fecal samples from 78 patients with NAFLD, 16 controls and 73 patients with alcohol use disorder. Anti-Candida albicans (C. albicans) IgG was measured in blood samples from 17 controls and 79 patients with NAFLD. Songbird, a novel multinominal regression tool, was used to investigate mycobiome changes. Germ-free mice were colonized with feces from patients with non-alcoholic steatohepatitis (NASH), fed a Western diet for 20 weeks and treated with the antifungal amphotericin B. RESULTS: The presence of non-obese NASH or F2-F4 fibrosis was associated with a distinct fecal mycobiome signature. Changes were characterized by an increased log-ratio for Mucor sp./Saccharomyces cerevisiae (S. cerevisiae) in patients with NASH and F2-F4 fibrosis. The C. albicans/S. cerevisiae log-ratio was significantly higher in non-obese patients with NASH when compared with non-obese patients with NAFL or controls. We observed a different fecal mycobiome composition in patients with NAFLD and advanced fibrosis compared to those with alcohol use disorder and advanced fibrosis. Plasma anti-C. albicans IgG was increased in patients with NAFLD and advanced fibrosis. Gnotobiotic mice, colonized with human NASH feces and treated with amphotericin B were protected from Western diet-induced steatohepatitis. CONCLUSIONS: Non-obese patients with NAFLD and more advanced disease have a different fecal mycobiome composition to those with mild disease. Antifungal treatment ameliorates diet-induced steatohepatitis in mice. Intestinal fungi could be an attractive target to attenuate NASH. LAY SUMMARY: Non-alcoholic fatty liver disease is one of the most common chronic liver diseases and is associated with changes in the fecal bacterial microbiome. We show that patients with non-alcoholic fatty liver disease and more severe disease stages have a specific composition of fecal fungi and an increased systemic immune response to Candida albicans. In a fecal microbiome-humanized mouse model of Western diet-induced steatohepatitis, we show that treatment with antifungals reduces liver damage.
Assuntos
Microbioma Gastrointestinal , Micobioma , Hepatopatia Gordurosa não Alcoólica , Animais , Fezes/microbiologia , Humanos , Fígado , Camundongos , Hepatopatia Gordurosa não Alcoólica/etiologia , Saccharomyces cerevisiaeRESUMO
Helper T (Th) cells play a decisive role in triggering and maintaining chronic rheumatic inflammation. Via secretion of proinflammatory cytokines and expression of costimulatory cell surface molecules, Th lymphocytes coordinate the recruitment and activation of effector cells, which are ultimately responsible for the immunopathology and tissue destruction. However, therapeutic approaches aimed at eliminating Th cells were unsuccessful due to their lack of selectivity. At the German Rheumatism Research Center (Deutsches Rheuma-Forschungszentrum, DRFZ), we are working to improve the understanding of the Th cells involved in chronic inflammatory reactions. Based on this understanding, our aim is to develop novel treatment strategies that selectively target the pathogenic Th lymphocytes causing rheumatic inflammation. The current article summarizes the DRFZ's research activities on this subject.
Assuntos
Doenças Reumáticas , Linfócitos T , Citocinas , Humanos , Inflamação/patologia , Linfócitos T/patologia , Linfócitos T Auxiliares-IndutoresRESUMO
BACKGROUND & AIMS: A substantial proportion patients with inflammatory bowel disease (IBD) have a primary non-response to infliximab; markers are needed to identify patients most likely to respond to treatment. We investigated whether production of tumor necrosis factor (TNF) by peripheral blood mononuclear cells (PBMCs) can be used as a marker to predict response. METHODS: We performed a prospective study of 41 adults with IBD (mean age, 38 years; 21 male; 21 with Crohn's disease and 20 with ulcerative colitis) not treated with a biologic agent within the past 6 months; patients were given their first infusion of infliximab at a hospital or clinic in Berlin, Germany. We collected data on clinical scores, levels of C-reactive protein, and ultrasound results (Limberg scores) at baseline (before the first infusion) and after 6 weeks (3rd infliximab infusion). PMBCs were obtained from patients at baseline and 10 healthy individuals (controls) and incubated with lipopolysaccharide. We measured production of cytokines (TNF, interleukin 1 [IL1], IL6, IL8, IL10, IL12p70, and IL22) by ELISA and performed cytometric bead array and flow cytometry analyses. The primary endpoint was clinical response (decrease in Harvey Bradshaw Index scores of 2 or more or decrease in partial Mayo scores of 3 or more at week 6) in patients with PBMCs that produced high vs low levels of TNF. RESULTS: Responders had a shorter median disease duration (P = .018) and higher median Limberg score (P = .021), than nonresponders. Baseline PBMCs from responders produced significantly more TNF (P = .049) and IL6 (P = .028) than from nonresponders; a level of 500 pg/ml TNF identified responders with 82% sensitivity and 78% specificity. In patients with Crohn's disease, this cutoff value (500 pg/ml TNF) identified responders with 100% sensitivity and 82% specificity; TNF levels above this level were independently associated with response to infliximab in multivariate analysis (odds ratio, 16.2; 95% CI, 1.8-148.7; P = .014). The percentage of TNF-positive cells was higher among CD14+ monocytes than lymphocytes after stimulation. CONCLUSIONS: Production of a high level of TNF by PBMCs (specifically CD14+ cells) from patients with IBD can identify those most likely to have a clinical response to infliximab therapy. In patients with Crohn's disease, a cutoff value of 500 pg/ml TNF identified responders with 100% sensitivity and 82% specificity.
Assuntos
Doenças Inflamatórias Intestinais , Leucócitos Mononucleares , Adulto , Humanos , Doenças Inflamatórias Intestinais/tratamento farmacológico , Infliximab/uso terapêutico , Masculino , Estudos Prospectivos , Fatores de Necrose TumoralRESUMO
BACKGROUND & AIMS: Unregulated activity of interleukin (IL) 22 promotes intestinal tumorigenesis in mice. IL22 binds the antagonist IL22 subunit alpha 2 (IL22RA2, also called IL22BP). We studied whether alterations in IL22BP contribute to colorectal carcinogenesis in humans and mice. METHODS: We obtained tumor and nontumor tissues from patients with colorectal cancer (CRC) and measured levels of cytokines by quantitative polymerase chain reaction, flow cytometry, and immunohistochemistry. We measured levels of Il22bp messenger RNA in colon tissues from wild-type, Tnf-/-, Lta-/-, and Ltb-/- mice. Mice were given azoxymethane and dextran sodium sulfate to induce colitis and associated cancer or intracecal injections of MC38 tumor cells. Some mice were given inhibitors of lymphotoxin beta receptor (LTBR). Intestine tissues were analyzed by single-cell sequencing to identify cell sources of lymphotoxin. We performed immunohistochemistry analysis of colon tissue microarrays from patients with CRC (1475 tissue cores, contained tumor and nontumor tissues) and correlated levels of IL22BP with patient survival times. RESULTS: Levels of IL22BP were decreased in human colorectal tumors, compared with nontumor tissues, and correlated with levels of lymphotoxin. LTBR signaling was required for expression of IL22BP in colon tissues of mice. Wild-type mice given LTBR inhibitors had an increased tumor burden in both models, but LTBR inhibitors did not increase tumor growth in Il22bp-/- mice. Lymphotoxin directly induced expression of IL22BP in cultured human monocyte-derived dendritic cells via activation of nuclear factor κB. Reduced levels of IL22BP in colorectal tumor tissues were associated with shorter survival times of patients with CRC. CONCLUSIONS: Lymphotoxin signaling regulates expression of IL22BP in colon; levels of IL22BP are reduced in human colorectal tumors, associated with shorter survival times. LTBR signaling regulates expression of IL22BP in colon tumors in mice and cultured human dendritic cells. Patients with colorectal tumors that express low levels of IL22BP might benefit from treatment with an IL22 antagonist.
Assuntos
Neoplasias Colorretais/metabolismo , Linfotoxina-alfa/metabolismo , Receptores de Interleucina/metabolismo , Idoso , Animais , Neoplasias Colorretais/mortalidade , Neoplasias Colorretais/patologia , Modelos Animais de Doenças , Feminino , Humanos , Masculino , Camundongos , RNA Mensageiro/metabolismo , Receptores de Interleucina/genética , Taxa de SobrevidaRESUMO
In humans and mice, mucosal immune responses are dominated by IgA antibodies and the cytokine TGF-ß, suppressing unwanted immune reactions but also targeting Ig class switching to IgA. It had been suggested that eosinophils promote the generation and maintenance of mucosal IgA-expressing plasma cells. Here, we demonstrate that not eosinophils, but specific bacteria determine mucosal IgA production. Co-housing of eosinophil-deficient mice with mice having high intestinal IgA levels, as well as the intentional microbiota transfer induces TGF-ß expression in intestinal T follicular helper cells, thereby promoting IgA class switching in Peyer's patches, enhancing IgA+ plasma cell numbers in the small intestinal lamina propria and levels of mucosal IgA. We show that bacteria highly enriched for the genus Anaeroplasma are sufficient to induce these changes and enhance IgA levels when adoptively transferred. Thus, specific members of the intestinal microbiota and not the microbiota as such regulate gut homeostasis, by promoting the expression of immune-regulatory TGF-ß and of mucosal IgA.
Assuntos
Microbioma Gastrointestinal/imunologia , Imunidade nas Mucosas , Imunoglobulina A/imunologia , Mucosa Intestinal , Nódulos Linfáticos Agregados , Linfócitos T Auxiliares-Indutores/imunologia , Animais , Mucosa Intestinal/imunologia , Mucosa Intestinal/microbiologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Nódulos Linfáticos Agregados/imunologia , Nódulos Linfáticos Agregados/microbiologia , Tenericutes/imunologiaRESUMO
TNF is a multifunctional cytokine involved in autoimmune disease pathogenesis that exerts its effects through two distinct TNF receptors, TNFR1 and TNFR2. While TNF- and TNFR1-deficient (but not TNFR2-deficient) mice show very similar phenotypes, the significance of TNFR2 signaling in health and disease remains incompletely understood. Recent studies implicated the importance of the TNF/TNFR2 axis in T regulatory (Treg) cell functions. To definitively ascertain the significance of TNFR2 signaling, we generated and validated doubly humanized TNF/TNFR2 mice, with the option of conditional inactivation of TNFR2. These mice carry a functional human TNF-TNFR2 (hTNF-hTNFR2) signaling module and provide a useful tool for comparative evaluation of TNF-directed biologics. Conditional inactivation of TNFR2 in FoxP3+ cells in doubly humanized TNF/TNFR2 mice down-regulated the expression of Treg signature molecules (such as FoxP3, CD25, CTLA-4, and GITR) and diminished Treg suppressive function in vitro. Consequently, Treg-restricted TNFR2 deficiency led to significant exacerbation of experimental autoimmune encephalomyelitis (EAE), accompanied by reduced capacity to control Th17-mediated immune responses. Our findings expose the intrinsic and beneficial effects of TNFR2 signaling in Treg cells that could translate into protective functions in vivo, including treatment of autoimmunity.
Assuntos
Autoimunidade/imunologia , Sistema Nervoso Central/imunologia , Modelos Animais de Doenças , Encefalomielite Autoimune Experimental/prevenção & controle , Receptores Tipo II do Fator de Necrose Tumoral/fisiologia , Linfócitos T Reguladores/imunologia , Fator de Necrose Tumoral alfa/fisiologia , Animais , Células Cultivadas , Sistema Nervoso Central/metabolismo , Sistema Nervoso Central/patologia , Encefalomielite Autoimune Experimental/imunologia , Encefalomielite Autoimune Experimental/metabolismo , Regulação da Expressão Gênica , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos KnockoutRESUMO
It is well accepted that Th17 cells are a highly plastic cell subset that can be easily directed toward the Th1 phenotype in vitro and also in vivo during inflammation. However, there is an ongoing debate regarding the reverse plasticity (conversion from Th1 to Th17). We show here that ectopic ROR-γt expression can restore or initiate IL-17 expression by non-classic or classic Th1 cells, respectively, while common pro-Th17 cytokine cocktails are ineffective. This stability of the Th1 phenotype is at least partially due to the presence of a molecular machinery governed by the transcription factor Eomes, which promotes IFN-γ secretion while inhibiting the expression of ROR-γt and IL-17. By using a mouse model of T cell-dependent colitis we demonstrate that Eomes controls non-classic Th1 cell development also in vivo and promotes their pathogenic potential. Eomes expression associates to a highly inflammatory phenotype also in patients with juvenile idiopathic arthritis. Indeed, it favors the acquisition of a cytotoxic signature, and promotes the development of IFN-γ+ GM-CSF+ cells that have been described to be pathogenic in chronic inflammatory disorders.
Assuntos
Artrite Juvenil/imunologia , Inflamação/imunologia , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/metabolismo , Proteínas com Domínio T/metabolismo , Subpopulações de Linfócitos T/imunologia , Células Th1/imunologia , Células Th17/imunologia , Animais , Diferenciação Celular , Plasticidade Celular , Células Cultivadas , Humanos , Interferon gama/metabolismo , Interleucina-17/metabolismo , Camundongos , Camundongos Knockout , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/genética , Proteínas com Domínio T/genéticaRESUMO
Bone marrow (BM) stromal cells are important in the development and maintenance of cells of the immune system. Using single cell RNA sequencing, we here explore the functional and phenotypic heterogeneity of individual transcriptomes of 1167 murine BM mesenchymal stromal cells. These cells exhibit a tremendous heterogeneity of gene expression, which precludes the identification of defined subpopulations. However, according to the expression of 108 genes involved in the communication of stromal cells with hematopoietic cells, we have identified 14 non-overlapping subpopulations, with distinct cytokine or chemokine gene expression signatures. With respect to the maintenance of subsets of immune memory cells by stromal cells, we identified distinct subpopulations expressing Il7, Il15 and Tnfsf13b. Together, this study provides a comprehensive dissection of the BM stromal heterogeneity at the single cell transcriptome level and provides a basis to understand their lifestyle and their role as organizers of niches for the long-term maintenance of immune cells.
Assuntos
Células da Medula Óssea/citologia , Medula Óssea/fisiologia , Células Estromais/citologia , Transcriptoma/genética , Animais , Fator Ativador de Células B/genética , Células Cultivadas , Citocinas/genética , Células-Tronco Hematopoéticas/citologia , Interleucina-15/genética , Interleucina-7/genética , Células-Tronco Mesenquimais/citologia , Camundongos , Camundongos Endogâmicos C57BL , Análise de Sequência de RNA/métodosRESUMO
OBJECTIVES: Neutralisation of tumour necrosis factor (TNF) is widely used as a therapy for rheumatoid arthritis (RA). However, this therapy is only effective in less than a half of patients and is associated with several side effects. We hypothesised that TNF may possess non-redundant protective and immunomodulatory functions in vivo that cannot be blocked without a cost. The present work aimed to identify cellular sources of protective and pathogenic TNF, and its molecular forms during autoimmune arthritis. METHODS: Mice lacking TNF expression by distinct cell types, such as myeloid cells and T or B lymphocytes, were subjected to collagen-induced arthritis (CIA) and collagen antibody-induced arthritis. Mice lacking soluble TNF production were also employed. The severity and incidence of the disease, as well as humoral and cellular responses were assessed. RESULTS: Myeloid cell-derived TNF contributes to both induction and pathogenesis of autoimmune arthritis. Conversely, T cell-derived TNF is protective during the induction phase of arthritis via limiting of interleukin-12 production by dendritic cells and by subsequent control of autoreactive memory T cell development, but is dispensable during the effector phase of arthritis. B cell-derived TNF mediates severity of CIA via control of pathogenic autoantibody production. CONCLUSIONS: Distinct TNF-producing cell types may modulate disease development through different mechanisms, suggesting that in arthritis TNF ablation from restricted cellular sources, such as myeloid cells, while preserving protective TNF functions from other cell types may be superior to pan-anti-TNF therapy.
Assuntos
Artrite Experimental/imunologia , Células Mieloides/imunologia , Fator de Necrose Tumoral alfa/imunologia , Animais , Artrite Experimental/metabolismo , Artrite Experimental/patologia , Linfócitos B/imunologia , Linfócitos B/metabolismo , Camundongos , Camundongos Knockout , Células Mieloides/metabolismo , Linfócitos T/imunologia , Linfócitos T/metabolismo , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Antinuclear antibodies are a hallmark feature of generalized autoimmune diseases, including systemic lupus erythematosus and systemic sclerosis. However, the processes underlying the loss of tolerance against nuclear self-constituents remain largely unresolved. Using mice deficient in lymphotoxin and Hox11, we report that approximately 25% of mice lacking secondary lymphoid organs spontaneously develop specific antinuclear antibodies. Interestingly, we find this phenotype is not caused by a defect in central tolerance. Rather, cell-specific deletion and in vivo lymphotoxin blockade link these systemic autoimmune responses to the formation of gut-associated lymphoid tissue in the neonatal period of life. We further demonstrate antinuclear antibody production is influenced by the presence of commensal gut flora, in particular increased colonization with segmented filamentous bacteria, and IL-17 receptor signaling. Together, these data indicate that neonatal colonization of gut microbiota influences generalized autoimmunity in adult life.
Assuntos
Autoimunidade/imunologia , Microbiota/imunologia , Animais , Anticorpos Antinucleares/genética , Anticorpos Antinucleares/imunologia , Autoimunidade/genética , Feminino , Citometria de Fluxo , Linfotoxina-alfa/genética , Linfotoxina-alfa/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Gravidez , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismoRESUMO
UNLABELLED: The B cell-activating factor (BAFF) is critical for B cell development and humoral immunity in mice and humans. While the role of BAFF in B cells has been widely described, its role in innate immunity remains unknown. Using BAFF receptor (BAFFR)-deficient mice, we characterized BAFFR-related innate and adaptive immune functions following infection with vesicular stomatitis virus (VSV) and lymphocytic choriomeningitis virus (LCMV). We identified a critical role for BAFFR signaling in the generation and maintenance of the CD169(+) macrophage compartment. Consequently, Baffr(-) (/) (-) mice exhibited limited induction of innate type I interferon production after viral infection. Lack of BAFFR signaling reduced virus amplification and presentation following viral infection, resulting in highly reduced antiviral adaptive immune responses. As a consequence, BAFFR-deficient mice showed exacerbated and fatal disease after viral infection. Mechanistically, transient lack of B cells in Baffr(-) (/) (-) animals resulted in limited lymphotoxin expression, which is critical for maintenance of CD169(+) cells. In conclusion, BAFFR signaling affects both innate and adaptive immune activation during viral infections. IMPORTANCE: Viruses cause acute and chronic infections in humans resulting in millions of deaths every year. Innate immunity is critical for the outcome of a viral infection. Innate type I interferon production can limit viral replication, while adaptive immune priming by innate immune cells induces pathogen-specific immunity with long-term protection. Here, we show that BAFFR deficiency not only perturbed B cells, but also resulted in limited CD169(+) macrophages. These macrophages are critical in amplifying viral particles to trigger type I interferon production and initiate adaptive immune priming. Consequently, BAFFR deficiency resulted in reduced enforced viral replication, limited type I interferon production, and reduced adaptive immunity compared to BAFFR-competent controls. As a result, BAFFR-deficient mice were predisposed to fatal viral infections. Thus, BAFFR expression is critical for innate immune activation and antiviral immunity.
Assuntos
Infecções por Arenaviridae/imunologia , Macrófagos/química , Macrófagos/imunologia , Receptores de Interleucina-4/deficiência , Infecções por Rhabdoviridae/imunologia , Lectina 1 Semelhante a Ig de Ligação ao Ácido Siálico/análise , Imunidade Adaptativa , Animais , Imunidade Inata , Interferon Tipo I/metabolismo , Vírus da Coriomeningite Linfocítica/imunologia , Camundongos Knockout , Transdução de Sinais , Vesiculovirus/imunologiaRESUMO
Tumor necrosis factor (TNF) is an important cytokine for host defense against pathogens but is also associated with the development of human immunopathologies. TNF blockade effectively ameliorates many chronic inflammatory conditions but compromises host immunity to tuberculosis. The search for novel, more specific human TNF blockers requires the development of a reliable animal model. We used a novel mouse model with complete replacement of the mouse TNF gene by its human ortholog (human TNF [huTNF] knock-in [KI] mice) to determine resistance to Mycobacterium bovis BCG and M. tuberculosis infections and to investigate whether TNF inhibitors in clinical use reduce host immunity. Our results show that macrophages from huTNF KI mice responded to BCG and lipopolysaccharide similarly to wild-type macrophages by NF-κB activation and cytokine production. While TNF-deficient mice rapidly succumbed to mycobacterial infection, huTNF KI mice survived, controlling the bacterial burden and activating bactericidal mechanisms. Administration of TNF-neutralizing biologics disrupted the control of mycobacterial infection in huTNF KI mice, leading to an increased bacterial burden and hyperinflammation. Thus, our findings demonstrate that human TNF can functionally replace murine TNF in vivo, providing mycobacterial resistance that could be compromised by TNF neutralization. This new animal model will be helpful for the testing of specific biologics neutralizing human TNF.
Assuntos
Modelos Animais de Doenças , Infecções por Mycobacterium/imunologia , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/imunologia , Animais , Western Blotting , Citocinas/biossíntese , Citometria de Fluxo , Técnicas de Introdução de Genes/métodos , Humanos , Macrófagos/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mycobacterium bovis/imunologia , Mycobacterium tuberculosis/imunologiaRESUMO
Bone marrow plasma cells (BMPC) are the correlate of humoral immunity, consistently releasing antibodies into the bloodstream. It remains unclear if BMPC reflect different activation environments or maturation of their precursors. Here we define human BMPC heterogeneity and track the recruitment of antibody-secreting cells (ASC) from SARS-CoV-2 vaccine immune reactions to the bone marrow (BM). Trajectories based on single-cell transcriptomes and repertoires of peripheral and BM ASC reveal sequential colonisation of BMPC compartments. In activated B cells, IL-21 suppresses CD19 expression, indicating that CD19low-BMPC are derived from follicular, while CD19high-BMPC originate from extrafollicular immune reactions. In primary immune reactions, both CD19low- and CD19high-BMPC compartments are populated. In secondary immune reactions, most BMPC are recruited to CD19high-BMPC compartments, reflecting their origin from extrafollicular reactivations of memory B cells. A pattern also observable in vaccinated-convalescent individuals and upon diphtheria/tetanus/pertussis recall-vaccination. Thus, BMPC diversity reflects the evolution of a given humoral immune response.
Assuntos
Antígenos CD19 , Medula Óssea , Interleucinas , Plasmócitos , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Células Produtoras de Anticorpos/imunologia , Antígenos CD19/imunologia , Antígenos CD19/metabolismo , Linfócitos B/imunologia , Medula Óssea/imunologia , Células da Medula Óssea/imunologia , Células da Medula Óssea/citologia , COVID-19/imunologia , COVID-19/virologia , Vacina contra Difteria, Tétano e Coqueluche/imunologia , Imunidade Humoral/imunologia , Interleucinas/imunologia , Interleucinas/metabolismo , Plasmócitos/imunologia , SARS-CoV-2/imunologia , Análise de Célula Única , VacinaçãoRESUMO
TNF displays pathogenic activities in many autoimmune disorders. However, anti-TNF therapy in multiple sclerosis patients failed because of poorly understood reasons. We used a panel of gene-targeted mice that allowed cell-type specific ablation of TNF to uncover pathogenic and protective contributions of this cytokine during autoimmune disease of the CNS. T cells and myeloid cells were found to be critical cellular sources of TNF during experimental autoimmune encephalomyelitis (EAE). TNF produced by myeloid cells accelerated the onset of disease by regulation of chemokine expression in the CNS, driving the recruitment of inflammatory cells into the target organ. TNF produced by T cells exacerbated the damage to the CNS during EAE by regulating infiltration of inflammatory myeloid cells into the CNS. In secondary lymphoid organs, TNF expressed by myeloid cells and T cells acted in synergy to dampen IL-12p40 and IL-6 production by APCs, subsequently inhibiting the development of encephalitogenic T cell responses of Th1 and Th17 types. This dual role of TNF during EAE (protective in lymphoid organs and pathogenic in CNS) suggests that global TNF blockade might be inefficient in multiple sclerosis patients because augmented autoreactive T cell development in lymphoid tissues might overwhelm the beneficial effects resulting from TNF inhibition in the CNS.