RESUMO
Although enteric helminth infections modulate immunity to mucosal pathogens, their effects on systemic microbes remain less established. Here, we observe increased mortality in mice coinfected with the enteric helminth Heligmosomoides polygyrus bakeri (Hpb) and West Nile virus (WNV). This enhanced susceptibility is associated with altered gut morphology and transit, translocation of commensal bacteria, impaired WNV-specific T cell responses, and increased virus infection in the gastrointestinal tract and central nervous system. These outcomes were due to type 2 immune skewing, because coinfection in Stat6-/- mice rescues mortality, treatment of helminth-free WNV-infected mice with interleukin (IL)-4 mirrors coinfection, and IL-4 receptor signaling in intestinal epithelial cells mediates the susceptibility phenotypes. Moreover, tuft cell-deficient mice show improved outcomes with coinfection, whereas treatment of helminth-free mice with tuft cell-derived cytokine IL-25 or ligand succinate worsens WNV disease. Thus, helminth activation of tuft cell-IL-4-receptor circuits in the gut exacerbates infection and disease of a neurotropic flavivirus.
Assuntos
Coinfecção , Nematospiroides dubius/fisiologia , Transdução de Sinais , Infecções por Strongylida/patologia , Vírus do Nilo Ocidental/fisiologia , Animais , Linfócitos T CD8-Positivos/imunologia , Modelos Animais de Doenças , Suscetibilidade a Doenças , Mucosa Intestinal/parasitologia , Mucosa Intestinal/virologia , Camundongos , Camundongos Endogâmicos C57BL , Neurônios/parasitologia , Neurônios/virologia , Receptores de Interleucina-4/metabolismo , Fator de Transcrição STAT6/genética , Índice de Gravidade de Doença , Infecções por Strongylida/parasitologiaRESUMO
CD4+ effector lymphocytes (Teff) are traditionally classified by the cytokines they produce. To determine the states that Teff cells actually adopt in frontline tissues in vivo, we applied single-cell transcriptome and chromatin analyses to colonic Teff cells in germ-free or conventional mice or in mice after challenge with a range of phenotypically biasing microbes. Unexpected subsets were marked by the expression of the interferon (IFN) signature or myeloid-specific transcripts, but transcriptome or chromatin structure could not resolve discrete clusters fitting classic helper T cell (TH) subsets. At baseline or at different times of infection, transcripts encoding cytokines or proteins commonly used as TH markers were distributed in a polarized continuum, which was functionally validated. Clones derived from single progenitors gave rise to both IFN-γ- and interleukin (IL)-17-producing cells. Most of the transcriptional variance was tied to the infecting agent, independent of the cytokines produced, and chromatin variance primarily reflected activities of activator protein (AP)-1 and IFN-regulatory factor (IRF) transcription factor (TF) families, not the canonical subset master regulators T-bet, GATA3 or RORγ.
Assuntos
Bactérias/patogenicidade , Infecções Bacterianas/microbiologia , Linfócitos T CD4-Positivos/microbiologia , Linfócitos T CD4-Positivos/parasitologia , Colo/microbiologia , Colo/parasitologia , Microbioma Gastrointestinal , Heligmosomatoidea/patogenicidade , Enteropatias Parasitárias/parasitologia , Animais , Bactérias/imunologia , Infecções Bacterianas/genética , Infecções Bacterianas/imunologia , Infecções Bacterianas/metabolismo , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Cromatina/genética , Cromatina/metabolismo , Citrobacter rodentium/imunologia , Citrobacter rodentium/patogenicidade , Colo/imunologia , Colo/metabolismo , Citocinas/genética , Citocinas/metabolismo , Modelos Animais de Doenças , Perfilação da Expressão Gênica , Heligmosomatoidea/imunologia , Interações Hospedeiro-Patógeno , Fatores Reguladores de Interferon/genética , Fatores Reguladores de Interferon/metabolismo , Enteropatias Parasitárias/genética , Enteropatias Parasitárias/imunologia , Enteropatias Parasitárias/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Nematospiroides dubius/imunologia , Nematospiroides dubius/patogenicidade , Nippostrongylus/imunologia , Nippostrongylus/patogenicidade , Fenótipo , Salmonella enterica/imunologia , Salmonella enterica/patogenicidade , Análise de Célula Única , Fator de Transcrição AP-1/genética , Fator de Transcrição AP-1/metabolismo , TranscriptomaRESUMO
Upon parasitic helminth infection, activated intestinal tuft cells secrete interleukin-25 (IL-25), which initiates a type 2 immune response during which lamina propria type 2 innate lymphoid cells (ILC2s) produce IL-13. This causes epithelial remodeling, including tuft cell hyperplasia, the function of which is unknown. We identified a cholinergic effector function of tuft cells, which are the only epithelial cells that expressed choline acetyltransferase (ChAT). During parasite infection, mice with epithelial-specific deletion of ChAT had increased worm burden, fitness, and fecal egg counts, even though type 2 immune responses were comparable. Mechanistically, IL-13-amplified tuft cells release acetylcholine (ACh) into the gut lumen. Finally, we demonstrated a direct effect of ACh on worms, which reduced their fecundity via helminth-expressed muscarinic ACh receptors. Thus, tuft cells are sentinels in naive mice, and their amplification upon helminth infection provides an additional type 2 immune response effector function.
Assuntos
Acetilcolina , Mucosa Intestinal , Animais , Acetilcolina/metabolismo , Camundongos , Mucosa Intestinal/imunologia , Mucosa Intestinal/metabolismo , Mucosa Intestinal/parasitologia , Colina O-Acetiltransferase/metabolismo , Interleucina-13/metabolismo , Interleucina-13/imunologia , Camundongos Knockout , Camundongos Endogâmicos C57BL , Helmintíase/imunologia , Helmintíase/parasitologia , Células Epiteliais/imunologia , Células Epiteliais/metabolismo , Imunidade Inata , Nematospiroides dubius/imunologia , Células em TufoRESUMO
Acidic mammalian chitinase (AMCase) is known to be induced by allergens and helminths, yet its role in immunity is unclear. Using AMCase-deficient mice, we show that AMCase deficiency reduced the number of group 2 innate lymphoid cells during allergen challenge but was not required for establishment of type 2 inflammation in the lung in response to allergens or helminths. In contrast, AMCase-deficient mice showed a profound defect in type 2 immunity following infection with the chitin-containing gastrointestinal nematodes Nippostrongylus brasiliensis and Heligmosomoides polygyrus bakeri. The impaired immunity was associated with reduced mucus production and decreased intestinal expression of the signature type 2 response genes Il13, Chil3, Retnlb, and Clca1. CD103(+) dendritic cells, which regulate T cell homing, were also reduced in mesenteric lymph nodes of infected AMCase-deficient mice. Thus, AMCase functions as a critical initiator of protective type 2 responses to intestinal nematodes but is largely dispensable for allergic responses in the lung.
Assuntos
Quitinases/imunologia , Trato Gastrointestinal/imunologia , Imunidade/imunologia , Infecções por Strongylida/imunologia , Animais , Quitinases/genética , Quitinases/metabolismo , Canais de Cloreto/genética , Canais de Cloreto/imunologia , Canais de Cloreto/metabolismo , Citometria de Fluxo , Trato Gastrointestinal/metabolismo , Trato Gastrointestinal/parasitologia , Expressão Gênica/imunologia , Hormônios Ectópicos/genética , Hormônios Ectópicos/imunologia , Hormônios Ectópicos/metabolismo , Interações Hospedeiro-Parasita/imunologia , Hipersensibilidade/genética , Hipersensibilidade/imunologia , Hipersensibilidade/metabolismo , Imunidade/genética , Peptídeos e Proteínas de Sinalização Intercelular , Interleucina-13/genética , Interleucina-13/imunologia , Interleucina-13/metabolismo , Lectinas/genética , Lectinas/imunologia , Lectinas/metabolismo , Pulmão/imunologia , Pulmão/metabolismo , Pulmão/patologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microscopia de Fluorescência , Nematospiroides dubius/imunologia , Nematospiroides dubius/fisiologia , Nippostrongylus/imunologia , Nippostrongylus/fisiologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Infecções por Strongylida/metabolismo , Infecções por Strongylida/parasitologia , beta-N-Acetil-Hexosaminidases/genética , beta-N-Acetil-Hexosaminidases/imunologia , beta-N-Acetil-Hexosaminidases/metabolismoRESUMO
Although viral infections elicit robust interferon-γ (IFN-γ) and long-lived antibody-secreting cell (ASC) responses, the roles for IFN-γ and IFN-γ-induced transcription factors (TFs) in ASC development are unclear. We showed that B cell intrinsic expression of IFN-γR and the IFN-γ-induced TF T-bet were required for T-helper 1 cell-induced differentiation of B cells into ASCs. IFN-γR signaling induced Blimp1 expression in B cells but also initiated an inflammatory gene program that, if not restrained, prevented ASC formation. T-bet did not affect Blimp1 upregulation in IFN-γ-activated B cells but instead regulated chromatin accessibility within the Ifng and Ifngr2 loci and repressed the IFN-γ-induced inflammatory gene program. Consistent with this, B cell intrinsic T-bet was required for formation of long-lived ASCs and secondary ASCs following viral, but not nematode, infection. Therefore, T-bet facilitates differentiation of IFN-γ-activated inflammatory effector B cells into ASCs in the setting of IFN-γ-, but not IL-4-, induced inflammatory responses.
Assuntos
Linfócitos B/imunologia , Interferon gama/imunologia , Receptores de Interferon/metabolismo , Proteínas com Domínio T/metabolismo , Linfócitos T Auxiliares-Indutores/imunologia , Animais , Células Produtoras de Anticorpos/imunologia , Linfócitos B/citologia , Diferenciação Celular/imunologia , Células Cultivadas , Cromatina/metabolismo , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H3N2/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Nematospiroides dubius/imunologia , Infecções por Orthomyxoviridae/imunologia , Infecções por Orthomyxoviridae/virologia , Fator 1 de Ligação ao Domínio I Regulador Positivo/biossíntese , Infecções por Strongylida/imunologia , Infecções por Strongylida/parasitologia , Proteínas com Domínio T/genética , Receptor de Interferon gamaRESUMO
The divergence of the common dendritic cell progenitor1-3 (CDP) into the conventional type 1 and type 2 dendritic cell (cDC1 and cDC2, respectively) lineages4,5 is poorly understood. Some transcription factors act in the commitment of already specified progenitors-such as BATF3, which stabilizes Irf8 autoactivation at the +32 kb Irf8 enhancer4,6-but the mechanisms controlling the initial divergence of CDPs remain unknown. Here we report the transcriptional basis of CDP divergence and describe the first requirements for pre-cDC2 specification. Genetic epistasis analysis7 suggested that Nfil3 acts upstream of Id2, Batf3 and Zeb2 in cDC1 development but did not reveal its mechanism or targets. Analysis of newly generated NFIL3 reporter mice showed extremely transient NFIL3 expression during cDC1 specification. CUT&RUN and chromatin immunoprecipitation followed by sequencing identified endogenous NFIL3 binding in the -165 kb Zeb2 enhancer8 at three sites that also bind the CCAAT-enhancer-binding proteins C/EBPα and C/EBPß. In vivo mutational analysis using CRISPR-Cas9 targeting showed that these NFIL3-C/EBP sites are functionally redundant, with C/EBPs supporting and NFIL3 repressing Zeb2 expression at these sites. A triple mutation of all three NFIL3-C/EBP sites ablated Zeb2 expression in myeloid, but not lymphoid progenitors, causing the complete loss of pre-cDC2 specification and mature cDC2 development in vivo. These mice did not generate T helper 2 (TH2) cell responses against Heligmosomoides polygyrus infection, consistent with cDC2 supporting TH2 responses to helminths9-11. Thus, CDP divergence into cDC1 or cDC2 is controlled by competition between NFIL3 and C/EBPs at the -165 kb Zeb2 enhancer.
Assuntos
Diferenciação Celular , Células Dendríticas , Elementos Facilitadores Genéticos , Mutação , Homeobox 2 de Ligação a E-box com Dedos de Zinco , Animais , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Proteínas Estimuladoras de Ligação a CCAAT/metabolismo , Diferenciação Celular/genética , Células Dendríticas/classificação , Células Dendríticas/citologia , Células Dendríticas/patologia , Elementos Facilitadores Genéticos/genética , Epistasia Genética , Proteína 2 Inibidora de Diferenciação , Linfócitos/citologia , Camundongos , Células Mieloides/citologia , Nematospiroides dubius/imunologia , Proteínas Repressoras , Células Th2/citologia , Células Th2/imunologia , Homeobox 2 de Ligação a E-box com Dedos de Zinco/genéticaRESUMO
Tissue maintenance and repair depend on the integrated activity of multiple cell types1. Whereas the contributions of epithelial2,3, immune4,5 and stromal cells6,7 in intestinal tissue integrity are well understood, the role of intrinsic neuroglia networks remains largely unknown. Here we uncover important roles of enteric glial cells (EGCs) in intestinal homeostasis, immunity and tissue repair. We demonstrate that infection of mice with Heligmosomoides polygyrus leads to enteric gliosis and the upregulation of an interferon gamma (IFNγ) gene signature. IFNγ-dependent gene modules were also induced in EGCs from patients with inflammatory bowel disease8. Single-cell transcriptomics analysis of the tunica muscularis showed that glia-specific abrogation of IFNγ signalling leads to tissue-wide activation of pro-inflammatory transcriptional programs. Furthermore, disruption of the IFNγ-EGC signalling axis enhanced the inflammatory and granulomatous response of the tunica muscularis to helminths. Mechanistically, we show that the upregulation of Cxcl10 is an early immediate response of EGCs to IFNγ signalling and provide evidence that this chemokine and the downstream amplification of IFNγ signalling in the tunica muscularis are required for a measured inflammatory response to helminths and resolution of the granulomatous pathology. Our study demonstrates that IFNγ signalling in enteric glia is central to intestinal homeostasis and reveals critical roles of the IFNγ-EGC-CXCL10 axis in immune response and tissue repair after infectious challenge.
Assuntos
Homeostase , Intestinos/imunologia , Intestinos/fisiologia , Neuroglia/imunologia , Neuroglia/fisiologia , Regeneração , Túnica Adventícia/imunologia , Túnica Adventícia/parasitologia , Animais , Quimiocina CXCL10/imunologia , Duodeno/imunologia , Duodeno/parasitologia , Duodeno/patologia , Duodeno/fisiologia , Feminino , Gliose , Homeostase/imunologia , Humanos , Inflamação/imunologia , Inflamação/patologia , Interferon gama/imunologia , Intestinos/parasitologia , Intestinos/patologia , Masculino , Camundongos , Nematospiroides dubius/imunologia , Nematospiroides dubius/patogenicidade , Transdução de Sinais/imunologia , Infecções por Strongylida/imunologia , Infecções por Strongylida/parasitologia , Infecções por Strongylida/patologiaRESUMO
Intestinal helminth infection triggers a type 2 immune response that promotes a 'weep-and sweep' response characterised by increased mucus secretion and intestinal hypermotility, which function to dislodge the worm from its intestinal habitat. Recent studies have discovered that several other pathogens cause intestinal dysmotility through major alterations to the immune and enteric nervous systems (ENS), and their interactions, within the gastrointestinal tract. However, the involvement of these systems has not been investigated for helminth infections. Eosinophils represent a key cell type recruited by the type 2 immune response and alter intestinal motility under steady-state conditions. Our study aimed to investigate whether altered intestinal motility driven by the murine hookworm, Nippostrongylus brasiliensis, infection involves eosinophils and how the ENS and smooth muscles of the gut are impacted. Eosinophil deficiency did not influence helminth-induced intestinal hypermotility and hypermotility did not involve gross structural or functional changes to the ENS. Hypermotility was instead associated with a dramatic increase in smooth muscle thickness and contractility, an observation that extended to another rodent nematode, Heligmosomoides polygyrus. In summary our data indicate that, in contrast to other pathogens, helminth-induced intestinal hypermotility is driven by largely by myogenic, rather than neurogenic, alterations with such changes occurring independently of eosinophils. (<300 words).
Assuntos
Sistema Nervoso Entérico , Eosinófilos , Motilidade Gastrointestinal , Músculo Liso , Nippostrongylus , Animais , Camundongos , Eosinófilos/imunologia , Músculo Liso/parasitologia , Sistema Nervoso Entérico/parasitologia , Sistema Nervoso Entérico/imunologia , Motilidade Gastrointestinal/fisiologia , Nematospiroides dubius/fisiologia , Nematospiroides dubius/imunologia , Infecções por Strongylida/imunologia , Infecções por Strongylida/parasitologia , Enteropatias Parasitárias/imunologia , Enteropatias Parasitárias/parasitologia , Helmintíase/imunologia , Helmintíase/parasitologia , Neurônios/parasitologia , Neurônios/metabolismo , Camundongos Endogâmicos C57BLRESUMO
Infection by helminth parasites is associated with amelioration of allergic reactivity, but mechanistic insights into this association are lacking. Products secreted by the mouse parasite Heligmosomoides polygyrus suppress type 2 (allergic) immune responses through interference in the interleukin-33 (IL-33) pathway. Here, we identified H. polygyrus Alarmin Release Inhibitor (HpARI), an IL-33-suppressive 26-kDa protein, containing three predicted complement control protein (CCP) modules. In vivo, recombinant HpARI abrogated IL-33, group 2 innate lymphoid cell (ILC2) and eosinophilic responses to Alternaria allergen administration, and diminished eosinophilic responses to Nippostrongylus brasiliensis, increasing parasite burden. HpARI bound directly to both mouse and human IL-33 (in the cytokine's activated state) and also to nuclear DNA via its N-terminal CCP module pair (CCP1/2), tethering active IL-33 within necrotic cells, preventing its release, and forestalling initiation of type 2 allergic responses. Thus, HpARI employs a novel molecular strategy to suppress type 2 immunity in both infection and allergy.
Assuntos
Proteínas de Helminto/imunologia , Interleucina-33/imunologia , Nematospiroides dubius/imunologia , Infecções por Strongylida/imunologia , Alérgenos/imunologia , Alternaria/imunologia , Sequência de Aminoácidos , Animais , Western Blotting , Eosinófilos/imunologia , Proteínas de Helminto/genética , Proteínas de Helminto/metabolismo , Interações Hospedeiro-Parasita/imunologia , Humanos , Imunidade Inata/imunologia , Proteína 1 Semelhante a Receptor de Interleucina-1 , Interleucina-33/genética , Interleucina-33/metabolismo , Linfócitos/imunologia , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Nematospiroides dubius/genética , Nematospiroides dubius/metabolismo , Ligação Proteica/imunologia , Receptores de Interleucina/imunologia , Receptores de Interleucina/metabolismo , Homologia de Sequência de Aminoácidos , Infecções por Strongylida/metabolismo , Infecções por Strongylida/parasitologiaRESUMO
Gastro-intestinal helminth infections trigger the release of interleukin-33 (IL-33), which induces type-2 helper T cells (Th2 cells) at the site of infection to produce IL-13, thereby contributing to host resistance in a T cell receptor (TCR)-independent manner. Here, we show that, as a prerequisite for IL-33-induced IL-13 secretion, Th2 cells required the expression of the epidermal growth factor receptor (EGFR) and of its ligand, amphiregulin, for the formation of a signaling complex between T1/ST2 (the IL-33R) and EGFR. This shared signaling complex allowed IL-33 to induce the EGFR-mediated activation of the MAP-kinase signaling pathway and consequently the expression of IL-13. Lack of EGFR expression on T cells abrogated IL-13 expression in infected tissues and impaired host resistance. EGFR expression on Th2 cells was TCR-signaling dependent, and therefore, our data reveal a mechanism by which antigen presentation controls the innate effector function of Th2 cells at the site of inflammation.
Assuntos
Receptores ErbB/imunologia , Interleucina-13/imunologia , Interleucina-33/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Células Th2/imunologia , Anfirregulina/imunologia , Anfirregulina/metabolismo , Animais , Linhagem Celular , Células Cultivadas , Receptores ErbB/genética , Receptores ErbB/metabolismo , Expressão Gênica/genética , Expressão Gênica/imunologia , Perfilação da Expressão Gênica/métodos , Células HEK293 , Humanos , Interleucina-13/genética , Interleucina-13/metabolismo , Interleucina-33/genética , Interleucina-33/metabolismo , Sistema de Sinalização das MAP Quinases/imunologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Nematospiroides dubius/imunologia , Nematospiroides dubius/fisiologia , Nocardia/imunologia , Nocardia/fisiologia , Nocardiose/imunologia , Nocardiose/metabolismo , Nocardiose/microbiologia , Receptores de Antígenos de Linfócitos T/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Infecções por Strongylida/imunologia , Infecções por Strongylida/metabolismo , Infecções por Strongylida/parasitologia , Células Th2/metabolismoRESUMO
Gastrointestinal helminths are a major health threat worldwide. Alternatively activated macrophages (AAMs) have been shown to contribute to host protection during secondary helminth infections. AAMs express effector molecules that depend on activation of the IL-4- or IL-13-induced transcription factor signal transducer and activator of transcription 6 (STAT6). However, the specific role of STAT6-regulated genes like Arginase-1 (Arg1) from AAMs or STAT6-regulated genes in other cell types for host protection remains unclear. To address this point, we generated mice expressing STAT6 only in macrophages (Mac-STAT6 mouse). In the model of Heligmosomoides polygyrus bakeri (Hpb) infection, Mac-STAT6 mice could not trap larvae in the submucosa of the small intestine after secondary infection. Further, mice lacking Arg1 in hematopoietic and endothelial cells were still protected from secondary Hpb infection. On the other hand, specific deletion of IL-4/IL-13 in T cells blunted AAM polarization, activation of intestinal epithelial cells (IECs) and protective immunity. Deletion of IL-4Rα on IEC also caused loss of larval trapping while AAM polarization remained intact. These results show that Th2-dependent and STAT6-regulated genes in IECs are required and AAMs are not sufficient for protection against secondary Hpb infection by mechanisms that remain to be investigated.
Assuntos
Coinfecção , Nematospiroides dubius , Infecções por Strongylida , Camundongos , Animais , Nematospiroides dubius/metabolismo , Camundongos Knockout , Interleucina-4/genética , Interleucina-4/metabolismo , Interleucina-13/metabolismo , Larva/metabolismo , Células Endoteliais/metabolismo , Células Epiteliais/metabolismo , Fator de Transcrição STAT6/genética , Fator de Transcrição STAT6/metabolismo , Infecções por Strongylida/genéticaRESUMO
HpARI is an immunomodulatory protein secreted by the intestinal nematode Heligmosomoides polygyrus bakeri, which binds and blocks IL-33. Here, we find that the H. polygyrus bakeri genome contains three HpARI family members and that these have different effects on IL-33-dependent responses in vitro and in vivo, with HpARI1+2 suppressing and HpARI3 amplifying these responses. All HpARIs have sub-nanomolar affinity for mouse IL-33; however, HpARI3 does not block IL-33-ST2 interactions. Instead, HpARI3 stabilizes IL-33, increasing the half-life of the cytokine and amplifying responses to it in vivo. Together, these data show that H. polygyrus bakeri secretes a family of HpARI proteins with both overlapping and distinct functions, comprising a complex immunomodulatory arsenal of host-targeted proteins.
Assuntos
Nematospiroides dubius , Infecções por Strongylida , Camundongos , Animais , Interleucina-33/genética , Citocinas , Imunomodulação , ImunidadeRESUMO
Parasitic nematodes infect more than 1 billion people in the global south. The development of effective antihelminthic vaccines is a crucial tool for their future elimination. Protective immune responses to nematodes depend on Gata3+ Th2 cells, which can also be induced by nematode-released products. Whether these nematode products induce antigen-specific long-lived memory T cells and thereby confer protection against a challenge infection is not known yet. Hence, we set out to characterize the formation of memory Th2 cells induced by immunization with Heligmosomoides polygyrus excretory-secretory (HES) products, infection-induced versus immunization-induced recall responses to a challenge infection, and whether HES-induced memory T cells show protective properties following adoptive transfer. Our results show that 8 weeks postimmunization, HES induces long-lived functional memory Th2 cells at the site of immunization in the peritoneal cavity. Following a H. polygyrus challenge infection, HES-immunized mice display MHC-II-dependent antigen-specific Th2 cytokine responses in the gut-draining lymph nodes, comparable to those induced by a prior natural infection. Moreover, adoptive transfer of sorted memory CD4+ T cells from HES-immunized donors reduces female worm fecundity following a challenge H. polygyrus infection in recipient mice, highlighting a protective role for immunization-induced memory T cells.
Assuntos
Nematoides , Nematospiroides dubius , Infecções por Strongylida , Camundongos , Feminino , Animais , Células Th2 , Imunização , Citocinas , Vacinação , Camundongos Endogâmicos BALB CRESUMO
Increased permeability of the intestinal epithelial layer is linked to the pathogenesis and perpetuation of a wide range of intestinal and extra-intestinal diseases. Infecting humans with controlled doses of helminths, such as human hookworm (termed hookworm therapy), is proposed as a treatment for many of the same diseases. Helminths induce immunoregulatory changes in their host which could decrease epithelial permeability, which is highlighted as a potential mechanism through which helminths treat disease. Despite this, the influence of a chronic helminth infection on epithelial permeability remains unclear. This study uses the chronically infecting intestinal helminth Heligmosomoides polygyrus to reveal alterations in the expression of intestinal tight junction proteins and epithelial permeability during the infection course. In the acute infection phase (1 week postinfection), an increase in intestinal epithelial permeability is observed. Consistent with this finding, jejunal claudin-2 is upregulated and tricellulin is downregulated. By contrast, in the chronic infection phase (6 weeks postinfection), colonic claudin-1 is upregulated and epithelial permeability decreases. Importantly, this study also investigates changes in epithelial permeability in a small human cohort experimentally challenged with the human hookworm, Necator americanus. It demonstrates a trend toward small intestinal permeability increasing in the acute infection phase (8 weeks postinfection), and colonic and whole gut permeability decreasing in the chronic infection phase (24 weeks postinfection), suggesting a conserved epithelial response between humans and mice. In summary, our findings demonstrate dynamic changes in epithelial permeability during a chronic helminth infection and provide another plausible mechanism by which chronic helminth infections could be utilized to treat disease.
Assuntos
Mucosa Intestinal , Permeabilidade , Animais , Humanos , Mucosa Intestinal/parasitologia , Mucosa Intestinal/metabolismo , Mucosa Intestinal/imunologia , Doença Crônica , Nematospiroides dubius/imunologia , Camundongos , Necator americanus , Enteropatias Parasitárias/imunologia , Junções Íntimas/metabolismo , Proteínas de Junções Íntimas/metabolismo , Intestino Delgado/parasitologia , Intestino Delgado/imunologia , Feminino , Camundongos Endogâmicos C57BL , Masculino , Helmintíase/imunologia , Helmintíase/parasitologia , Necatoríase/imunologia , Proteína 2 com Domínio MARVEL/metabolismoRESUMO
Although cognate encounters between antigen-bearing dendritic cells (DCs) that express the chemokine receptor CCR7 and CCR7(+) naive T cells take place in the T cell zone of lymph nodes, it is unknown whether the colocalization of DCs and T cells in the T cell area is required for the generation of effector cells. Here we found that after infection with an intestinal nematode, antigen-bearing DCs and CD4(+) T cells upregulated the chemokine receptor CXCR5 and localized together outside the T cell zone by a mechanism dependent on the chemokine CXCL13, B cells and lymphotoxin. Notably, lymphotoxin-expressing B cells, CXCR5-expressing DCs and T cells, and CXCL13 were also necessary for development of interleukin 4 (IL-4)-producing type 2 helper T cells (T(H)2 cells), which suggests that T(H)2 differentiation can initiate outside the T cell zone.
Assuntos
Linfócitos B/imunologia , Células Dendríticas/imunologia , Linfotoxina-alfa/imunologia , Receptores CXCR5/imunologia , Infecções por Strongylida/imunologia , Células Th2/imunologia , Animais , Quimiocina CXCL13/imunologia , Interleucina-4/imunologia , Ativação Linfocitária/imunologia , Linfotoxina-alfa/biossíntese , Linfotoxina-alfa/genética , Camundongos , Camundongos Endogâmicos C57BL , Nematospiroides dubius/imunologiaRESUMO
BACKGROUND: Respiratory syncytial virus (RSV) infection in infants is a major cause of viral bronchiolitis and hospitalisation. We have previously shown in a murine model that ongoing infection with the gut helminth Heligmosomoides polygyrus protects against RSV infection through type I interferon (IFN-I) dependent reduction of viral load. Yet, the cellular basis for this protection has remained elusive. Given that recruitment of mononuclear phagocytes to the lung is critical for early RSV infection control, we assessed their role in this coinfection model. METHODS: Mice were infected by oral gavage with H. polygyrus. Myeloid immune cell populations were assessed by flow cytometry in lung, blood and bone marrow throughout infection and after secondary infection with RSV. Monocyte numbers were depleted by anti-CCR2 antibody or increased by intravenous transfer of enriched monocytes. RESULTS: H. polygyrus infection induces bone marrow monopoiesis, increasing circulatory monocytes and lung mononuclear phagocytes in a IFN-I signalling dependent manner. This expansion causes enhanced lung mononuclear phagocyte counts early in RSV infection that may contribute to the reduction of RSV load. Depletion or supplementation of circulatory monocytes prior to RSV infection confirms that these are both necessary and sufficient for helminth induced antiviral protection. CONCLUSIONS: H. polygyrus infection induces systemic monocytosis contributing to elevated mononuclear phagocyte numbers in the lung. These cells are central to an anti-viral effect that reduces the peak viral load in RSV infection. Treatments to promote or modulate these cells may provide novel paths to control RSV infection in high risk individuals.
Assuntos
Modelos Animais de Doenças , Monócitos , Infecções por Vírus Respiratório Sincicial , Carga Viral , Animais , Infecções por Vírus Respiratório Sincicial/imunologia , Camundongos , Monócitos/imunologia , Nematospiroides dubius/imunologia , Pulmão/imunologia , Pulmão/virologia , Infecções por Strongylida/imunologia , Vírus Sinciciais Respiratórios/imunologia , Interferon Tipo I/metabolismoRESUMO
Intestinal helminths are potent regulators of their host's immune system and can ameliorate inflammatory diseases such as allergic asthma. In the present study we have assessed whether this anti-inflammatory activity was purely intrinsic to helminths, or whether it also involved crosstalk with the local microbiota. We report that chronic infection with the murine helminth Heligmosomoides polygyrus bakeri (Hpb) altered the intestinal habitat, allowing increased short chain fatty acid (SCFA) production. Transfer of the Hpb-modified microbiota alone was sufficient to mediate protection against allergic asthma. The helminth-induced anti-inflammatory cytokine secretion and regulatory T cell suppressor activity that mediated the protection required the G protein-coupled receptor (GPR)-41. A similar alteration in the metabolic potential of intestinal bacterial communities was observed with diverse parasitic and host species, suggesting that this represents an evolutionary conserved mechanism of host-microbe-helminth interactions.
Assuntos
Microbioma Gastrointestinal/imunologia , Helmintos/imunologia , Hipersensibilidade/imunologia , Inflamação/imunologia , Inflamação/parasitologia , Mucosa Intestinal/imunologia , Mucosa Intestinal/microbiologia , Adulto , Idoso , Animais , Asma/imunologia , Asma/microbiologia , Asma/parasitologia , Citocinas/imunologia , Ácidos Graxos/imunologia , Feminino , Humanos , Hipersensibilidade/microbiologia , Hipersensibilidade/parasitologia , Inflamação/microbiologia , Mucosa Intestinal/parasitologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Nematospiroides dubius/imunologia , Receptores Acoplados a Proteínas G/imunologia , Infecções por Strongylida/imunologia , Infecções por Strongylida/microbiologia , Infecções por Strongylida/parasitologiaRESUMO
More than 2 billion people worldwide are infected with helminths. Thus, it is possible for individuals to experience concomitant infection with helminth and intracellular microbes. Although the helminth-induced type 2 response can suppress type 1 proinflammatory responses required for the immunity against intracellular pathogens in the context of a coinfection, conflicting evidence suggest that helminth infection can enhance antimicrobial immunity. Using a coinfection model with the intestinal helminth Heligmosomoides polygyrus followed by infection with Toxoplasma gondii in Mus Musculus, we showed that the complex and dynamic effect of helminth infection is highly suppressive during the innate phase (days 0-3) of T. gondii infection and less stringent during the acute phase (d10). Helminth coinfection had a strong suppressive effect on the neutrophil, monocytic, and early IFN-γ/IL-12 responses. The IFN-γ response was later restored by compensatory production from T cells despite decreased effector differentiation of T. gondii-specific CD8 T cells. In accordance with the attenuated IFN-γ response, parasite loads were elevated during the acute phase (d10) of T. gondii infection but were transiently controlled by the compensatory T cell response. Unexpectedly, 40% of helminth-coinfected mice exhibited a sustained weight loss phenotype during the postacute phase (d14-18) that was not associated with T. gondii outgrowth, indicating that coinfection led to decreased disease tolerance during T. gondii infection. Our work uncovers the dynamic nature of the helminth immunomodulatory effects on concomitant infections or immune responses and unveils a loss of disease tolerance phenotype triggered by coinfection with intestinal helminth.
Assuntos
Coinfecção , Nematospiroides dubius , Toxoplasma , Toxoplasmose , Animais , Camundongos , Tolerância ImunológicaRESUMO
Epithelial surfaces form critical barriers to the outside world and are continuously renewed by adult stem cells1. Whereas dynamics of epithelial stem cells during homeostasis are increasingly well understood, how stem cells are redirected from a tissue-maintenance program to initiate repair after injury remains unclear. Here we examined infection by Heligmosomoides polygyrus, a co-evolved pathosymbiont of mice, to assess the epithelial response to disruption of the mucosal barrier. H. polygyrus disrupts tissue integrity by penetrating the duodenal mucosa, where it develops while surrounded by a multicellular granulomatous infiltrate2. Crypts overlying larvae-associated granulomas did not express intestinal stem cell markers, including Lgr53, in spite of continued epithelial proliferation. Granuloma-associated Lgr5- crypt epithelium activated an interferon-gamma (IFN-γ)-dependent transcriptional program, highlighted by Sca-1 expression, and IFN-γ-producing immune cells were found in granulomas. A similar epithelial response accompanied systemic activation of immune cells, intestinal irradiation, or ablation of Lgr5+ intestinal stem cells. When cultured in vitro, granuloma-associated crypt cells formed spheroids similar to those formed by fetal epithelium, and a sub-population of H. polygyrus-induced cells activated a fetal-like transcriptional program, demonstrating that adult intestinal tissues can repurpose aspects of fetal development. Therefore, re-initiation of the developmental program represents a fundamental mechanism by which the intestinal crypt can remodel itself to sustain function after injury.
Assuntos
Feto/citologia , Helmintos/fisiologia , Intestinos/citologia , Parasitos/fisiologia , Nicho de Células-Tronco , Células-Tronco/citologia , Animais , Antígenos Ly/biossíntese , Células Epiteliais/citologia , Feminino , Feto/metabolismo , Interferon gama/imunologia , Masculino , Proteínas de Membrana/biossíntese , Camundongos , Camundongos Endogâmicos C57BL , Nematospiroides dubius/fisiologia , Receptores Acoplados a Proteínas G/metabolismo , Infecções por Strongylida/parasitologiaRESUMO
Sheep haemonchosis is a disease that causes serious losses in livestock production, particularly with the increase of cases of anthelmintic resistance around the world. This justifies the urgent need of alternative solutions. The aim of this study was to determine the chemical profile, in vitro, and, in vivo, anthelmintic properties of Thymus capitatus essential oil. To evaluate the, in vitro, anthelmintic activity of the T. capitatus EO on Haemonchus contortus, two tests were used: egg hatch assay (EHA) and adult worm motility (AWM) assay. The nematicidal effect of this oil was evaluated, in vivo, in mice infected artificially with Heligmosomoides polygyrus using faecal egg count reduction (FECR) and total worm count reduction (TWCR). Chromatographic characterization of T.capitatus composition using gas chromatography coupled to mass spectrometry (GC-MS) demonstrated the presence of carvacrol (81.16%), as the major constituents. The IC50 values obtained was 1.9 mg/mL in the EHT. In the AWM assay; T. capitatus essential oil achieved 70.8% inhibition at 1 mg/mL after 8 h incubation. The in vivo, evaluation on H. polygyrus revealed a significant nematicidal effect 7 days post-treatment by inducing 49.5% FECR and 64.5% TWCR, using the highest dose (1600 mg/kg). The results of present study, demonstrate that T.capitatus EO possess a significant anthelmintic properties. Furthermore, it could be an alternative source of anthelmintic agents against gastrointestinal infections caused by H. contortus.