RESUMO
Th9 cells are a new subpopulation of CD4+ T helper cells, characterized by the expression of IL-9 that have been involved in type 2 immune responses, antitumor responses and autoimmune diseases. Here, we describe two different parasitic models frequently maintained in the laboratory where Th9 cells or IL-9 (the cytokine produced by Th9 cells) has been shown to play critical roles in pathogen clearance and immune response activation: the nematode Nippostrongylus brasiliensis and the trematode Schistosoma mansoni.
Assuntos
Inflamação/metabolismo , Animais , Helmintos/imunologia , Helmintos/metabolismo , Interleucina-9/metabolismo , Nippostrongylus/imunologia , Nippostrongylus/metabolismo , Schistosoma mansoni/imunologia , Schistosoma mansoni/metabolismoRESUMO
Infections with helminth parasites are endemic in the developing world and are a target for intervention with new therapies. Macrophage migration inhibitory factor (MIF) is a cytokine with pleiotropic effects in inflammation and immune responses. We investigated the role of MIF in a naturally cleared model of helminth infection in rodents, Nippostrongylus brasiliensis. At day 7 postinfection, MIF-deficient (MIF-/-) mice had reduced parasite burden and mounted an enhanced type 2 immune response (Th2), including increased Gata3 expression and interleukin-13 (IL-13) production in the mesenteric lymph nodes (MLNs). Bone marrow reconstitution demonstrated that MIF produced from hematopoietic cells was crucial and Rag1-/- reconstitution provided direct evidence that MIF-/- CD4+ T cells were responsible for the augmented parasite clearance. MIF-/- CD4+ T cells produced less IL-6 postinfection, which correlated with enhanced Th2 responses. MIF-/- CD4+ T cells exhibited lower nuclear factor-κB activation, potentially explaining the reduction in IL-6. Finally, we demonstrated enhanced clearance of the parasite and Th2 response in wild-type mice treated with the MIF tautomerase inhibitor, sulforaphane, a compound found naturally found in cruciferous vegetables. These results are the first to describe the importance of the tautomerase enzyme activity in MIF function in N. brasiliensis infection.
Assuntos
Fator de Transcrição GATA3/metabolismo , Interleucina-13/metabolismo , Oxirredutases Intramoleculares/metabolismo , Fatores Inibidores da Migração de Macrófagos/metabolismo , Macrófagos/imunologia , Nippostrongylus/imunologia , Infecções por Strongylida/imunologia , Células Th2/imunologia , Animais , Antígenos de Helmintos/imunologia , Células Cultivadas , Feminino , Fator de Transcrição GATA3/genética , Imunidade , Oxirredutases Intramoleculares/antagonistas & inibidores , Oxirredutases Intramoleculares/genética , Isotiocianatos/uso terapêutico , Fatores Inibidores da Migração de Macrófagos/genética , Macrófagos/parasitologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Carga Parasitária , Infecções por Strongylida/tratamento farmacológico , Sulfóxidos , Células Th2/efeitos dos fármacos , Células Th2/parasitologiaRESUMO
Despite increased appreciation for the role of nicotinic receptors in the modulation of and response to inflammation, the contribution of muscarinic receptors to mucosal homeostasis, clearance of enteric pathogens, and modulation of immune cell function remains relatively undefined. Uninfected and Nippostrongylus brasiliensis-infected wild-type and type 3 muscarinic receptor (M3R)-deficient (Chrm3(-/-)) mice were studied to determine the contribution of M3R to mucosal homeostasis as well as host defense against the TH2-eliciting enteric nematode N. brasiliensis Intestinal permeability and expression of TH1/TH17 cytokines were increased in uninfected Chrm3(-/-) small intestine. Notably, in Chrm3(-/-) mice infected with N. brasiliensis, small intestinal upregulation of TH2 cytokines was attenuated and nematode clearance was delayed. In Chrm3(-/-) mice, TH2-dependent changes in small intestinal function including smooth muscle hypercontractility, increased epithelial permeability, decreased epithelial secretion and absorption, and goblet cell expansion were absent despite N. brasiliensis infection. These findings identify an important role for M3R in host defense and clearance of N. brasiliensis, and support the expanding role of cholinergic muscarinic receptors in maintaining mucosal homeostasis.
Assuntos
Citocinas/metabolismo , Imunidade nas Mucosas , Mucosa Intestinal/metabolismo , Intestino Delgado/metabolismo , Nippostrongylus/patogenicidade , Receptor Muscarínico M3/metabolismo , Infecções por Strongylida/metabolismo , Células Th2/metabolismo , Animais , Células Cultivadas , Citocinas/imunologia , Modelos Animais de Doenças , Predisposição Genética para Doença , Homeostase , Interações Hospedeiro-Patógeno , Mucosa Intestinal/imunologia , Mucosa Intestinal/parasitologia , Intestino Delgado/imunologia , Intestino Delgado/parasitologia , Ativação de Macrófagos , Macrófagos/imunologia , Macrófagos/metabolismo , Macrófagos/parasitologia , Camundongos da Linhagem 129 , Camundongos Endogâmicos C57BL , Camundongos Knockout , Nippostrongylus/imunologia , Fenótipo , Receptor Muscarínico M3/deficiência , Receptor Muscarínico M3/genética , Infecções por Strongylida/genética , Infecções por Strongylida/imunologia , Infecções por Strongylida/parasitologia , Células Th2/imunologia , Células Th2/parasitologia , Fatores de TempoRESUMO
The plasticity of macrophages is evident in helminthic parasite infections, providing protection from inflammation. Previously we demonstrated that the micronutrient selenium induces a phenotypic switch in macrophage activation from a classically activated (pro-inflammatory; M1/CAM) toward an alternatively activated (anti-inflammatory; M2/AAM) phenotype, where cyclooxygenase (COX)-dependent cyclopentenone prostaglandin J2 (15d-PGJ2) plays a key role. Here, we hypothesize that dietary selenium modulates macrophage polarization toward an AAM phenotype to assist in the increasing clearance of adult Nippostrongylus brasiliensis, a gastrointestinal nematode parasite. Mice on a selenium-adequate (0.08 ppm) diet significantly augmented intestinal AAM presence while decreasing adult worms and fecal egg production when compared with infection of mice on selenium-deficient (<0.01 ppm) diet. Further increase in dietary selenium to supraphysiological levels (0.4 ppm) had very little or no impact on worm expulsion. Normal adult worm clearance and enhanced AAM marker expression were observed in the selenium-supplemented Trsp(fl/fl)Cre(WT) mice that express selenoproteins driven by tRNA(Sec) (Trsp), whereas N. brasiliensis-infected Trsp(fl/fl)Cre(LysM) selenium-supplemented mice showed a decreased clearance, with lowered intestinal expression of several AAM markers. Inhibition of the COX pathway with indomethacin resulted in delayed worm expulsion in selenium-adequate mice. This was rescued with 15d-PGJ2, which partially recapitulated the effect of selenium supplementation on fecal egg output in addition to increasing markers of AAMs in the small intestine. Antagonism of PPARγ blocked the effect of selenium. These results suggest that optimal expression of selenoproteins and selenium-dependent production of COX-derived endogenous prostanoids, such as Δ(12)-PGJ2 and 15d-PGJ2, may regulate AAM activation to enhance anti-helminthic parasite responses.
Assuntos
Regulação da Expressão Gênica/imunologia , Ativação de Macrófagos , Macrófagos/imunologia , Nippostrongylus/imunologia , Selenoproteínas/imunologia , Infecções por Strongylida/imunologia , Animais , Suplementos Nutricionais , Macrófagos/parasitologia , Macrófagos/patologia , Masculino , Camundongos , Prostaglandina D2/análogos & derivados , Prostaglandina D2/imunologia , Selênio/farmacologia , Infecções por Strongylida/tratamento farmacológicoRESUMO
Mounting an antibody response capable of discriminating amongst and appropriately targeting different parasites is crucial in host defence. However, cross-reactive antibodies that recognize (bind to) multiple parasite species are well documented. We aimed to determine if a higher inoculating dose of one species, and thus exposure to larger amounts of antigen over a longer period of time, would fine-tune responses to that species and reduce cross-reactivity. Using the Plasmodium chabaudi chabaudi (Pcc)-Nippostrongylus brasiliensis (Nb) co-infection model in BALB/c mice, in which we previously documented cross-reactive antibodies, we manipulated the inoculating dose of Pcc across 4 orders of magnitude. We investigated antigen-specific and cross-reactive antibody responses against crude and defined recombinant antigens by enzyme linked immunosorbent assay, Western blot and antibody depletion assays. Contrary to our hypothesis that increasing exposure to Pcc would reduce cross-reactivity to Nb, we found evidence for increased avidity of a subpopulation of antibodies that recognized shared antigens. Western blot indicated proteins of apparent monomer molecular mass 28 and 98 kDa in both Nb and Pcc antigen preparations and also an Nb protein of similar size to recombinant Pcc antigen, merozoite surface protein-1(19). The implications of antibodies binding antigen from such phylogenetically distinct parasites are discussed.
Assuntos
Anticorpos Anti-Helmínticos/imunologia , Antígenos de Protozoários/imunologia , Nippostrongylus/imunologia , Plasmodium chabaudi/imunologia , Análise de Variância , Animais , Afinidade de Anticorpos , Coinfecção , Reações Cruzadas , Epitopos/imunologia , Feminino , Imunoglobulina G/imunologia , Malária/complicações , Malária/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Murinae , Organismos Livres de Patógenos Específicos , Baço/imunologia , Infecções por Strongylida/complicações , Infecções por Strongylida/imunologiaRESUMO
BACKGROUND: The impact of exposure to multiple pathogens concurrently or consecutively on immune function is unclear. Here, immune responses induced by combinations of the bacterium Salmonella Typhimurium (STm) and the helminth Nippostrongylus brasiliensis (Nb), which causes a murine hookworm infection and an experimental porin protein vaccine against STm, were examined. METHODOLOGY/PRINCIPAL FINDINGS: Mice infected with both STm and Nb induced similar numbers of Th1 and Th2 lymphocytes compared with singly infected mice, as determined by flow cytometry, although lower levels of secreted Th2, but not Th1 cytokines were detected by ELISA after re-stimulation of splenocytes. Furthermore, the density of FoxP3+ T cells in the T zone of co-infected mice was lower compared to mice that only received Nb, but was greater than those that received STm. This reflected the intermediate levels of IL-10 detected from splenocytes. Co-infection compromised clearance of both pathogens, with worms still detectable in mice weeks after they were cleared in the control group. Despite altered control of bacterial and helminth colonization in co-infected mice, robust extrafollicular Th1 and Th2-reflecting immunoglobulin-switching profiles were detected, with IgG2a, IgG1 and IgE plasma cells all detected in parallel. Whilst extrafollicular antibody responses were maintained in the first weeks after co-infection, the GC response was less than that in mice infected with Nb only. Nb infection resulted in some abrogation of the longer-term development of anti-STm IgG responses. This suggested that prior Nb infection may modulate the induction of protective antibody responses to vaccination. To assess this we immunized mice with porins, which confer protection in an antibody-dependent manner, before challenging with STm. Mice that had resolved a Nb infection prior to immunization induced less anti-porin IgG and had compromised protection against infection. CONCLUSION: These findings demonstrate that co-infection can radically alter the development of protective immunity during natural infection and in response to immunization.
Assuntos
Nippostrongylus/imunologia , Vacinas contra Salmonella/imunologia , Salmonella typhimurium/imunologia , Infecções por Strongylida/imunologia , Animais , Anticorpos Antibacterianos/sangue , Anticorpos Anti-Helmínticos/sangue , Coinfecção/imunologia , Citocinas/biossíntese , Imunização , Switching de Imunoglobulina , Imunoglobulina G/sangue , Camundongos , Camundongos Endogâmicos BALB C , Linfócitos T/imunologiaRESUMO
Immunity to Nippostrongylus brasiliensis reinfection requires pulmonary CD4⺠T-cell responses. We examined whether secondary lymphoid recruited or pre-existing lung CD4⺠T-cell populations coordinated this immunity. To do this, we blocked T-cell egress from lymph nodes using Fingolimod (FTY720). This impaired host ability to resolve a primary infection but did not change effectiveness of recall immunity. Associated with this effective recall immunity was the expansion and T helper type 2 polarization of a pre-existing pulmonary CD4⺠T-cell population. LTßR-Ig (lymphotoxin beta-receptor fusion protein)-mediated disruption of stromal cell organization of immune cells did not disrupt this recall immunity, suggesting that protection was mediated by a pulmonary interstitial residing CD4⺠T-cell population. Adoptive transfer of N. brasiliensis-experienced pulmonary CD4⺠T cells from FTY720-treated wild-type or T-cell interleukin (IL)-4Rα-deficient mice demonstrated protection to be IL-4Rα dependent. These results show that pre-existing CD4⺠T cells can drive effective recall immunity to N. brasiliensis infection independently of T-cell recruitment from secondary lymphoid organs.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Memória Imunológica , Subunidade alfa de Receptor de Interleucina-4/metabolismo , Pulmão/imunologia , Pulmão/metabolismo , Nippostrongylus/imunologia , Infecções por Strongylida/imunologia , Infecções por Strongylida/metabolismo , Animais , Linfócitos T CD4-Positivos/metabolismo , Movimento Celular/genética , Movimento Celular/imunologia , Modelos Animais de Doenças , Expressão Gênica , Subunidade alfa de Receptor de Interleucina-4/genética , Pulmão/parasitologia , Linfonodos/imunologia , Linfonodos/metabolismo , Camundongos , Camundongos Knockout , Infecções por Strongylida/genética , Infecções por Strongylida/parasitologiaRESUMO
In this study, B cell function in protective T(H)2 immunity against N. brasiliensis infection was investigated. Protection against secondary infection depended on IL-4Rα and IL-13; but not IL-4. Protection did not associate with parasite specific antibody responses. Re-infection of B cell-specific IL-4Rαâ»/â» mice resulted in increased worm burdens compared to control mice, despite their equivalent capacity to control primary infection. Impaired protection correlated with reduced lymphocyte IL-13 production and B cell MHC class II and CD86 surface expression. Adoptive transfer of in vivo N. brasiliensis primed IL-4Rα expressing B cells into naïve BALB/c mice, but not IL-4Rα or IL-13 deficient B cells, conferred protection against primary N. brasiliensis infection. This protection required MHC class II compatibility on B cells suggesting cognate interactions by B cells with CD4⺠T cells were important to co-ordinate immunity. Furthermore, the rapid nature of these protective effects by B cells suggested non-BCR mediated mechanisms, such as via Toll Like Receptors, was involved, and this was supported by transfer experiments using antigen pulsed Myd88â»/â» B cells. These data suggest TLR dependent antigen processing by IL-4Rα-responsive B cells producing IL-13 contribute significantly to CD4⺠T cell-mediated protective immunity against N. brasiliensis infection.
Assuntos
Apresentação de Antígeno , Linfócitos B/imunologia , Imunidade Celular , Nippostrongylus/imunologia , Receptores de Superfície Celular/imunologia , Infecções por Strongylida/imunologia , Células Th2/imunologia , Animais , Linfócitos B/patologia , Antígeno B7-2/genética , Antígeno B7-2/imunologia , Antígenos de Histocompatibilidade Classe II/genética , Antígenos de Histocompatibilidade Classe II/imunologia , Interleucina-13/genética , Interleucina-13/imunologia , Camundongos Endogâmicos BALB C , Camundongos Knockout , Fator 88 de Diferenciação Mieloide/genética , Fator 88 de Diferenciação Mieloide/imunologia , Receptores de Superfície Celular/genética , Infecções por Strongylida/genética , Infecções por Strongylida/patologia , Células Th2/patologia , Receptores Toll-Like/genética , Receptores Toll-Like/imunologiaRESUMO
BACKGROUND: Nematode secreted haemoglobins have unusually high affinity for oxygen and possess nitric oxide deoxygenase, and catalase activity thought to be important in protection against host immune responses to infection. In this study, we generated a monoclonal antibody (48Eg) against haemoglobin of the nematode Anisakis pegreffii, and aimed to characterize cross-reactivity of 4E8g against haemoglobins of different nematodes and its potential to mediate protective immunity against a murine hookworm infection. METHODOLOGY/PRINCIPAL FINDINGS: Immunoprecipitation was used to isolate the 4E8g-binding antigen in Anisakis and Ascaris extracts, which were identified as haemoglobins by peptide mass fingerprinting and MS/MS. Immunological cross-reactivity was also demonstrated with haemoglobin of the rodent hookworm N. brasiliensis. Immunogenicity of nematode haemoglobin in mice and humans was tested by immunoblotting. Anisakis haemoglobin was recognized by IgG and IgE antibodies of Anisakis-infected mice, while Ascaris haemoglobin was recognized by IgG but not IgE antibodies in mouse and human sera. Sequencing of Anisakis haemoglobin revealed high similarity to haemoglobin of a related marine nematode, Psuedoterranova decipiens, which lacks the four -HKEE repeats of Ascaris haemoglobin important in octamer assembly. The localization of haemoglobin in the different parasites was examined by immunohistochemistry and associated with the excretory-secretary ducts in Anisakis, Ascaris and N. brasiliensis. Anisakis haemoglobin was strongly expressed in the L3 stage, unlike Ascaris haemoglobin, which is reportedly mainly expressed in adult worms. Passive immunization of mice with 4E8g prior to infection with N. brasiliensis enhanced protective Th2 immunity and led to a significant decrease in worm burdens. CONCLUSION: The monoclonal antibody 4E8g targets haemoglobin in broadly equivalent anatomical locations in parasitic nematodes and enhances host immunity to a hookworm infection.
Assuntos
Anisakis/imunologia , Anticorpos Anti-Helmínticos/imunologia , Anticorpos Monoclonais/imunologia , Reações Cruzadas , Hemoglobinas/imunologia , Nippostrongylus/imunologia , Infecções por Strongylida/imunologia , Animais , Anisakis/genética , Anticorpos Anti-Helmínticos/administração & dosagem , Anticorpos Anti-Helmínticos/isolamento & purificação , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais/isolamento & purificação , Antígenos de Helmintos/química , Antígenos de Helmintos/genética , Antígenos de Helmintos/imunologia , Ascaris/imunologia , Modelos Animais de Doenças , Hemoglobinas/química , Hemoglobinas/genética , Humanos , Imunização Passiva , Immunoblotting , Imunoglobulina E/sangue , Imunoglobulina G/sangue , Imuno-Histoquímica , Imunoprecipitação , Camundongos , Camundongos Endogâmicos BALB C , Nematoides , Análise de Sequência de DNA , Espectrometria de Massas em Tandem , Resultado do TratamentoRESUMO
Hookworms represent a major infectious burden globally, especially in developing countries. The murine hookworm Nippostrongylus brasiliensis is normally cleared in a manner dependent on IL-13, IL4-R and STAT6 signalling. Here we have used STAT6-deficient animals to model a non-resistant population and describe 2 novel STAT6-independent processes for the clearance of N. brasiliensis. During primary infection STAT6-/- animals are able to clear gut-dwelling N. brasiliensis by a mechanism involving the trapping and degradation of worms in the gut mucosa. Here, a previously undescribed STAT6-independent up-regulation of Relm-ß was observed which correlated with the mucosal trapping and degradation of worms. Previous studies have indicated that during secondary infection STAT6 deficient animals fail to expel adult worms and remain susceptible to re-infection and long-term colonization of the gut. We report here that an initial partially protective response occurs early upon re-infection in the absence of STAT6, and that a late-phase protective secondary response arises in the gut of STAT6-deficient mice leading to the clearance of the majority of N. brasiliensis, through their trapping and death in the mucosal layer of the lower region of the small intestine. These findings show that there are a number of redundant effector pathways which act to reduce worm burden in the gut which can be activated by mechanisms that do not work through the dominant STAT6 signalling pathway and may be useful as targets for future vaccination strategies against resistant hookworm strains.
Assuntos
Mucosa Intestinal/imunologia , Mucosa Intestinal/parasitologia , Nippostrongylus/imunologia , Fator de Transcrição STAT6/deficiência , Fator de Transcrição STAT6/imunologia , Infecções por Strongylida/imunologia , Infecções por Strongylida/parasitologia , Animais , Citometria de Fluxo , Trato Gastrointestinal/imunologia , Trato Gastrointestinal/parasitologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Nippostrongylus/genética , RNA de Helmintos/química , RNA de Helmintos/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fator de Transcrição STAT6/genética , Transdução de Sinais , Organismos Livres de Patógenos EspecíficosRESUMO
The intestinal parasitic nematode Nippostrongylus brasiliensis is expelled rapidly from the rat in reinfection challenge compared with that of the primary infection owing to the host defense mechanisms raised against the pre-intestinal- and intestinal-stage larvae. We examined the relationship between the mucin alterations in airway and jejunal mucosae and the worm expulsion after third-stage larva reinfection. When rats had been inoculated with fourth-stage larvae and immunized with only the intestinal-stage worms for more than 8 days, the challenge larvae were expelled during the intestinal stage along with a rapid increase of the specific sialomucin in jejunal mucosa, without any effect on the bronchial mucus. When rats had been infected with third-stage larvae and immunized with only the pre-intestinal stage larvae by killing with antihelminthic, the challenge larvae were rejected during the pre-intestinal stage along with marked goblet cell hyperplasia and Muc5AC mucin hyperproduction on the bronchial mucosa, but not as a result of jejunal mucin alteration. Taking these finding together, immunization with pre-intestinal- and intestinal-stage worms independently increases the airway and intestinal goblet cell mucins, respectively, and in both cases, the mucin alterations may contribute to rapid worm expulsion upon reinfection.
Assuntos
Células Caliciformes/metabolismo , Jejuno/metabolismo , Pulmão/metabolismo , Mucinas/metabolismo , Nippostrongylus/imunologia , Infecções por Strongylida/imunologia , Administração Oral , Animais , Antiparasitários/administração & dosagem , Histocitoquímica , Ivermectina/administração & dosagem , Larva/imunologia , Masculino , Ratos , Ratos Wistar , Recidiva , Infecções por Strongylida/tratamento farmacológicoRESUMO
Granulocyte macrophage-colony stimulating factor (GM-CSF) is a cytokine with the capacity to promote inflammation in a wide variety of infectious and inflammatory diseases. These conditions include allergic airway inflammation, which is driven by T-helper 2 (Th2) cells. Because of the importance of Th2 cells in parasite infections, we have investigated the role of GM-CSF in mice infected with the nematode Nippostrongylus brasiliensis. The effect of primary and secondary infection was investigated in mice lacking functional genes for GM-CSF (CSF2 genes) (ΔGM-CSF mice), and in mice lacking the cytokine receptor common ß chain (Δß mice), the latter being unable to signal in response to GM-CSF and interleukin (IL)-5. ΔGM-CSF mice showed no significant defect in parasite immunity, measured by larval numbers in the lungs, worm numbers in the intestine or egg numbers in the faeces, in either primary or secondary infection. By contrast, the Δß mice showed increased parasite burden, with higher numbers of lung larvae after secondary infection and higher numbers of intestinal worms and faecal eggs after both primary and secondary infection. Unexpectedly, there were increased numbers of circulating eosinophils in the ΔGM-CSF mice, associated with significantly reduced larval numbers in the lungs. These results indicate that GM-CSF is redundant in protection against N. brasiliensis infection, and that the increased susceptibility of Δß mice to infection is likely to be attributed to the lack of IL-5 signalling in these mice. The results suggest that clinical use of agents that neutralise GM-CSF may not be associated with increased risk of parasite infection.
Assuntos
Subunidade beta Comum dos Receptores de Citocinas/metabolismo , Eosinófilos/imunologia , Fator Estimulador de Colônias de Granulócitos e Macrófagos/metabolismo , Nippostrongylus/imunologia , Infecções por Strongylida/imunologia , Infecções por Strongylida/prevenção & controle , Animais , Subunidade beta Comum dos Receptores de Citocinas/genética , Subunidade beta Comum dos Receptores de Citocinas/imunologia , Fator Estimulador de Colônias de Granulócitos e Macrófagos/genética , Fator Estimulador de Colônias de Granulócitos e Macrófagos/imunologia , Imunoglobulina E/sangue , Intestinos/imunologia , Intestinos/parasitologia , Larva , Pulmão/imunologia , Pulmão/parasitologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Carga Parasitária , Células Th2/imunologiaRESUMO
The intestinal epithelium is rich in γδ T cells and the gut is a site of residence for a wide variety of pathogens, including nematodes. Although CD4+ T-cell receptor (TCR) -αß+ T helper type 2 T cells are essential for the expulsion of intestinal nematodes, little information is available on the function of γδ T cells in this type of infection. Here, we demonstrate two major functions of γδ T cells as a potently protective T-cell population against Nippostrongylus brasiliensis infection using γδ T-cell-deficient (TCR-δ(-/-) ) mice. First, γδ T cells are required to initiate rapid expulsion of adult worms from the intestine and to limit egg production. Second, γδ T cells prevent the pathological intestinal damage associated with nematode infection, evident by increased clinical disease and more severe microscopic lesions in infected TCR-δ(-/-) mice. γδ T-cell deficiency led to delayed goblet cell hyperplasia in association with reduced expression of phosphorylated STAT6, MUC2, Trefoil factor-3 (TFF3) and T helper type 2 cytokines including interleukin-13 (IL-13). TCR-δ(-/-) mice also produced more interferon-γ than wild-type mice. Within the intraepithelial lymphocyte compartment, γδ T cells produced IL-13. Adoptive transfer of γδ T cells or administration of recombinant IL-13 to TCR-δ(-/-) mice successfully reduced the egg production by N. brasiliensis. Collectively, these data provide strong evidence that γδ T cells play an important role in controlling infection with intestinal nematodes and limiting infection-induced pathology.
Assuntos
Células Caliciformes/imunologia , Imunidade nas Mucosas , Nippostrongylus/imunologia , Receptores de Antígenos de Linfócitos T gama-delta/imunologia , Infecções por Strongylida/imunologia , Subpopulações de Linfócitos T/imunologia , Animais , Proliferação de Células , Células Caliciformes/patologia , Interleucina-13/imunologia , Intestino Delgado/imunologia , Intestino Delgado/patologia , Camundongos , Mucina-2/imunologia , Mucinas/imunologia , Fator de Transcrição STAT6/imunologia , Fator Trefoil-3RESUMO
The parasitic gastrointestinal nematode Nippostrongylus brasiliensis induces massive expansion of T helper type 2 (Th2) cells in the lung and small intestine. Th2 cells are a major source of interleukin-4 and interleukin-13, two cytokines that appear essential for rapid worm expulsion. It is unclear whether all Th2 cells induced during infection are pathogen-specific because Th2 cells might also be induced by parasite-derived superantigens or cytokine-mediated bystander activation. Bystander Th2 polarization could explain the largely unspecific B-cell response during primary infection. Furthermore, it is not known whether protective immunity depends on a polyclonal repertoire of T-cell receptor (TCR) specificities. To address these unresolved issues, we performed adoptive transfer experiments and analysed the TCR-Vß repertoire before and after infection of mice with the helminth N. brasiliensis. The results demonstrate that all Th2 cells were generated by antigen-specific rather than superantigen-driven or cytokine-driven activation. Furthermore, we show that worm expulsion was impaired in mice with a limited repertoire of TCR specificities, indicating that a polyclonal T-cell response is required for protective immunity.
Assuntos
Nippostrongylus/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Infecções por Strongylida/imunologia , Transferência Adotiva , Animais , Imunoglobulina E/sangue , Imunoglobulina E/imunologia , Interleucina-13/imunologia , Interleucina-4/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Transgênicos , Receptores de Antígenos de Linfócitos T/genética , Células Th2/imunologiaRESUMO
Nippostrongylus brasiliensis infections generate pulmonary pathologies that can be associated with strong T(H)2 polarization of the host's immune response. We present data demonstrating N. brasiliensis-driven airway mucus production to be dependent on smooth muscle cell interleukin 4 receptor-α (IL-4Rα) responsiveness. At days 7 and 10 post infection (PI), significant airway mucus production was found in IL-4Rα(-/lox) control mice, whereas global knockout (IL-4Rα(-/-)) and smooth muscle-specific IL-4Rα-deficient mice (SM-MHC(Cre) IL-4Rα(-/lox)) showed reduced airway mucus responses. Furthermore, interleukin (IL)-13 and IL-5 cytokine production in SM-MHC(Cre) IL-4Rα(-/lox) mice was impaired along with a transient reduction in T-cell numbers in the lung. In vitro treatment of smooth muscle cells with secreted N. brasiliensis excretory-secretory antigen (NES) induced IL-6 production. Decreased protein kinase C (PKC)-dependent smooth muscle cell proliferation associated with cell cycle arrest was found in cells stimulated with NES. Together, these data demonstrate that both IL-4Rα and NES-driven responses by smooth muscle cells make important contributions in initiating T(H)2 responses against N. brasiliensis infections.
Assuntos
Subunidade alfa de Receptor de Interleucina-4/imunologia , Pneumopatias Parasitárias/imunologia , Miócitos de Músculo Liso/imunologia , Miócitos de Músculo Liso/metabolismo , Nippostrongylus/imunologia , Infecções por Strongylida/imunologia , Células Th2/imunologia , Animais , Ciclo Celular/genética , Citometria de Fluxo , Interleucina-13/biossíntese , Interleucina-13/imunologia , Subunidade alfa de Receptor de Interleucina-4/genética , Subunidade alfa de Receptor de Interleucina-4/metabolismo , Interleucina-5/biossíntese , Interleucina-5/imunologia , Interleucina-6/biossíntese , Interleucina-6/imunologia , Pneumopatias Parasitárias/patologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Muco/metabolismo , Nippostrongylus/patogenicidade , Proteína Quinase C/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais , Infecções por Strongylida/patologiaRESUMO
The caliber and magnitude of T cell responses are regulated by costimulatory molecules following the engagement of TCRs and MHC molecules. B7-DC has the highest homology with B7-H1 in the B7 family, and both of them bind an immunoregulatory molecule, programmed death 1. Previous studies have demonstrated that B7-DC stimulates T cell proliferation and CTL generation, which sharply contrasts the inhibitory role of B7-H1. Th2 cytokines prompt B7-DC expression, which in turn enhances Th1 responses. In this study, we used an intestinal nematode, Nippostrongylus brasiliensis, to induce strong Th2 responses and to evaluate B7-DC function under Th2-polarizing conditions in vivo. By either blocking B7-DC expression during N. brasiliensis infection or by examining N. brasiliensis-infected B7-DC knockout mice, we observed enhanced eosinophilia, the overproduction of serum IgE, and increased Th2 cytokine production along with decreased Th1 cytokine production (particularly IFN-gamma production), indicating that B7-DC inhibits Th2 responses. Our results further demonstrate that the inhibition of Th2 responses by B7-DC occurs independently of programmed death 1 but conceivably acts through an as yet unknown alternative receptor that enhances Th1 responses. Although the deficiency of B7-DC expression that enhanced the production of IL-13 paradoxically resulted in better protection against N. brasiliensis infection, our results show that B7-DC plays an important role in bolstering a robust Th1 response that is required for effective antiviral and anticancer immunity, even under a strong Th2-polarizing environment induced by N. brasiliensis infection.
Assuntos
Antígeno B7-1/fisiologia , Nippostrongylus/imunologia , Infecções por Strongylida/imunologia , Células Th2/imunologia , Animais , Antígeno B7-1/genética , Células Cultivadas , Eosinofilia/imunologia , Eosinofilia/parasitologia , Retroalimentação Fisiológica , Imunoglobulina E/biossíntese , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Camundongos Transgênicos , Proteína 2 Ligante de Morte Celular Programada 1 , Células Th2/metabolismo , Células Th2/parasitologiaRESUMO
BACKGROUND: Larvae of several common species of parasitic nematodes obligately migrate through, and often damage, host lungs. The larvae induce strong pulmonary Type 2 immune responses, including T-helper (Th)2 cells as well as alternatively activated macrophages (AAMphi) and associated chitinase and Fizz/resistin family members (ChaFFs), which are thought to promote tissue repair processes. Given the prevalence of systemic or lung-resident Type 1-inducing pathogens in geographical areas in which nematodes are endemic, we wished to investigate the impact of concurrent Type 1 responses on the development of these Type 2 responses to nematode larval migration. We therefore infected BALB/c mice with the nematode Nippostrongylus brasiliensis, in the presence or absence of Plasmodium chabaudi chabaudi malaria parasites. Co-infected animals received both infections on the same day, and disease was assessed daily before immunological measurements were taken at 3, 5, 7 or 20 days post-infection. RESULTS: We observed that the nematodes themselves caused transient loss of body mass and red blood cell density, but co-infection then slightly ameliorated the severity of malarial anaemia. We also tracked the development of immune responses in the lung and thoracic lymph node. By the time of onset of the adaptive immune response around 7 days post-infection, malaria co-infection had reduced pulmonary expression of ChaFFs. Assessment of the T cell response demonstrated that the Th2 response to the nematode was also significantly impaired by malaria co-infection. CONCLUSION: P. c. chabaudi co-infection altered both local and lymph node Type 2 immune activation due to migration of N. brasiliensis larvae. Given recent work from other laboratories showing that N. brasiliensis-induced ChaFFs correlate to the extent of long-term lung damage, our results raise the possibility that co-infection with malaria might alter pulmonary repair processes following nematode migration. Further experimentation in the co-infection model developed here will reveal the longer-term consequences of the presence of both malaria and helminths in the lung.
Assuntos
Ativação Linfocitária/imunologia , Malária/imunologia , Nippostrongylus/imunologia , Plasmodium chabaudi/imunologia , Infecções por Strongylida/imunologia , Células Th1/metabolismo , Células Th2/metabolismo , Anemia , Animais , Feminino , Larva , Pulmão/imunologia , Pulmão/parasitologia , Pulmão/patologia , Malária/complicações , Malária/patologia , Malária/fisiopatologia , Camundongos , Camundongos Endogâmicos BALB C , Nippostrongylus/patogenicidade , Plasmodium chabaudi/patogenicidade , Infecções por Strongylida/complicações , Infecções por Strongylida/patologia , Infecções por Strongylida/fisiopatologia , Células Th1/imunologia , Células Th1/parasitologia , Células Th1/patologia , Células Th2/imunologia , Células Th2/parasitologia , Células Th2/patologia , CicatrizaçãoRESUMO
Infections with the parasitic helminth, Nippostrongylus brasiliensis, cause changes in rat small intestinal goblet cell mucin, particularly in the peripheral sugar residues of oligosaccharide. These changes may correlate with expulsion. In this study, we examined changes in mucin oligosaccharides caused by primary infection and reinfection with N. brasiliensis, using two monoclonal antibodies, HCM31 and PGM34, that react with sialomucin and sulfomucin, respectively. Enzyme-linked immunosorbent assay of jejunal mucins showed that the relative reactivity of mucins with HCM31, but not PGM34, increased up to 16 days after primary infection and 6 days after reinfection, the times when the worms were expelled from the rats. Immunohistochemical studies confirmed that goblet cells stained with HCM31 greatly increased at the time of worm expulsion. These results indicate that the marked increase observed in HCM31-reactive sialomucins may be related to expulsion of the worms.
Assuntos
Enteropatias Parasitárias/metabolismo , Jejuno/metabolismo , Nippostrongylus/fisiologia , Sialomucinas/metabolismo , Infecções por Strongylida/metabolismo , Animais , Anticorpos Monoclonais/imunologia , Ensaio de Imunoadsorção Enzimática , Fezes/parasitologia , Células Caliciformes/metabolismo , Imunidade nas Mucosas , Imuno-Histoquímica , Enteropatias Parasitárias/imunologia , Mucosa Intestinal/metabolismo , Mucosa Intestinal/parasitologia , Jejuno/parasitologia , Cinética , Lectinas , Masculino , Nippostrongylus/imunologia , Contagem de Ovos de Parasitas , Ratos , Ratos Wistar , Sialomucinas/imunologia , Infecções por Strongylida/imunologiaRESUMO
IL-13 has a prominent role in host defense against the gastrointestinal nematode Nippostrongylus brasiliensis; however, the role of IL-13Ralpha2 in the immune and functional response to enteric infection is not known. In the current study, we investigated changes in smooth muscle and epithelial cell function as well as alterations in gene expression of IL-13 and IL-4 and their receptors using laser-capture microdissection of specific cell types in the small intestine of N. brasiliensis-infected mice. An infection-induced up-regulation of IL-13Ralpha2 gene expression was confined to smooth muscle and was dependent on STAT6 and IL-13, but not on IL-4. In contrast, expression of IL-13Ralpha1 was reduced, indicating that changes in IL-13alpha2 expression serve to limit the biological effects of IL-13. The increased availability of IL-13 in IL-13Ralpha2(-/-) mice resulted in marked changes in constitutive epithelial and smooth muscle function. In addition, maximal changes in smooth muscle hypercontractility and epithelial cell resistance peaked earlier after infection in IL-13Ralpha2(-/-) compared with wild-type mice. This did not coincide with an earlier Th2 immune response as expression of IL-4 and IL-13 was attenuated in IL-13Ralpha2(-/-) mice and worm expulsion was similar to that of wild-type mice. These data show that IL-13Ralpha2 plays an important role in nematode infection by limiting the availability of IL-13 during infection, thereby regulating both the immune and biological effects of IL-13.
Assuntos
Subunidade alfa2 de Receptor de Interleucina-13/imunologia , Nippostrongylus/imunologia , Infecções por Strongylida/imunologia , Animais , Regulação da Expressão Gênica/imunologia , Imunidade , Interleucina-13 , Interleucina-4 , Camundongos , Camundongos Endogâmicos BALB C , Músculo Liso/metabolismo , Fator de Transcrição STAT6RESUMO
Periparturient relaxation of immunity (PPRI) to secondary infection with nematodes is believed to have a nutritional basis due to differential partitioning of scarce nutrient resources, particularly protein, to reproductive rather than immune functions. At times of protein scarcity, an increase in protein supply has been reported to assuage this phenomenon. The Nippostrongylus brasiliensis reinfected lactating rat model is now being utilized to investigate the immune reactions underlying the modifying role of dietary protein on PPRI. Herein, we demonstrate that lactating rats reinfected with N. brasiliensis under high protein (HP) dietary conditions exhibit decreased worm burdens and reduced colon egg counts compared to their low protein (LP) counterparts. These reductions correlated with increased mastocytosis and greater goblet cell hyperplasia. Additionally, the local antibody profile revealed that HP reinfected lactating rats developed a stronger antigen specific IgG2b response earlier in infection in comparison with their LP counterparts. Our study provides evidence that increased dietary protein content reduces the PPRI to N. brasiliensis re-infection in the lactating rat through improved mucosal immune responses.