RESUMO
Malaria is associated with complicated immunopathogenesis. In this study, we provide evidence for an unexpected role of TLR3 in promoting the establishment of Plasmodium yoelii infection through delayed clearance of parasitemia in wild type C57BL/6jRj (B6) compared with TLR3 knockout mice. In this study, we confirmed an increased expression of Tlr3, Trif, Tbk1, and Irf7/Irf3 in the liver 42 h postinfection and the initiation of an early burst of proinflammatory response such as Ifng, NF-kB, and Tnfa in B6 mice that may promote parasite fitness. Interestingly, in the absence of TLR3, we showed the involvement of high IFN-γ and lower type I IFN response in the early clearance of parasitemia. In parallel, we observed an increase in splenic NK and NKT cells expressing TLR3 in infected B6 mice, suggesting a role for TLR sensing in the innate immune response. Finally, we find evidence that the increase in the frequency of CD19+TLR3+ B cells along with reduced levels of total IgG in B6 mice possibly suggests the initiation of TLR3-dependent pathway early during P. yoelii infection. Our results thus reveal a new mechanism in which a parasite-activated TLR3 pathway promotes blood stage infection along with quantitative and qualitative differences in Ab responses.
Assuntos
Malária/imunologia , Mamíferos/imunologia , Mamíferos/parasitologia , Plasmodium yoelii/imunologia , Receptor 3 Toll-Like/imunologia , Animais , Linfócitos B/imunologia , Imunidade Inata/imunologia , Imunoglobulina G/imunologia , Inflamação/imunologia , Inflamação/parasitologia , Interferon Tipo I/imunologia , Interferon gama/imunologia , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/parasitologia , Malária/parasitologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , NF-kappa B/imunologia , Células T Matadoras Naturais/imunologia , Células T Matadoras Naturais/parasitologia , Parasitemia/imunologia , Transdução de Sinais/imunologia , Fator de Necrose Tumoral alfa/imunologiaRESUMO
BACKGROUND: Malaria in pregnancy causes maternal, fetal and neonatal morbidity and mortality, and maternal innate immune responses are implicated in pathogenesis of these complications. The effects of malaria exposure and obstetric and demographic factors on the early maternal immune response are poorly understood. METHODS: Peripheral blood mononuclear cell responses to Plasmodium falciparum-infected erythrocytes and phytohemagglutinin were compared between pregnant women from Papua New Guinea (malaria-exposed) with and without current malaria infection and from Australia (unexposed). Elicited levels of inflammatory cytokines at 48 h and 24 h (interferon γ, IFN-γ only) and the cellular sources of IFN-γ were analysed. RESULTS: Among Papua New Guinean women, microscopic malaria at enrolment did not alter peripheral blood mononuclear cell responses. Compared to samples from Australia, cells from Papua New Guinean women secreted more inflammatory cytokines tumor necrosis factor-α, interleukin 1ß, interleukin 6 and IFN-γ; p<0.001 for all assays, and more natural killer cells produced IFN-γ in response to infected erythrocytes and phytohemagglutinin. In both populations, cytokine responses were not affected by gravidity, except that in the Papua New Guinean cohort multigravid women had higher IFN-γ secretion at 24 h (p = 0.029) and an increased proportion of IFN-γ+ Vδ2 γδ T cells (p = 0.003). Cytokine levels elicited by a pregnancy malaria-specific CSA binding parasite line, CS2, were broadly similar to those elicited by CD36-binding line P6A1. CONCLUSIONS: Geographic location and, to some extent, gravidity influence maternal innate immunity to malaria.
Assuntos
Imunidade Inata/genética , Malária Falciparum/imunologia , Plasmodium falciparum/imunologia , Complicações Parasitárias na Gravidez/imunologia , Adolescente , Adulto , Austrália/epidemiologia , Antígenos CD36/genética , Eritrócitos/imunologia , Eritrócitos/parasitologia , Eritrócitos/patologia , Feminino , Número de Gestações/imunologia , Humanos , Interferon gama/genética , Interferon gama/imunologia , Interleucina-6/genética , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/parasitologia , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/parasitologia , Leucócitos Mononucleares/patologia , Malária Falciparum/epidemiologia , Malária Falciparum/parasitologia , Pessoa de Meia-Idade , Papua Nova Guiné/epidemiologia , Plasmodium falciparum/patogenicidade , Gravidez , Complicações Parasitárias na Gravidez/parasitologia , Complicações Parasitárias na Gravidez/patologia , Linfócitos T/imunologia , Linfócitos T/parasitologia , Adulto JovemRESUMO
Both CD8+ T cells and NK cells contribute to the immune response against the protozoan Leishmania parasite. Both are able to generate IFN-γ and both display cytotoxic features. These features may enable them to not only contribute to parasite clearance but also to cause immune-mediated pathology. This pathology is evident, for example, in the Leismania-induced skin lesions found in patients with cutaneous leismaniasis (CL). Here we highlight new data demonstrating that CD8+ T cells and NK cells in CL display a highly cytotoxic senescent phenotype, and that the senescent T cells play a major role in mediating skin pathology. This is the first demonstration that senescent CD8 T cells contribute to immunopathology in vivo.
Assuntos
Citotoxicidade Imunológica , Leishmania braziliensis/patogenicidade , Leishmaniose Cutânea/patologia , Pele/patologia , Linfócitos T Citotóxicos/patologia , Antígenos CD57/genética , Antígenos CD57/imunologia , Senescência Celular/imunologia , Expressão Gênica , Interações Hospedeiro-Parasita/genética , Interações Hospedeiro-Parasita/imunologia , Humanos , Interferon gama/genética , Interferon gama/imunologia , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/parasitologia , Células Matadoras Naturais/patologia , Leishmania braziliensis/imunologia , Leishmaniose Cutânea/imunologia , Leishmaniose Cutânea/parasitologia , Oligossacarídeos/genética , Oligossacarídeos/imunologia , Antígeno Sialil Lewis X/análogos & derivados , Antígeno Sialil Lewis X/genética , Antígeno Sialil Lewis X/imunologia , Pele/imunologia , Pele/parasitologia , Linfócitos T Citotóxicos/imunologia , Linfócitos T Citotóxicos/parasitologiaRESUMO
Cytotoxic activity mediated by CD8+ T cells is the main signature of the immunopathogenesis of cutaneous leishmaniasis (CL). Here, we performed a broad evaluation of natural killer (NK) cell phenotypic and functional features during cutaneous leishmaniasis. We demonstrate for the first time that CL patients present the accumulation of circulating NK cells with multiple features of replicative senescence including low proliferative capacity and shorter telomeres, elevated expression of CD57, KLRG1 but diminished CD27 stimulatory receptor expression. Moreover, they exhibited higher cytotoxic and inflammatory potential than age-matched controls. The accumulation of circulating senescent NK cells (CD56dim CD57bright ) correlated positively with skin lesion size in the same patients, suggesting that they, like circulating senescent CD8+ T cells, may contribute to the immunopathology of CL. However, this senescent population had lower cutaneous lymphocyte antigen expression and so had diminished skin-homing potential compared with total or senescent CD8+ T cells. This was confirmed in CL skin lesions where we found a predominance of CD8+ T cells (both senescent and non-senescent) that correlated with the severity of the disease. Although there was also a correlation between the proportions of senescent NK cells (CD56+ CD57+ ) in the skin and lesion size, this was less evident. Collectively our results demonstrate first-hand that senescent cytotoxic cells may mediate skin pathology during human cutaneous leishmaniasis. However, as senescent cytotoxic CD8+ T cells predominate in the skin lesions, they may have a greater role than NK cells in mediating the non-specific skin damage in CL.
Assuntos
Citotoxicidade Imunológica , Células Matadoras Naturais/patologia , Leishmania braziliensis/patogenicidade , Leishmaniose Cutânea/patologia , Pele/patologia , Linfócitos T Citotóxicos/patologia , Antígeno CD56/genética , Antígeno CD56/imunologia , Antígenos CD57/genética , Antígenos CD57/imunologia , Estudos de Casos e Controles , Senescência Celular/imunologia , Feminino , Regulação da Expressão Gênica , Interações Hospedeiro-Parasita/genética , Interações Hospedeiro-Parasita/imunologia , Humanos , Interferon gama/genética , Interferon gama/imunologia , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/parasitologia , Lectinas Tipo C/genética , Lectinas Tipo C/imunologia , Leishmania braziliensis/imunologia , Leishmaniose Cutânea/imunologia , Leishmaniose Cutânea/parasitologia , Masculino , Oligossacarídeos/genética , Oligossacarídeos/imunologia , Receptores Imunológicos/genética , Receptores Imunológicos/imunologia , Índice de Gravidade de Doença , Antígeno Sialil Lewis X/análogos & derivados , Antígeno Sialil Lewis X/genética , Antígeno Sialil Lewis X/imunologia , Transdução de Sinais , Pele/imunologia , Pele/parasitologia , Linfócitos T Citotóxicos/imunologia , Linfócitos T Citotóxicos/parasitologiaRESUMO
Natural killer (NK) cells are important innate effector cells that are well described in their ability to kill virally-infected cells and tumors. However, there is increasing appreciation for the role of NK cells in the control of other pathogens, including intracellular parasites such as Plasmodium, the cause of malaria. NK cells may be beneficial during the early phase of Plasmodium infection-prior to the activation and expansion of antigen-specific T cells-through cooperation with myeloid cells to produce inflammatory cytokines like IFNγ. Recent work has defined how Plasmodium can activate NK cells to respond with natural cytotoxicity, and inhibit the growth of parasites via antibody-dependent cellular cytotoxicity mechanisms (ADCC). A specialized subset of adaptive NK cells that are negative for the Fc receptor γ chain have enhanced ADCC function and correlate with protection from malaria. Additionally, production of the regulatory cytokine IL-10 by NK cells prevents overt pathology and death during experimental cerebral malaria. Now that conditional NK cell mouse models have been developed, previous studies need to be reevaluated in the context of what is now known about other immune populations with similarity to NK cells (i.e., NKT cells and type I innate lymphoid cells). This brief review summarizes recent findings which support the potentially beneficial roles of NK cells during Plasmodium infection in mice and humans. Also highlighted are how the actions of NK cells can be explored using new experimental strategies, and the potential to harness NK cell function in vaccination regimens.
Assuntos
Imunidade Inata , Células Matadoras Naturais/imunologia , Plasmodium/fisiologia , Animais , Humanos , Células Matadoras Naturais/parasitologia , CamundongosRESUMO
Natural killer (NK) cells provide the first line of defense against malaria parasite infection. However, the molecular mechanisms through which NK cells are activated by parasites are largely unknown, so is the molecular basis underlying the variation in NK cell responses to malaria infection in the human population. Here, we compared transcriptional profiles of responding and non-responding NK cells following exposure to Plasmodium-infected red blood cells (iRBCs) and identified MDA5, a RIG-I-like receptor involved in sensing cytosolic RNAs, to be differentially expressed. Knockout of MDA5 in responding human NK cells by CRISPR/cas9 abolished NK cell activation, IFN-γ secretion, lysis of iRBCs. Similarly, inhibition of TBK1/IKKε, an effector molecule downstream of MDA5, also inhibited activation of responding NK cells. Conversely, activation of MDA5 by liposome-packaged poly I:C restored non-responding NK cells to lyse iRBCs. We further show that microvesicles containing large parasite RNAs from iRBCs activated NK cells by fusing with NK cells. These findings suggest that NK cells are activated through the MDA5 pathway by parasite RNAs that are delivered to the cytoplasm of NK cells by microvesicles from iRBCs. The difference in MDA5 expression between responding and non-responding NK cells following exposure to iRBCs likely contributes to the variation in NK cell responses to malaria infection in the human population.
Assuntos
Micropartículas Derivadas de Células/imunologia , Eritrócitos/imunologia , Helicase IFIH1 Induzida por Interferon/metabolismo , Células Matadoras Naturais/imunologia , Malária Falciparum/imunologia , Plasmodium falciparum/imunologia , Sistemas CRISPR-Cas , Células Cultivadas , Citoplasma/metabolismo , Eritrócitos/metabolismo , Eritrócitos/parasitologia , Humanos , Helicase IFIH1 Induzida por Interferon/antagonistas & inibidores , Helicase IFIH1 Induzida por Interferon/genética , Células Matadoras Naturais/metabolismo , Células Matadoras Naturais/parasitologia , Ativação Linfocitária , Malária Falciparum/metabolismo , Malária Falciparum/parasitologia , Plasmodium falciparum/isolamento & purificaçãoRESUMO
This study aimed to induce protective immunity against infection with Sarcocystis muris in experimental mice using ß-irradiated sporocysts. Mice were vaccinated with 50 sporocysts of S. muris which were exposed to 1.84⯵Sv ß-irradiation for 2, 4 and 8â¯h. After challenge infection, different samples were taken for evaluation. Serum and intestinal wash were assayed for IFN-γ and IgA, respectively. Mesenteric lymph nodes (MLNs) and spleen were investigated for CD4+ and CD8+ T cells using immunohistochemistry. For liver, the morphological changes in parasitic stages and the count of infiltrated CD8+ T, NK1.1+ and FasL+ cells were also investigated. Real time (RT) - PCR was used for detection of liver MHC I, CD1d, IFN-γ, perforin and FasL as well as the parasite 18S ribosomal(r) RNA in liver and muscle tissues. Alterations of liver parasitic stages as well as a decrease in the infection with the parasite in both of liver and muscle tissues were dependent on radiation exposure time. An investigation for the mechanism of immunoprotection showed an increase in liver NK1.1+ & FasL+ cells, serum IFN-γ and intestinal IgA, while CD4+ and CD8+ T showed a remarkable increase in MLNs and spleen. FasL expression increased in the liver dependently on radiation exposure time, while perforin, MHC I and CD1d were not. ß-irradiated sporocysts with 1.84⯵Sv for 8â¯hâ¯s could induce the highest protection against infection with Sarcocystis. This could be largely relied on the increased infiltration of NK cells and associated higher expression of FasL in the liver.
Assuntos
Sarcocystis/imunologia , Sarcocystis/efeitos da radiação , Sarcocistose/prevenção & controle , Vacinação/métodos , Animais , Partículas beta , Linfócitos T CD4-Positivos/citologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/imunologia , Gatos , Modelos Animais de Doenças , Proteína Ligante Fas/metabolismo , Imunoglobulina A/análise , Interferon gama/análise , Interferon gama/sangue , Interferon gama/genética , Intestinos/imunologia , Células Matadoras Naturais/citologia , Células Matadoras Naturais/parasitologia , Fígado/citologia , Fígado/imunologia , Fígado/parasitologia , Linfonodos/citologia , Linfonodos/imunologia , Mesentério , Camundongos , Músculo Esquelético/parasitologia , Oocistos/genética , Oocistos/imunologia , Oocistos/efeitos da radiação , RNA Mensageiro/metabolismo , Sarcocystis/genética , Sarcocistose/imunologia , Baço/citologia , Baço/imunologiaRESUMO
Cutaneous leishmaniasis (CL) is a chronic disease caused by species of the protozoan Leishmania and characterised by the presence of ulcerated skin lesions. Both parasite and host factors affect the clinical presentation of the disease. The development of skin ulcers in CL is associated with an inflammatory response mediated by cells that control parasite growth but also contribute to pathogenesis. CD8+ T cells contribute to deleterious inflammatory responses in patients with CL through cytotoxic mechanisms. In addition, natural killer cells also limit Leishmania infections by production of interferon-γ and cytotoxicity. In this review, we focus on studies of cytotoxicity in CL and its contribution to the pathogenesis of this disease.
Assuntos
Linfócitos T CD8-Positivos/parasitologia , Citotoxicidade Imunológica/imunologia , Células Matadoras Naturais/parasitologia , Leishmaniose Cutânea/imunologia , Linfócitos T Citotóxicos/parasitologia , Animais , Linfócitos T CD8-Positivos/imunologia , Modelos Animais de Doenças , Humanos , Células Matadoras Naturais/imunologia , Leishmaniose Cutânea/patologia , Linfócitos T Citotóxicos/imunologiaRESUMO
Cutaneous leishmaniasis (CL) is a chronic disease caused by species of the protozoan Leishmania and characterised by the presence of ulcerated skin lesions. Both parasite and host factors affect the clinical presentation of the disease. The development of skin ulcers in CL is associated with an inflammatory response mediated by cells that control parasite growth but also contribute to pathogenesis. CD8+ T cells contribute to deleterious inflammatory responses in patients with CL through cytotoxic mechanisms. In addition, natural killer cells also limit Leishmania infections by production of interferon-γ and cytotoxicity. In this review, we focus on studies of cytotoxicity in CL and its contribution to the pathogenesis of this disease.
Assuntos
Humanos , Animais , Células Matadoras Naturais/efeitos dos fármacos , Células Matadoras Naturais/parasitologia , Linfócitos T Citotóxicos/imunologia , Leishmaniose Cutânea/imunologia , Leishmaniose Cutânea/patologia , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/parasitologia , Citotoxicidade Imunológica/imunologia , Modelos Animais de DoençasRESUMO
Malaria infections cause several systemic and severe single- or multi-organ pathologies, killing hundreds of thousands of people annually. Considering the existing widespread resistance of malaria parasites to anti-parasitic drugs and their high propensity to develop drug resistance, alternative strategies are required to manage malaria infections. Because malaria is a host immune response-driven disease, one approach is based on gaining a detailed understanding of the molecular and cellular processes that modulate malaria-induced innate and adaptive immune responses. Here, using a mouse cerebral malaria model and small-molecule inhibitors, we demonstrate that inhibiting MEK1/2, the upstream kinases of ERK1/2 signaling, alters multifactorial components of the innate and adaptive immune responses, controls parasitemia, and blocks pathogenesis. Specifically, MEK1/2 inhibitor treatment up-regulated B1 cell expansion, IgM production, phagocytic receptor expression, and phagocytic activity, enhancing parasite clearance by macrophages and neutrophils. Further, the MEK1/2 inhibitor treatment down-regulated pathogenic pro-inflammatory and helper T cell 1 (Th1) responses and up-regulated beneficial anti-inflammatory cytokine responses and Th2 responses. These inhibitor effects resulted in reduced granzyme B expression by T cells, chemokine and intracellular cell adhesion molecule 1 (ICAM-1) expression in the brain, and chemokine receptor expression by both myeloid and T cells. These bimodal effects of the MEK1/2 inhibitor treatment on immune responses contributed to decreased parasite biomass, organ inflammation, and immune cell recruitment, preventing tissue damage and death. In summary, we have identified several previously unrecognized immune regulatory processes through which a MEK1/2 inhibitor approach controls malaria parasitemia and mitigates pathogenic effects on host organs.
Assuntos
Antimaláricos/uso terapêutico , MAP Quinase Quinase 1/antagonistas & inibidores , MAP Quinase Quinase 2/antagonistas & inibidores , Malária Cerebral/tratamento farmacológico , Malária Falciparum/tratamento farmacológico , Plasmodium falciparum/efeitos dos fármacos , Inibidores de Proteínas Quinases/uso terapêutico , Imunidade Adaptativa/efeitos dos fármacos , Animais , Antimaláricos/farmacologia , Células da Medula Óssea/efeitos dos fármacos , Células da Medula Óssea/imunologia , Células da Medula Óssea/parasitologia , Células da Medula Óssea/patologia , Células Cultivadas , Técnicas de Cocultura , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/imunologia , Células Dendríticas/parasitologia , Células Dendríticas/patologia , Feminino , Flavonoides/farmacologia , Flavonoides/uso terapêutico , Imunidade Inata/efeitos dos fármacos , Células Matadoras Naturais/efeitos dos fármacos , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/parasitologia , Células Matadoras Naturais/patologia , MAP Quinase Quinase 1/metabolismo , MAP Quinase Quinase 2/metabolismo , Malária Cerebral/imunologia , Malária Cerebral/parasitologia , Malária Cerebral/patologia , Malária Falciparum/imunologia , Malária Falciparum/parasitologia , Malária Falciparum/patologia , Masculino , Camundongos Endogâmicos C57BL , Carga Parasitária , Parasitemia/prevenção & controle , Fagocitose/efeitos dos fármacos , Plasmodium falciparum/enzimologia , Plasmodium falciparum/imunologia , Plasmodium falciparum/isolamento & purificação , Inibidores de Proteínas Quinases/farmacologia , Proteínas de Protozoários/antagonistas & inibidores , Proteínas de Protozoários/metabolismo , Piridonas/farmacologia , Piridonas/uso terapêutico , Pirimidinonas/farmacologia , Pirimidinonas/uso terapêutico , Análise de SobrevidaRESUMO
Natural killer (NK) cells are known to be activated by Th1-type cytokines, such as IL-2, -12, or -18, and they secrete a large amount of IFN-γ that accelerates Th1-type responses. However, the roles of NK cells in Th2-type responses have remained unclear. Because IL-4 acts as an initiator of Th2-type responses, we examined the characteristics of NK cells in mice overexpressing IL-4. In this study, we report that IL-4 overexpression induces distinctive characteristics of NK cells (B220(high)/CD11b(low)/IL-18Rα(low)), which are different from mature conventional NK (cNK) cells (B220(low)/CD11b(high)/IL-18Rα(high)). IL-4 overexpression induces proliferation of tissue-resident macrophages, which contributes to NK cell proliferation via production of IL-15. These IL-4-induced NK cells (IL4-NK cells) produce higher levels of IFN-γ, IL-10, and GM-CSF, and exhibit high cytotoxicity compared with cNK cells. Furthermore, incubation of cNK cells with IL-15 and IL-4 alters their phenotype to that similar to IL4-NK cells. Finally, parasitic infection, which typically causes strong Th2-type responses, induces the development of NK cells with characteristics similar to IL4-NK cells. These IL4-NK-like cells do not develop in IL-4Rα KO mice by parasitic infection. Collectively, these results suggest a novel role of IL-4 in immune responses through the induction of the unique NK cells.
Assuntos
Citotoxicidade Imunológica , Interleucina-15/imunologia , Interleucina-4/imunologia , Células Matadoras Naturais/imunologia , Ativação Linfocitária , Infecções por Strongylida/imunologia , Animais , Antígeno CD11b/genética , Antígeno CD11b/imunologia , Proliferação de Células , Regulação da Expressão Gênica , Fator Estimulador de Colônias de Granulócitos e Macrófagos/genética , Fator Estimulador de Colônias de Granulócitos e Macrófagos/imunologia , Interferon gama/genética , Interferon gama/imunologia , Interleucina-10/genética , Interleucina-10/imunologia , Interleucina-15/genética , Interleucina-15/farmacologia , Interleucina-4/genética , Interleucina-4/farmacologia , Células Matadoras Naturais/efeitos dos fármacos , Células Matadoras Naturais/parasitologia , Antígenos Comuns de Leucócito/genética , Antígenos Comuns de Leucócito/imunologia , Macrófagos/imunologia , Macrófagos/parasitologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Nippostrongylus/imunologia , Nippostrongylus/patogenicidade , Receptores de Interleucina-18/genética , Receptores de Interleucina-18/imunologia , Receptores de Interleucina-4/deficiência , Receptores de Interleucina-4/genética , Receptores de Interleucina-4/imunologia , Transdução de Sinais , Infecções por Strongylida/genética , Infecções por Strongylida/parasitologiaRESUMO
The parasympathetic nervous system has a crucial role in immunomodulation of the vagus nerve, its structure provides a pathogen detection system, and a negative feedback to the immune system after the pathogenic agent has been eliminated. Amebiasis is a disease caused by the protozoan parasite Entamoeba histolytica, considered the third leading cause of death in the world. The rats are used as a natural resistance model to amoebic liver infection. The aim of this study is to analyze the interaction of Entamoeba histolytica with neutrophils, macrophages, and NK cells in livers of intact and vagotomized rats. Six groups were studied (n = 4): Intact (I), Intact + amoeba (IA), Sham (S), Sham + amoeba (SA), Vagotomized (V) and Vagotomized + amoeba (VA). Animals were sacrificed at 8 h post-inoculation of E. histolytica. Then, livers were obtained and fixed in 4% paraformaldehyde. Tissue liver slides were stained with H-E, PAS and Masson. The best development time for E. histolytica infection was at 8 h. Amoeba was identified with a monoclonal anti-220 kDa E. histolytica lectin. Neutrophils (N) were identified with rabbit anti-human neutrophil myeloperoxidase, macrophages (Mɸ) with anti-CD68 antibody and NK cells (NK) with anti-NK. Stomachs weight and liver glycogen were higher in V. Collagen increased in VA, whereas vascular and neutrophilic areas were decreased. There were fewer N, Mɸ, NK around the amoeba in the following order IA > SA > VA (p < 0.05 between IA and VA). In conclusion, these results suggest that the absence of parasympathetic innervation affects the participation of neutrophils, macrophages and NK cells in the innate immune response, apparently by parasympathetic inhibition on the cellular functions and probably for participation in sympathetic activity.
Assuntos
Entamoeba histolytica/imunologia , Imunidade Inata/fisiologia , Abscesso Hepático Amebiano/imunologia , Nervo Vago/fisiologia , Animais , Colágeno/metabolismo , Imunofluorescência , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/parasitologia , Cinética , Fígado/imunologia , Fígado/parasitologia , Fígado/patologia , Fígado/ultraestrutura , Macrófagos/imunologia , Macrófagos/parasitologia , Masculino , Camundongos , Microscopia Eletrônica de Transmissão , Neutrófilos/imunologia , Neutrófilos/parasitologia , Coelhos , Ratos , Ratos Wistar , Vagotomia , Nervo Vago/cirurgiaRESUMO
Patients with cystic echinococcosis (CE) can harbour cysts for years or even decades, apparently without effect of the immune system on the metacestode. Although several immune evasion mechanisms by echinococcal cysts have been described, it is unclear whether the human leucocyte antigen (HLA) system plays a role in the susceptibility or resistance to CE in humans. HLA-G molecules are known to exert a suppressive action on dendritic cells maturation and on natural killer (NK) cells functions, therefore hampering T-cell responses and NK cytolysis. HLA-G plays an important role in immune tolerance, is involved in foetus and in allotransplant tolerance, and may be involved in tumoral and viral immune evasion. In this study, we assessed the presence and levels of soluble HLA-G (sHLA-G) in patients with CE using a commercial ELISA kit to determine whether host's HLA-G may have a role in the course of human CE.
Assuntos
Equinococose/imunologia , Echinococcus/crescimento & desenvolvimento , Echinococcus/imunologia , Antígenos HLA-G/imunologia , Evasão da Resposta Imune , Adulto , Animais , Células Dendríticas/imunologia , Células Dendríticas/parasitologia , Equinococose/sangue , Equinococose/parasitologia , Echinococcus/genética , Ensaio de Imunoadsorção Enzimática , Feminino , Antígenos HLA-G/sangue , Humanos , Tolerância Imunológica , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/parasitologia , Masculino , Pessoa de Meia-Idade , Linfócitos T/imunologia , Linfócitos T/parasitologia , Adulto JovemRESUMO
Cutaneous leishmaniasis (CL) is an important public health issue worldwide. The control of Leishmania infection depends on cellular immune mechanisms, and the inflammatory response may contribute to pathogenesis. A beneficial role of CD8(+) T lymphocytes has been proposed; nevertheless, other studies suggest a cytotoxic role of CD8(+) T lymphocytes involved in tissue damage, showing controversial role of these cells. The goal of the current study was to understand the immunopathology of CL and determine the profile of cytotoxic cells--such as CD4(+) T, natural killer and natural killer T cells--that might be involved in triggering immunological mechanisms, and may lead to cure or disease progression. The frequencies of cytotoxic cell populations in peripheral blood, obtained from patients with active disease, during treatment and after clinical healing, were assessed by flow cytometry. Cytotoxicity could not be related to a deleterious role in Leishmania braziliensis infection, as patients with active CL showed similar percentages of degranulation to healthy individuals (HI). Cured patients exhibited a lower percentage of degranulating cells, which may be due to a downregulation of the immune response. The understanding of the immunopathological mechanisms involved in CL and the commitment of cytotoxic cells enables improvements in therapeutic strategies.
Assuntos
Leishmaniose Cutânea/imunologia , Adulto , Antiprotozoários/uso terapêutico , Contagem de Linfócito CD4 , Degranulação Celular , Células Cultivadas , Citotoxicidade Imunológica , Feminino , Humanos , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/parasitologia , Leishmania braziliensis/imunologia , Leishmaniose Cutânea/tratamento farmacológico , Masculino , Meglumina/uso terapêutico , Antimoniato de Meglumina , Pessoa de Meia-Idade , Células T Matadoras Naturais/imunologia , Células T Matadoras Naturais/parasitologia , Compostos Organometálicos/uso terapêutico , Adulto JovemRESUMO
Post-kala-azar dermal leishmaniasis (PKDL) is a chronic dermal complication that occurs usually after recovery from visceral leishmaniasis (VL). The disease manifests into macular, papular and/or nodular clinical types with mono- or polymorphic presentations. Here, we investigated differences in immunological response between these two distinct clinical forms in Indian PKDL patients. Peripheral blood mononuclear cells of PKDL and naive individuals were exposed in vitro to total soluble Leishmania antigen (TSLA). The proliferation index was evaluated using an enzyme-linked immunosorbent assay (ELISA)-based lymphoproliferative assay. Cytokines and granzyme B levels were determined by cytometric bead array. Parasite load in tissue biopsy samples of PKDL was quantified by quantitative polymerase chain reaction (qPCR). The proportion of different lymphoid subsets in peripheral blood and the activated T cell population were estimated using flow cytometry. The study demonstrated heightened cellular immune responses in the polymorphic PKDL group compared to the naive group. The polymorphic group showed significantly higher lymphoproliferation, increased cytokines and granzyme B levels upon TSLA stimulation, and a raised proportion of circulating natural killer (NK) T cells against naive controls. Furthermore, the polymorphic group showed a significantly elevated proportion of activated CD4(+) and CD8(+) T cells upon in-vitro TSLA stimulation. Thus, the polymorphic variants showed pronounced cellular immunity while the monomorphic form demonstrated a comparatively lower cellular response. Additionally, the elevated level of both activated CD4(+) and CD8(+) T cells, coupled with high granzyme B secretion upon in-vitro TSLA stimulation, indicated the role of cytotoxic cells in resistance to L. donovani infection in polymorphic PKDL.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Células Matadoras Naturais/imunologia , Leishmaniose Cutânea/imunologia , Leishmaniose Visceral/imunologia , Pele/imunologia , Adolescente , Adulto , Antígenos de Protozoários/farmacologia , Linfócitos T CD4-Positivos/parasitologia , Linfócitos T CD4-Positivos/patologia , Linfócitos T CD8-Positivos/parasitologia , Linfócitos T CD8-Positivos/patologia , Proliferação de Células , Citocinas/genética , Citocinas/imunologia , Citotoxicidade Imunológica , Feminino , Citometria de Fluxo , Expressão Gênica , Granzimas/genética , Granzimas/imunologia , Humanos , Imunofenotipagem , Índia , Células Matadoras Naturais/parasitologia , Células Matadoras Naturais/patologia , Leishmania donovani/imunologia , Leishmania donovani/patogenicidade , Leishmaniose Cutânea/diagnóstico , Leishmaniose Cutânea/parasitologia , Leishmaniose Cutânea/patologia , Leishmaniose Visceral/diagnóstico , Leishmaniose Visceral/parasitologia , Leishmaniose Visceral/patologia , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/parasitologia , Leucócitos Mononucleares/patologia , Ativação Linfocitária , Masculino , Carga Parasitária , Cultura Primária de Células , Pele/parasitologia , Pele/patologiaRESUMO
Tissue-infiltrating Ly6C(hi) monocytes play diverse roles in immunity, ranging from pathogen killing to immune regulation. How and where this diversity of function is imposed remains poorly understood. Here we show that during acute gastrointestinal infection, priming of monocytes for regulatory function preceded systemic inflammation and was initiated prior to bone marrow egress. Notably, natural killer (NK) cell-derived IFN-γ promoted a regulatory program in monocyte progenitors during development. Early bone marrow NK cell activation was controlled by systemic interleukin-12 (IL-12) produced by Batf3-dependent dendritic cells (DCs) in the mucosal-associated lymphoid tissue (MALT). This work challenges the paradigm that monocyte function is dominantly imposed by local signals after tissue recruitment, and instead proposes a sequential model of differentiation in which monocytes are pre-emptively educated during development in the bone marrow to promote their tissue-specific function.
Assuntos
Células da Medula Óssea/imunologia , Células Dendríticas/imunologia , Mucosa Intestinal/imunologia , Células Matadoras Naturais/imunologia , Leucócitos Mononucleares/imunologia , Toxoplasma/imunologia , Toxoplasmose/imunologia , Animais , Antígenos Ly/metabolismo , Fatores de Transcrição de Zíper de Leucina Básica/genética , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Células da Medula Óssea/parasitologia , Diferenciação Celular , Células Cultivadas , Interferon gama/metabolismo , Interleucina-12/genética , Interleucina-12/metabolismo , Mucosa Intestinal/parasitologia , Células Matadoras Naturais/parasitologia , Leucócitos Mononucleares/parasitologia , Ativação Linfocitária , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Modelos Imunológicos , Especificidade de Órgãos/imunologia , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismoRESUMO
Early interactions between natural killer (NK) and dendritic cells (DC) shape the immune response at the frontier of innate and adaptive immunity. Activated NK cells participate in maturation or deletion of DCs that remain immature. We previously demonstrated that infection with a high virulence (HV) population of the protozoan parasite Trypanosoma cruzi downmodulates DC maturation and T-cell activation capacity. Here, we evaluated the role of NK cells in regulating the maturation level of DCs. Shortly after infection with HV T. cruzi, DCs in poor maturation status begin to accumulate in mouse spleen. Although infection induces NK cell cytotoxicity and cytokine production, NK cells from mice infected with HV T. cruzi exhibit reduced ability to lyse and fail to induce maturation of bone marrow-derived immature DCs (iDCs). NK-mediated lysis of iDCs is restored by in vitro blockade of the IL-10 receptor during NK-DC interaction or when NK cells are obtained from T. cruzi-infected IL-10 knockout mice. These results suggest that infection with a virulent T. cruzi strain alters NK cell-mediated regulation of the adaptive immune response induced by DCs. This regulatory circuit where IL-10 appears to participate might lead to parasite persistence but can also limit the induction of a vigorous tissue-damaging T-cell response.
Assuntos
Doença de Chagas/imunologia , Células Dendríticas/imunologia , Células Matadoras Naturais/imunologia , Linfócitos T/imunologia , Trypanosoma cruzi/imunologia , Animais , Anticorpos Bloqueadores/administração & dosagem , Diferenciação Celular , Células Cultivadas , Citotoxicidade Imunológica/efeitos dos fármacos , Citotoxicidade Imunológica/genética , Células Dendríticas/parasitologia , Interleucina-10/genética , Células Matadoras Naturais/parasitologia , Ativação Linfocitária , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C3H , Camundongos Knockout , Receptores de Interleucina-10/imunologia , Trypanosoma cruzi/patogenicidade , VirulênciaRESUMO
Cryptosporidium spp. that develop in intestinal epithelial cells are responsible for the diarrhoeal disease cryptosporidiosis, which is common in humans of all ages and in neonatal livestock. Following infection, parasite reproduction increases for a number of days before it is blunted and then impeded by innate and adaptive immune responses. Immunocompromised hosts often cannot establish strong immunity and develop chronic infections that can lead to death. Few drugs consistently inhibit parasite reproduction in the host, and chemotherapy might be ineffective in immunodeficient hosts. Future options for prevention or treatment of cryptosporidiosis might include vaccines or recombinant immunological molecules, but this will probably require a better understanding of both the mucosal immune system and intestinal immune responses to the parasite.
Assuntos
Imunidade Adaptativa , Criptosporidiose/tratamento farmacológico , Cryptosporidium parvum/efeitos dos fármacos , Diarreia/tratamento farmacológico , Imunidade Inata , Imunidade nas Mucosas , Animais , Anticorpos Neutralizantes/administração & dosagem , Anticorpos Neutralizantes/imunologia , Anticorpos Neutralizantes/uso terapêutico , Anticorpos Antiprotozoários/biossíntese , Anticorpos Antiprotozoários/imunologia , Linfócitos B/efeitos dos fármacos , Linfócitos B/imunologia , Linfócitos B/parasitologia , Criptosporidiose/complicações , Criptosporidiose/imunologia , Criptosporidiose/parasitologia , Criptosporidiose/prevenção & controle , Cryptosporidium parvum/imunologia , Citocinas/biossíntese , Diarreia/etiologia , Diarreia/imunologia , Diarreia/parasitologia , Diarreia/prevenção & controle , Humanos , Hospedeiro Imunocomprometido , Imunoterapia , Intestinos/efeitos dos fármacos , Intestinos/imunologia , Intestinos/parasitologia , Células Matadoras Naturais/efeitos dos fármacos , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/parasitologia , Vacinas Protozoárias/administração & dosagem , Vacinas Protozoárias/uso terapêutico , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia , Linfócitos T/parasitologiaRESUMO
The neuro-immune network, in which the vagus nerve is involved, provides feedback between its afferent branches for signalling central nervous system from sites of injury through cytokines and its efferent branches, which release acetylcholine, an anti-inflammatory neurotransmitter. For gain insight into the parasympathetic mechanisms participating in the inflammatory response in the liver, we studied the effects of a vagotomy on the innate immune response in hamsters with amoebic liver abscess. At 7 days post-infection, compared to the control, liver parasympathectomy resulted in a larger abscess size, a greater production of collagen fibres, fewer trophozoites, increased serum levels of IL-10 and IFN-γ and increased numbers of IL-10 and IFN-γ-positive cells in situ, with no change in the number of macrophages and NK cells. Data indicate that the vagotomy disrupted the inflammatory response, causing an increase in the response against infection, then could favour the innervation of the liver by the sympathetic nervous system and would then take the control of the immune response by stimulating the conversion of macrophages to epithelioid cells; and through increased IL-10 production would induce the hepatic stellar cells to become myofibroblast collagen producer cells, thus forming a barrier of collagen and blocking trophozoite migration.
Assuntos
Interferon gama/imunologia , Interleucina-10/imunologia , Células Matadoras Naturais/imunologia , Abscesso Hepático Amebiano/imunologia , Abscesso Hepático Amebiano/fisiopatologia , Fígado/imunologia , Fígado/fisiopatologia , Macrófagos/imunologia , Miofibroblastos/imunologia , Neuroimunomodulação , Fator de Necrose Tumoral alfa/imunologia , Vagotomia , Nervo Vago/imunologia , Nervo Vago/fisiopatologia , Nervo Vago/cirurgia , Animais , Cricetinae , Ensaio de Imunoadsorção Enzimática , Imuno-Histoquímica , Células Matadoras Naturais/parasitologia , Fígado/parasitologia , Fígado/ultraestrutura , Abscesso Hepático Amebiano/parasitologia , Macrófagos/parasitologia , Masculino , Miofibroblastos/parasitologia , Neuroimunomodulação/fisiologiaRESUMO
Previous studies have implicated T cell production of IL-17 in resistance to Toxoplasma gondii as well as the development of immune-mediated pathology during this infection. Analysis of C57BL/6 and C57BL/6 RAG(-/-) mice challenged with T. gondii-identified NK cells as a major innate source of IL-17. The ability of soluble Toxoplasma Ag to stimulate NK cells to produce IL-17 was dependent on the presence of accessory cells and the production of IL-6, IL-23, and TGF-beta. In contrast, these events were inhibited by IL-2, IL-15, and IL-27. Given that IL-6 was one of the most potent enhancers of NK cell production of IL-17, further studies revealed that only a subset of NK cells expressed both chains of the IL-6R, IL-6 upregulated expression of the Th17-associated transcription factor RORgammat, and that IL-6(-/-) mice challenged with T. gondii had a major defect in NK cell production of IL-17. Together, these data indicate that many of the same cytokines that regulate Th17 cells are part of a conserved pathway that also control innate production of IL-17 and identify a major role for IL-6 in the regulation of NK cell responses.