RESUMO
The liver fluke, Fasciola hepatica, infects a wide range of mammals including humans and leads to chronic disease. Like other helminths, F. hepatica migrates and survives in the host tissues after penetrating the intestinal wall to enter the peritoneal cavity, and then migrates through the liver before finally inhabiting the bile ducts. To avoid the antihelminthic immune response during migration, F. hepatica releases excretory-secretory products (FhESP) that exert various immunomodulatory effects, such as alternative macrophage activation or programmed cell death induction. Here, we describe the currently available techniques for studying macrophage activation and apoptotic cell death triggered by purified FhESP originating from the adult F. hepatica fluke.
Assuntos
Antígenos de Helmintos/imunologia , Fasciola hepatica/imunologia , Imunomodulação/imunologia , Macrófagos/imunologia , Animais , Apoptose/imunologia , Feminino , Imunidade/imunologia , Macrófagos/parasitologia , Camundongos , Camundongos Endogâmicos BALB CRESUMO
The excretory-secretory products released by the liver fluke Fasciola hepatica (FhESP) are in close contact with the immune system and have different immunomodulatory effects associated with the parasite virulence. The control of the early immune response is crucial for the establishment of the fluke in the host. Related to this, eosinophils (Eo) are implicated as effector cells in helminthic infections, and the induction of Eo apoptosis has been demonstrated to be a remarkable immunoevasion mechanism induced by the parasite. In this chapter, we describe different techniques to assay Eo apoptosis triggered by FhESP as well as the mechanisms involved in this phenomenon.
Assuntos
Antígenos de Helmintos/imunologia , Apoptose/imunologia , Eosinófilos/imunologia , Fasciola hepatica/imunologia , Animais , Fasciolíase/imunologia , Fasciolíase/parasitologia , Imunomodulação/imunologia , Contagem de Leucócitos/métodos , Masculino , Ratos , Ratos WistarRESUMO
Despite worldwide prevalence of superficial mycoses, the immune response in dermatophytosis has scarcely been investigated. In this study, we developed a model of superficial skin infection in C57BL/6 mice with Microsporum canis, a highly prevalent human pathogen. This model mimics mild inflammatory human dermatophytosis, characterized by neutrophil recruitment and fungal invasion limited to the epidermis and exhibits the establishment of a specific T helper type 17 immune response during infection. By using IL-17RA- or IL-17A/F-deficient mice we showed that, in the absence of a functional IL-17 pathway, M. canis extensively colonizes the epidermis and promotes an exaggerated skin inflammation and a shift to an IFN-γ-mediated (T helper type 1) response. IL-17 signaling was not involved in neutrophil influx to skin or fungal invasion to deeper tissues. Finally, this study shows that skin langerin-expressing cells contribute to the antifungal T helper type 17 response in vivo. In conclusion, these data directly show a dual function of IL-17 cytokines in dermatophytosis by controlling superficial infection and down-modulating a T helper type 1 antifungal response.
Assuntos
Interações Hospedeiro-Patógeno/imunologia , Microsporum/imunologia , Transdução de Sinais/imunologia , Células Th17/imunologia , Tinha/imunologia , Animais , Modelos Animais de Doenças , Epiderme/imunologia , Epiderme/microbiologia , Epiderme/patologia , Humanos , Interleucina-17/genética , Interleucina-17/imunologia , Interleucina-17/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microsporum/patogenicidade , Infiltração de Neutrófilos/imunologia , Receptores de Interleucina-17/genética , Receptores de Interleucina-17/imunologia , Receptores de Interleucina-17/metabolismo , Células Th17/metabolismo , Tinha/microbiologia , Tinha/patologiaRESUMO
Immunomodulatory properties have been described for Fasciola hepatica excretory-secretory products (FhESP), with their interaction with the innate immune cells being crucial during the early stages of infection. Previously, we demonstrated that FhESP induce eosinophil apoptosis. In this work, the ability of FhESP to induce apoptosis of peritoneal macrophages was evaluated. These parasite products were observed to induce apoptosis in peritoneal macrophages stimulated in vitro with FhESP, as well as in cells recovered from infected mice. The ability of FhESP to modify the viability of macrophages by apoptosis induction may constitute a crucial event for extending its survival in the host.
Assuntos
Apoptose/imunologia , Fasciola hepatica/imunologia , Fasciolíase/imunologia , Macrófagos Peritoneais/imunologia , Animais , Feminino , Citometria de Fluxo , Imunidade Celular/imunologia , Macrófagos Peritoneais/parasitologia , Camundongos , Camundongos Endogâmicos BALB CRESUMO
Experimental Cryptococcus neoformans infection in rats has been shown to have similarities with human cryptococcosis, because as in healthy humans, rats can effectively contain cryptococcal infection. Moreover, it has been shown that eosinophils are components of the immune response to C. neoformans infections. In a previous in vitro study, we demonstrated that rat peritoneal eosinophils phagocytose opsonized live yeasts of C. neoformans, thereby triggering their activation, as indicated by the up-regulation of MHC and co-stimulatory molecules and the increase in interleukin-12, tumour necrosis factor-α and interferon-γ production. Furthermore, this work demonstrated that C. neoformans-specific CD4(+) and CD8(+) T lymphocytes cultured with these activated C. neoformans-pulsed eosinophils proliferated, and produced important amounts of T helper type 1 (Th1) cytokines in the absence of Th2 cytokine synthesis. In the present in vivo study, we have shown that C. neoformans-pulsed eosinophils are also able to migrate into lymphoid organs to present C. neoformans antigens, thereby priming naive and re-stimulating infected rats to induce T-cell and B-cell responses against infection with the fungus. Furthermore, the antigen-specific immune response induced by C. neoformans-pulsed eosinophils, which is characterized by the development of a Th1 microenvironment with increased levels of NO synthesis and C. neoformans-specific immunoglobulin production, was demonstrated to be able to protect rats against subsequent infection with fungus. In summary, the present work demonstrates that eosinophils act as antigen-presenting cells for the fungal antigen, hence initiating and modulating a C. neoformans-specific immune response. Finally, we suggest that C. neoformans-loaded eosinophils might participate in the protective immune response against these fungi.
Assuntos
Criptococose/imunologia , Cryptococcus neoformans/imunologia , Citocinas/imunologia , Eosinófilos/imunologia , Ativação Linfocitária/imunologia , Células Th1/imunologia , Animais , Apresentação de Antígeno/imunologia , Antígenos de Fungos/imunologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Movimento Celular/imunologia , Técnicas de Cocultura , Interferon gama/biossíntese , Interferon gama/imunologia , Interferon gama/metabolismo , Interleucinas/biossíntese , Interleucinas/imunologia , Masculino , Óxido Nítrico/biossíntese , Óxido Nítrico/imunologia , Ratos , Ratos Wistar , Fator de Necrose Tumoral alfa/biossíntese , Fator de Necrose Tumoral alfa/imunologiaRESUMO
Fasciola hepatica releases excretory-secretory products (FhESP), and immunomodulatory properties have been described for the carbohydrates present in these parasite products. The interaction of FhESP with the innate immune cells, such as macrophages, is crucial in the early stage of infection. In this work we observed that peritoneal macrophages from naive BALB/c mice stimulated in vitro with FhESP presented: an increased arginase activity as well as Arginase I expression, and high levels of transforming growth factor-ß and interleukin-10. A similar macrophage population was also observed in the peritoneum of infected mice. A partial inhibition of the immunomodulatory effects described above was observed when macrophages were pre-incubated with Mannan, anti-mannose receptor, Laminarin or anti-Dectin-1, and then stimulated with FhESP. In addition, we observed a partial inhibition of these effects in macrophages obtained from mice that were intraperitoneally injected with Mannan or Laminarin before being infected. Taken together, these results suggest the participation of at least two C-type lectin receptors, mannose receptor and Dectin-1, in the interaction of FhESP with macrophages, which allows this parasite to induce immunoregulatory effects on these important innate immune cells and may constitute a crucial event for extending its survival in the host.
Assuntos
Antígenos de Helmintos/imunologia , Fasciola hepatica/imunologia , Fatores Imunológicos/imunologia , Lectinas Tipo C/imunologia , Macrófagos/imunologia , Animais , Arginase/metabolismo , Western Blotting , Células Cultivadas , Eletroforese em Gel de Poliacrilamida , Interleucina-10/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Fator de Crescimento Transformador beta/imunologia , Regulação para CimaRESUMO
Our previous studies showed that the subcutaneous pretreatment of rats with heat killed cells of Cryptococcus neoformans (HKC) emulsified in complete Freund adjuvant (CFA) promotes protection against an intraperitoneal challenge with viable C. neoformans. In this model, an appropriate activation of adherent peritoneal cells after antigenic treatment is very important for the control of the infection. Here, we investigated the immune response developed in spleen and lymphatic nodes as a result of treatment with HKC-CFA, which might also contribute in the protective phenomenon of this treatment against cryptococcal infection. The results show that, compared with adjuvant alone, rats which received treatment with HKC-CFA presented a greater activation of adherent splenic cells, with up-regulation of major histocompatibility complex class II (MHC II) and CD86 expression and secretion of anticryptococcal metabolites. Furthermore, this treatment also induced an increase in the blastogenic response and the secretion of Th1 and Th2 cytokines by spleen cells in comparison with cells from CFA-phosphate-buffered saline (PBS) treated rats. On the other hand, lymph node cells from animals treated with HKC-CFA presented a rise in the expression of MHCII but not of CD86 with respect to control cells from rats treated with CFA-PBS. These cells also showed a high proliferative response and secretion of Th1-related cytokines, interleukin (IL)-12 and tumor necrosis factor (TNF). These results show that treatment of rats with HKC-CFA is able to induce an early immune response in secondary lymphoid organs, which may contribute to the protective effect induced by this treatment.
Assuntos
Criptococose/prevenção & controle , Imunidade Celular , Linfonodos/imunologia , Linfócitos/imunologia , Baço/imunologia , Vacinação , Vacinas de Produtos Inativados/administração & dosagem , Animais , Antígenos de Fungos/imunologia , Antígeno B7-2/biossíntese , Antígeno B7-2/imunologia , Adesão Celular/imunologia , Proliferação de Células , Células Cultivadas , Criptococose/imunologia , Criptococose/metabolismo , Cryptococcus neoformans/crescimento & desenvolvimento , Cryptococcus neoformans/imunologia , Feminino , Adjuvante de Freund/administração & dosagem , Genes MHC da Classe II/imunologia , Temperatura Alta , Interleucina-12/biossíntese , Interleucina-12/imunologia , Linfonodos/citologia , Linfonodos/microbiologia , Ativação Linfocitária , Linfócitos/microbiologia , Ratos , Ratos Wistar , Baço/citologia , Baço/microbiologia , Equilíbrio Th1-Th2 , Fator de Necrose Tumoral alfa/biossíntese , Fator de Necrose Tumoral alfa/imunologiaRESUMO
Dermatophytic mycetoma is an extremely rare subcutaneous mycosis. Here, we report the case of a 6-year-old girl with clinical, histologic, and mycologic findings consistent with a mycetoma of the scalp caused by Microsporum canis. To our knowledge, this is the first report showing the immunologic and immunogenetic features of a patient with a recalcitrant dermatophytic mycetoma.
Assuntos
Microsporum/isolamento & purificação , Micetoma/diagnóstico , Micetoma/patologia , Couro Cabeludo/microbiologia , Couro Cabeludo/patologia , Antifúngicos/uso terapêutico , Criança , Feminino , Genótipo , Histocitoquímica , Humanos , Microscopia , Microsporum/genética , Tipagem Molecular , Micetoma/microbiologia , Micetoma/terapia , Técnicas de Tipagem Micológica , Reação em Cadeia da PolimeraseRESUMO
Experimental Cryptococcus neoformans infection in rats has been shown to have similarities with human cryptococcosis, revealing a strong granulomatous response and a low susceptibility to dissemination. Moreover, it has been shown that eosinophils are components of the inflammatory response to C. neoformans infections. In this in vitro study, we demonstrated that rat peritoneal eosinophils phagocytose opsonized live yeasts of C. neoformans, and that the phenomenon involves the engagement of FcγRII and CD18. Moreover, our results showed that the phagocytosis of opsonized C. neoformans triggers eosinophil activation, as indicated by (i) the up-regulation of major histocompatibility complex (MHC) class I, MHC class II and costimulatory molecules, and (ii) an increase in interleukin (IL)-12, tumour necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) production. However, nitric oxide (NO) and hydrogen peroxide (H(2) O(2) ) synthesis by eosinophils was down-regulated after interaction with C. neoformans. Furthermore, this work demonstrated that CD4(+) and CD8(+) T lymphocytes isolated from spleens of infected rats and cultured with C. neoformans-pulsed eosinophils proliferate in an MHC class II- and class I-dependent manner, respectively, and produce important amounts of T-helper 1 (Th1) type cytokines, such as TNF-α and IFN-γ, in the absence of T-helper 2 (Th2) cytokine synthesis. In summary, the present study demonstrates that eosinophils act as fungal antigen-presenting cells and suggests that C. neoformans-loaded eosinophils might participate in the adaptive immune response.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Criptococose/imunologia , Cryptococcus neoformans/imunologia , Eosinófilos/imunologia , Células Th1/imunologia , Imunidade Adaptativa , Animais , Apresentação de Antígeno , Células Apresentadoras de Antígenos/imunologia , Células Apresentadoras de Antígenos/fisiologia , Criptococose/microbiologia , Eosinófilos/fisiologia , Humanos , Interferon gama/metabolismo , Masculino , Fagocitose , Ratos , Ratos Wistar , Células Th1/metabolismo , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Fasciola hepatica is a helminth trematode that migrates through the host tissues until reaching bile ducts where it becomes an adult. During its migration the parasite releases different excretory-secretory products (ESP), which are in contact with the immune system. In this study, we focused on the effect of ESP on the maturation and function of murine bone marrow derived-dendritic cells (DC). We found that the treatment of DC with ESP failed to induce a classical maturation of these cells, since ESP alone did not activate DC to produce any cytokines, although they impaired the ability of DC to be activated by TLR ligands and also their capacity to stimulate an allospecific response. In addition, using an in vitro ovalbumin peptide-restricted priming assay, ESP-treated DC exhibited a capacity to drive Th2 and regulatory T cell (Treg) polarization of CD4(+) cells from DO11.10 transgenic mice. This was characterized by increased IL-4, IL-5, IL-10 and TGF-beta production and the expansion of CD4(+)CD25(+)Foxp3(+) cells. Our results support the hypothesis that ESP from F. hepatica modulate the maturation and function of DC as part of a generalized immunosuppressive mechanism that involves a bias towards a Th2 response and Treg development.