RESUMEN
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.
Asunto(s)
Antígenos Helmínticos/inmunología , Fasciola hepatica/inmunología , Inmunomodulación/inmunología , Macrófagos/inmunología , Animales , Apoptosis/inmunología , Femenino , Inmunidad/inmunología , Macrófagos/parasitología , Ratones , Ratones Endogámicos BALB CRESUMEN
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.
Asunto(s)
Antígenos Helmínticos/inmunología , Apoptosis/inmunología , Eosinófilos/inmunología , Fasciola hepatica/inmunología , Animales , Fascioliasis/inmunología , Fascioliasis/parasitología , Inmunomodulación/inmunología , Recuento de Leucocitos/métodos , Masculino , Ratas , Ratas WistarRESUMEN
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.
Asunto(s)
Interacciones Huésped-Patógeno/inmunología , Microsporum/inmunología , Transducción de Señal/inmunología , Células Th17/inmunología , Tiña/inmunología , Animales , Modelos Animales de Enfermedad , Epidermis/inmunología , Epidermis/microbiología , Epidermis/patología , Humanos , Interleucina-17/genética , Interleucina-17/inmunología , Interleucina-17/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Microsporum/patogenicidad , Infiltración Neutrófila/inmunología , Receptores de Interleucina-17/genética , Receptores de Interleucina-17/inmunología , Receptores de Interleucina-17/metabolismo , Células Th17/metabolismo , Tiña/microbiología , Tiña/patologíaRESUMEN
Fasciola hepatica excretory-secretory products (FhESP) induce immunomodulatory effects on macrophages. Previously, we demonstrated that these effects are dependent on Dectin-1. Therefore, the aim of this study was to determine how this affects the CD4 T-cells immune response. We observed that FhESP induce an increased expression of PD-L2 in macrophages via Dectin-1. Furthermore, in co-cultures with CD4 T-cell we observed a suppressive effect on proliferative response, down-modulation of IFN-γ and up-modulation of IL-10 via Dectin-1 on macrophages. These results suggest that FhESP induce T-cell anergy via selective up-regulation of PD-L2 expression on macrophages in a Dectin-1 dependent way.
Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Anergia Clonal/inmunología , Fasciola hepatica/inmunología , Macrófagos/inmunología , Proteína 2 Ligando de Muerte Celular Programada 1/metabolismo , Animales , Antígenos Helmínticos/inmunología , Fascioliasis/inmunología , Fascioliasis/parasitología , Inmunomodulación/inmunología , Lectinas Tipo C/metabolismo , Masculino , Ratones , Ratones Endogámicos BALB CRESUMEN
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.
Asunto(s)
Apoptosis/inmunología , Fasciola hepatica/inmunología , Fascioliasis/inmunología , Macrófagos Peritoneales/inmunología , Animales , Femenino , Citometría de Flujo , Inmunidad Celular/inmunología , Macrófagos Peritoneales/parasitología , Ratones , Ratones Endogámicos BALB CRESUMEN
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.
Asunto(s)
Criptococosis/inmunología , Cryptococcus neoformans/inmunología , Citocinas/inmunología , Eosinófilos/inmunología , Activación de Linfocitos/inmunología , Células TH1/inmunología , Animales , Presentación de Antígeno/inmunología , Antígenos Fúngicos/inmunología , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Movimiento Celular/inmunología , Técnicas de Cocultivo , Interferón gamma/biosíntesis , Interferón gamma/inmunología , Interferón gamma/metabolismo , Interleucinas/biosíntesis , Interleucinas/inmunología , Masculino , Óxido Nítrico/biosíntesis , Óxido Nítrico/inmunología , Ratas , Ratas Wistar , Factor de Necrosis Tumoral alfa/biosíntesis , Factor de Necrosis Tumoral alfa/inmunologíaRESUMEN
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.
Asunto(s)
Antígenos Helmínticos/inmunología , Fasciola hepatica/inmunología , Factores Inmunológicos/inmunología , Lectinas Tipo C/inmunología , Macrófagos/inmunología , Animales , Arginasa/metabolismo , Western Blotting , Células Cultivadas , Electroforesis en Gel de Poliacrilamida , Interleucina-10/inmunología , Ratones , Ratones Endogámicos BALB C , Factor de Crecimiento Transformador beta/inmunología , Regulación hacia ArribaRESUMEN
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.
Asunto(s)
Criptococosis/prevención & control , Inmunidad Celular , Ganglios Linfáticos/inmunología , Linfocitos/inmunología , Bazo/inmunología , Vacunación , Vacunas de Productos Inactivados/administración & dosificación , Animales , Antígenos Fúngicos/inmunología , Antígeno B7-2/biosíntesis , Antígeno B7-2/inmunología , Adhesión Celular/inmunología , Proliferación Celular , Células Cultivadas , Criptococosis/inmunología , Criptococosis/metabolismo , Cryptococcus neoformans/crecimiento & desarrollo , Cryptococcus neoformans/inmunología , Femenino , Adyuvante de Freund/administración & dosificación , Genes MHC Clase II/inmunología , Calor , Interleucina-12/biosíntesis , Interleucina-12/inmunología , Ganglios Linfáticos/citología , Ganglios Linfáticos/microbiología , Activación de Linfocitos , Linfocitos/microbiología , Ratas , Ratas Wistar , Bazo/citología , Bazo/microbiología , Balance Th1 - Th2 , Factor de Necrosis Tumoral alfa/biosíntesis , Factor de Necrosis Tumoral alfa/inmunologíaRESUMEN
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.
Asunto(s)
Microsporum/aislamiento & purificación , Micetoma/diagnóstico , Micetoma/patología , Cuero Cabelludo/microbiología , Cuero Cabelludo/patología , Antifúngicos/uso terapéutico , Niño , Femenino , Genotipo , Histocitoquímica , Humanos , Microscopía , Microsporum/genética , Tipificación Molecular , Micetoma/microbiología , Micetoma/terapia , Técnicas de Tipificación Micológica , Reacción en Cadena de la PolimerasaRESUMEN
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.
Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Criptococosis/inmunología , Cryptococcus neoformans/inmunología , Eosinófilos/inmunología , Células TH1/inmunología , Inmunidad Adaptativa , Animales , Presentación de Antígeno , Células Presentadoras de Antígenos/inmunología , Células Presentadoras de Antígenos/fisiología , Criptococosis/microbiología , Eosinófilos/fisiología , Humanos , Interferón gamma/metabolismo , Masculino , Fagocitosis , Ratas , Ratas Wistar , Células TH1/metabolismo , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
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.
Asunto(s)
Células Dendríticas/inmunología , Fasciola hepatica/inmunología , Proteínas del Helminto/fisiología , Tolerancia Inmunológica , Células Mieloides/inmunología , Animales , Citocinas/biosíntesis , Femenino , Factores de Transcripción Forkhead/análisis , Interleucina-10/biosíntesis , Interleucina-4/biosíntesis , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Factor 88 de Diferenciación Mieloide/fisiología , Células Th2/inmunología , Receptores Toll-Like/fisiologíaRESUMEN
Previous studies in our laboratory have shown that the subcutaneous pretreatment of rats with heat-killed cells (HKC) of Cryptococcus neoformans emulsified in complete Freund adjuvant (CFA) promotes protective immunity against an intraperitoneal challenge with C. neoformans. In contrast, subcutaneous treatment with the capsular polysaccharide (PSC) emulsified in CFA exacerbates the cryptococcal infection. The purpose of this study was to analyze the mechanisms involved in these phenomena. Adherent peritoneal cells from rats treated with HKC-CFA showed upregulated ED2, CD80, and CD86 expression; an increase in the level of production of anticryptococcal metabolites; and the enhanced production of interleukin-12 (IL-12) in comparison with the findings for cells from rats treated with CFA-phosphate-buffered saline (PBS). Adherent peritoneal cells from rats treated with PSC-CFA, however, also presented upregulated ED2, CD80, and CD86 expression compared to the level of expression for peritoneal cells from controls, but these cells showed an increase in arginase activity and decreased levels of production of IL-12 and tumor necrosis factor (TNF) compared with the activity and levels of production by peritoneal cells from CFA-PBS-treated rats. In addition, treatment with HKC-CFA resulted in a rise in the phagocytic and anticryptococcal activities of adherent peritoneal cells compared to those for control rats. However, adherent peritoneal cells from rats treated with PSC-CFA presented a reduction in anticryptococcal activity in comparison with that for cells from animals treated with CFA-PBS. These results show the differential activation between adherent peritoneal cells from HKC-CFA- and PSC-CFA-treated rats, with this differential activation at the primary site of infection possibly being responsible, at least in part, for the phenomena of protection and exacerbation observed in our model.
Asunto(s)
Antígenos Fúngicos/inmunología , Cryptococcus neoformans/inmunología , Macrófagos Peritoneales/inmunología , Polisacáridos/inmunología , Animales , Antígeno B7-1/biosíntesis , Antígeno B7-2/biosíntesis , Femenino , Interleucina-12/biosíntesis , Fagocitosis , Ratas , Factor de Necrosis Tumoral alfa/biosíntesis , Regulación hacia ArribaRESUMEN
Eosinophils (Eo) are typically associated with immune response to helminth. Previously, we demonstrated that excretory-secretory products (ESP) from Fasciola hepatica induce eosinophil apoptosis by a caspase-dependent mechanism. In this study, we observed that ESP caused mitochondrial-membrane depolarization of eosinophils leading to the release of cytochrome c. Also, ESP induced an increase in the reactive oxygen species (ROS) production, which preceded the mitochondrial injury. We found a significant rise in hydrogen peroxide, but not in the anion superoxide levels. Furthermore, catalase, but not superoxide dismutase, inhibited the mitochondrial depolarization as well as apoptosis. So, ESP induce in Eo an early increase in the ROS production, mainly hydrogen peroxide, which precedes mitochondrial injury and leads again to apoptosis. Finally, we demonstrated the participation of hydrogen peroxide in the peritoneal Eo apoptosis in vivo, both during the early stages of experimental fasciolosis in rats and after intraperitoneal ESP treatment.
Asunto(s)
Apoptosis , Eosinófilos/metabolismo , Fasciola hepatica/metabolismo , Peróxido de Hidrógeno/metabolismo , Factores Inmunológicos/farmacología , Mitocondrias/metabolismo , Animales , Eosinófilos/efectos de los fármacos , Eosinófilos/inmunología , Fasciola hepatica/patogenicidad , Fascioliasis/metabolismo , Factores Inmunológicos/metabolismo , Masculino , NADPH Oxidasas/metabolismo , Estrés Oxidativo , Ratas , Ratas Wistar , Especies Reactivas de Oxígeno/metabolismo , SuperóxidosRESUMEN
Glucuronoxylomannan (GXM) is the major component of Cryptococcus capsular polysaccharide, which represents an essential virulence factor for this yeast. Cryptococcus neoformans infections in immunocompetent rats are associated with inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) production by macrophages. This study demonstrates in vitro and in vivo that GXM promotes iNOS expression with NO production in rat macrophages. GXM also induced macrophage apoptosis after 48 h of culture, with this phenomenon being prevented by the iNOS inhibitor, aminoguanidine. The NO-induced macrophage apoptosis triggered by GXM was dependent on interactions with CD18, Fcgamma receptor II and protein kinase C activation, without participation of tyrosine kinases or mitogen-activated protein kinases. Furthermore, this study reveals that GXM down-regulates the macrophage caspase-3 activity, induces a caspase-independent cell death and promotes depolarization of mitochondria membrane potential with increased cytosolic expression of the apoptosis-inducing factor. Taken together, this study describes the pathways and mechanisms involved in the macrophage apoptosis promoted by GXM through NO generation. These findings indicate new mechanisms of immunomodulation for the main capsular polysaccharide of C. neoformans.
Asunto(s)
Caspasa 3/metabolismo , Cryptococcus neoformans/metabolismo , Macrófagos Peritoneales/inmunología , Macrófagos Peritoneales/patología , Óxido Nítrico/genética , Polisacáridos/inmunología , Animales , Apoptosis/efectos de los fármacos , Apoptosis/inmunología , Células Cultivadas , Cryptococcus neoformans/inmunología , Femenino , Regulación Fúngica de la Expresión Génica/inmunología , Macrófagos Peritoneales/efectos de los fármacos , Potencial de la Membrana Mitocondrial , Óxido Nítrico/biosíntesis , Polisacáridos/genética , Polisacáridos/metabolismo , Polisacáridos/farmacología , Ratas , Ratas Wistar , Transducción de Señal/inmunología , Especificidad de la EspecieRESUMEN
Eosinophils (Eo) are known to be important effector cells in the host defense against helminth parasites. Excretory-secretory products (ESP) released by helminths have shown wide immunomodulatory properties, such as the induction of cellular apoptosis. We investigated the ability of ESP from Fasciola hepatica to induce Eo apoptosis. In this work, we observed that ESP induced an early apoptosis of rat peritoneal eosinophils and that this phenomenon was time- and concentration-dependent. Furthermore, we demonstrated that activation of protein tyrosine kinases (TyrK) and caspases were necessary to mediate the Eo apoptosis induced by the ESP, and that carbohydrate components present in these antigens were involved in this effect. We have described for the first time the ability of ESP from F. hepatica to modify the viability of Eo by apoptosis induction. Besides that, we have observed Eo apoptosis in the liver of rats 21 days after F. hepatica infection. The diminution in Eo survival in early infection could be a parasite strategy in order to prevent a host immune response.
Asunto(s)
Antígenos Helmínticos/fisiología , Apoptosis , Caspasas/metabolismo , Eosinófilos/inmunología , Eosinófilos/fisiología , Fasciola hepatica/patogenicidad , Fascioliasis/inmunología , Animales , Células Cultivadas , Ensayo de Inmunoadsorción Enzimática , Eosinófilos/parasitología , Fasciola hepatica/inmunología , Fascioliasis/parasitología , Fascioliasis/fisiopatología , Microscopía Electrónica de Transmisión , Proteínas Tirosina Quinasas/metabolismo , RatasRESUMEN
Different clinical parameters which included cell-mediated immune (CMI) response, were evaluated in a model of disseminated cryptococcosis in rats. The experimental animals were pretreated four days prior to their exposure to Cryptococcus neoformans var. grubii with either heat killed cells of this yeastlike pathogen (HKC) or capsular polysaccharide (CPS) emulsified in complete Freund adjuvant (CFA). Rats treated with HKC-CFA and intraperitoneally infected with C. neoformans var. grubii had significantly better clearance of yeasts from tissues, a lower concentration of the cryptococcal capsular polysaccharide, glucuronoxylomannan (GXM), in serum and tissues, and better histopathological parameters compared to unpretreated infected rats. In contrast, rats treated with CPS-CFA presented an exacerbation of infection with a significantly higher fungal burden in tissues, a higher concentration of GXM in serum, and worse histopathological parameters compared to similar unpretreated infected rats. In addition, HKC-CFA treatment produced a T helper 1 (Th1) profile with improvements in the spleen cell proliferative response, in the level of INFgamma production by CD4 T cells, and in the nitric oxide (NO) production by peritoneal cells. On the other hand, rats treated with CPS-CFA showed an increased level of the immunoregulatory cytokine IL10 production by CD4 T cells, but no modification in the NO production by peritoneal cells.
Asunto(s)
Criptococosis/inmunología , Cryptococcus neoformans/inmunología , Inmunidad Celular , Vacunas de Productos Inactivados/administración & dosificación , Animales , Antígenos Fúngicos/inmunología , Criptococosis/mortalidad , Criptococosis/prevención & control , Cryptococcus neoformans/química , Calor , Polisacáridos/inmunología , Ratas , Bazo/citología , Bazo/inmunología , Linfocitos T/efectos de los fármacos , Linfocitos T/inmunología , Vacunas de Productos Inactivados/inmunologíaRESUMEN
Glucuronoxylomannan (GXM) is the major Cryptococcus neoformans capsular polysaccharide and represents the main virulence factor of this fungus. In in vitro studies we have demonstrated previously that this acidic and high-molecular-weight polysaccharide suppresses lymphoproliferation, modulates cytokine production and promotes apoptosis in spleen mononuclear (Spm) cells from rats. In this study we demonstrate that these phenomena also occur in vivo after the intracardiac inoculation of GXM into normal Wistar rats. The results of this study show suppression of the proliferative response Spm cells to concanavalin A (Con A) or heat-killed C. neoformans (HKCn) in the first 2 weeks after polysaccharide administration. In addition, increased levels of interleukin (IL)-10 were produced by Con A-stimulated Spm cells, coinciding with immunohistochemical GXM detection in the white pulp of spleen. In particular, high production of IL-10 with diminution of IL-2, interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha synthesis were detected 14 days after GXM administration. In situ cell death detection by TdT-mediated biotin-dUTP nick-end labelling (TUNEL) reaction in sections of spleen, lung and liver demonstrates apoptosis in tissues with deposits of GXM. These data demonstrate the in vivo ability of GXM to modify cytokine synthesis by Spm cells and to promote host cell apoptosis.
Asunto(s)
Apoptosis/efectos de los fármacos , Cryptococcus neoformans/inmunología , Tolerancia Inmunológica/efectos de los fármacos , Interleucina-10/biosíntesis , Polisacáridos/inmunología , Animales , Apoptosis/inmunología , División Celular/efectos de los fármacos , Células Cultivadas , Citocinas/biosíntesis , Femenino , Hígado/metabolismo , Pulmón/metabolismo , Polisacáridos/sangre , Polisacáridos/farmacocinética , Ratas , Ratas Wistar , Bazo/inmunología , Bazo/metabolismoRESUMEN
An intense myocarditis is frequently found in the acute phase of Trypanosoma cruzi infection. Despite the cardiac damage, infected individuals may remain asymptomatic for decades. Thus T. cruzi may directly prevent cardiomyocyte death to keep heart destruction in check. Recently, it has been shown that Schwann cell invasion by T. cruzi, their prime target in the peripheral nervous system, suppressed host cell apoptosis caused by growth factor deprivation. Likewise, the trans-sialidase of T. cruzi reproduced this antiapoptotic activity of the parasite. In this study, we have investigated the effect of cruzipain, another important T. cruzi antigen, on survival and cell death of neonatal BALB/c mouse cardiomyocyte cultures. We have found that cruzipain, as well as T. cruzi infection, promoted survival of cardiomyocytes cultured under serum deprivation. The antiapoptotic effect was mediated by Bcl-2 expression but not by Bcl-xL expression. Because arginase activity is involved in cell differentiation and wound healing in most cell types and it favors parasite growth within the cell, we have further investigated the effect of cruzipain on the regulation of l-arginine metabolic pathways. Our results have revealed that cruzipain enhanced arginase activity and the expression of arginase-2 isoform but failed to induce nitric oxide synthase activity. In addition, the inhibition of arginase activity by NG-hydroxy-l-arginine, abrogated the antiapoptotic action of cruzipain. The results demonstrate that cruzipain may act as a survival factor for cardiomyocytes because it rescued them from apoptosis and stimulated arginase-2.
Asunto(s)
Antígenos de Protozoos/farmacología , Arginasa/metabolismo , Cardiotónicos/farmacología , Cisteína Endopeptidasas/farmacología , Miocitos Cardíacos/efectos de los fármacos , Miocitos Cardíacos/fisiología , Trypanosoma cruzi/inmunología , Animales , Animales Recién Nacidos , Arginina/metabolismo , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Medio de Cultivo Libre de Suero , Ratones , Ratones Endogámicos BALB C , Miocitos Cardíacos/enzimología , Óxido Nítrico Sintasa/metabolismo , Proteínas ProtozoariasRESUMEN
Fasciola hepatica somatic antigen, its partially purified fractions and excretion-secretion products were investigated as to serological, electrophoretic and biological properties. In a Sephadex G-100 column (SG-100), Fasciola hepatica total antigen (FhTA) gave 5 fractions, and SDS-PAGE analysis showed they were glycoproteins ranging from 14 to 94 kDa molecular weight (MW). When these fractions were analyzed by enzyme-linked immunotransfer blot (EITB) and immunodiffusion in gel (ID) with serum from immunized rats with FhTA, the presence of different antigenic components was revealed. In the SDS-PAGE of excretor-secretor antigen (ESA), it was possible to observe peptides from 12 to 22 kDa, which were also present in FhTA. When the FhTA, its fractions and the ESA were analyzed by EITB with the immune rat serum (IRS), it was observed that only some fractions of the SG-100 shared antigens with the FhTA and ESA. Moreover, DTH and ITH responses were studied in FhTA immunized rats challenged with these different antigen components, revealing that the protein/carbohydrate ratio is important for inducing DTH response. The ESA was the most active component in the DTH and ITH response
Asunto(s)
Animales , Antígenos Helmínticos/análisis , Fasciola hepatica/inmunología , Antígenos Helmínticos/inmunología , Antígenos Helmínticos/aislamiento & purificación , Cromatografía en Gel , Electroforesis en Gel de Poliacrilamida , Ensayo de Inmunoadsorción Enzimática , Hipersensibilidad Tardía/inmunología , Hipersensibilidad Inmediata/inmunología , Immunoblotting , InmunodifusiónRESUMEN
The objective of the present work was to carry out a survey of soil samples taken from different areas of a hospital of infectious disease located in the city of Córdoba, where three AIDS patients were hospitalized during different periods in the same ward. The three of them returned with meningeal cryptococcosis between three or five months after having been discharged. Cryptococcus neoformans was isolated in 8/10 samples collected outside the hospital, near the pigeon house. The samples collected from the AIDS patients ward and its surroundings were negative. These findings suggest that the patients may have been infected by the fungus during their first stay in hospital