RESUMEN

Entamoeba histolytica is the causative agent of amoebiasis, and Entamoeba dispar is its noninvasive morphological twin. Entamoeba invadens is a reptilian parasite. In the present study, Western blot, phosphatase activity, immunofluorescence, and bioinformatic analyses were used to identify PP2C phosphatases of E. histolytica, E. dispar, and E. invadens. PP2C was identified in trophozoites of all Entamoeba species and cysts of E. invadens. Immunoblotting using a Leishmania mexicana anti-PP2C antibody recognized a 45.2 kDa PP2C in all species. In E. histolytica and E. invadens, a high molecular weight element PP2C at 75 kDa was recognized, mainly in cysts of E. invadens. Immunofluorescence demonstrated the presence of PP2C in membrane and vesicular structures in the cytosol of all species analyzed. The ~75 kDa PP2C of Entamoeba spp. shows the conserved domain characteristic of phosphatase enzymes (according to in silico analysis). Possible PP2C participation in the encystation process was discussed.

Asunto(s)

Entamoeba/enzimología , Proteína Fosfatasa 2C/metabolismo , Proteínas Protozoarias/metabolismo , Trofozoítos/enzimología , Secuencia de Aminoácidos , Animales , Entamoeba/aislamiento & purificación , Entamebiasis/parasitología , Entamebiasis/patología , Humanos , Filogenia , Proteína Fosfatasa 2C/química , Proteína Fosfatasa 2C/genética , Proteínas Protozoarias/química , Proteínas Protozoarias/genética , Homología de Secuencia de Aminoácido , Trofozoítos/aislamiento & purificación

RESUMEN

BACKGROUND: The parasite Entamoeba histolytica is the causal agent of amoebiasis, a worldwide emerging disease. Amebic brain abscess is a form of invasive amebiasis that is both rare and frequently lethal. This condition always begins with the infection of the colon by E. histolytica trophozoites, which subsequently travel through the bloodstream to extraintestinal tissues. CASE PRESENTATION: We report a case of a 71-year-old female who reported an altered state of consciousness, disorientation, sleepiness and memory loss. She had no history of hepatic or intestinal amoebiasis. A preliminary diagnosis of colloidal vesicular phase neurocysticercosis was made based on nuclear magnetic resonance imaging (NMRI). A postsurgery immunofluorescence study was positive for the 140 kDa fibronectin receptor of E. histolytica, although a serum analysis by ELISA was negative for IgG antibodies against this parasite. A specific E. histolytica 128 bp rRNA gene was identified by PCR in biopsy tissue. The final diagnosis was cerebral amoebiasis. The patient underwent neurosurgery to eliminate amoebic abscesses and was then given a regimen of metronidazole, ceftriaxone and dexamethasone for 4 weeks after the neurosurgery. However, a rapid decline in her condition led to death. CONCLUSIONS: The present case of an individual with a rare form of cerebral amoebiasis highlights the importance of performing immunofluorescence, NMRI and PCR if a patient has brain abscess and a poorly defined diagnosis. Moreover, the administration of corticosteroids to such patients can often lead to a rapid decline in their condition.

Asunto(s)

Absceso Encefálico/diagnóstico , Absceso Encefálico/parasitología , Infecciones Parasitarias del Sistema Nervioso Central/diagnóstico , Entamebiasis/diagnóstico , Anciano , Animales , Absceso Encefálico/tratamiento farmacológico , Absceso Encefálico/cirugía , Ceftriaxona/administración & dosificación , Infecciones Parasitarias del Sistema Nervioso Central/tratamiento farmacológico , Infecciones Parasitarias del Sistema Nervioso Central/patología , Infecciones Parasitarias del Sistema Nervioso Central/cirugía , Terapia Combinada , ADN Protozoario/análisis , Dexametasona/administración & dosificación , Quimioterapia Combinada , Entamoeba histolytica/genética , Entamoeba histolytica/inmunología , Entamoeba histolytica/aislamiento & purificación , Entamebiasis/tratamiento farmacológico , Entamebiasis/patología , Entamebiasis/cirugía , Resultado Fatal , Femenino , Humanos , Metronidazol/administración & dosificación , Procedimientos Neuroquirúrgicos , Pruebas Serológicas

RESUMEN

Entamoeba histolytica is a protozoan parasite responsible for amoebiasis, a disease with a high prevalence in developing countries. Establishing an amoebic infection involves interplay between pathogenic factors for invasion and tissue damage, and immune responses for protecting the host. Here, we review the pathogenicity of E. histolytica and summarize the latest knowledge on immune response and immune evasion mechanisms during amoebiasis.

Asunto(s)

Entamoeba histolytica/inmunología , Entamebiasis/inmunología , Intestino Delgado/inmunología , Neutrófilos/inmunología , Animales , Entamebiasis/parasitología , Entamebiasis/patología , Humanos , Inmunidad , Intestino Delgado/metabolismo , Intestino Delgado/parasitología , Neutrófilos/patología

Asunto(s)

Infecciones Oportunistas Relacionadas con el SIDA/etiología , Aspergilosis/microbiología , Coccidioidomicosis/microbiología , Entamebiasis/parasitología , Infecciones por VIH/complicaciones , Aspergilosis/etiología , Aspergilosis/patología , Aspergillus/aislamiento & purificación , Coccidioides/aislamiento & purificación , Coccidioidomicosis/etiología , Coccidioidomicosis/patología , Entamoeba histolytica/aislamiento & purificación , Entamebiasis/etiología , Entamebiasis/patología , Resultado Fatal , Humanos , Masculino , Persona de Mediana Edad

RESUMEN

Epidemiological studies suggest frequent association of enteropathogenic bacteria with Entamoeba histolytica during symptomatic infection. In this study, we sought to determine if the interaction with enteropathogenic (EPEC) or nonpathogenic Escherichia coli (strain DH5α) could modify the virulence of E. histolytica to cause disease in animal models of amebiasis. In vitro studies showed a 2-fold increase in CaCo2 monolayer destruction when E. histolytica interacted with EPEC but not with E. coli DH5α for 2.5 h. This was associated with increased E. histolytica proteolytic activity as revealed by zymogram analysis and degradation of the E. histolytica CP-A1/5 (EhCP-A1/5) peptide substrate Z-Arg-Arg-pNC and EhCP4 substrate Z-Val-Val-Arg-AMC. Additionally, E. histolytica-EPEC interaction increased EhCP-A1, -A2, -A4, and -A5, Hgl, Apa, and Cox-1 mRNA expression. Despite the marked upregulation of E. histolytica virulence factors, nonsignificant macroscopic differences in amebic liver abscess development were observed at early stages in hamsters inoculated with either E. histolytica-EPEC or E. histolytica-E. coli DH5α. Histopathology of livers of E. histolytica-EPEC-inoculated animals revealed foci of acute inflammation 3 h postinoculation that progressively increased, producing large inflammatory reactions, ischemia, and necrosis with high expression of il-1ß, ifn-γ, and tnf-α proinflammatory cytokine genes compared with that in livers of E. histolytica-E. coli DH5α-inoculated animals. In closed colonic loops from mice, intense inflammation was observed with E. histolytica-EPEC manifested by downregulation of Math1 mRNA with a corresponding increase in the expression of Muc2 mucin and proinflammatory cytokine genes il-6, il-12, and mcp-1 These results demonstrate that E. histolytica/EPEC interaction enhanced the expression and production of key molecules associated with E. histolytica virulence, critical in pathogenesis and progression of disease.

Asunto(s)

Entamoeba histolytica/patogenicidad , Entamebiasis/patología , Escherichia coli Enteropatógena/fisiología , Interacciones Microbiota-Huesped/fisiología , Animales , Células CACO-2 , Línea Celular , Cricetinae , Proteasas de Cisteína/metabolismo , Citocinas/metabolismo , Entamoeba histolytica/microbiología , Células HT29 , Humanos , Inflamación , Mesocricetus , Ratones , Ratones Endogámicos C57BL , Mucina 2/metabolismo , Factores de Virulencia/biosíntesis

RESUMEN

Amoebiasis is a parasitic disease that causes thousands of deaths every year, its adverse effects and resistance to conventional treatments have led to the search of new treatment options, as well as the development of novel screening methods. In this work, we implemented a 3D model of intestine and liver slices from hamsters that were infected ex vivo with virulent E. histolytica trophozoites. Results show preserved histology in both uninfected tissues as well as ulcerations, destruction of the epithelial cells, and inflammatory reaction in intestine slices and formation of micro abscesses, and the presence of amoebae in the sinusoidal spaces and in the interior of central veins in liver slices. The three chemically synthetized compounds T-001, T-011, and T-016, which act as amoebicides in vitro, were active in both infected tissues, as they decreased the number of trophozoites, and provoked death by disintegration of the amoeba, similar to metronidazole. However, compound T-011 induced signs of cytotoxicity to liver slices. Our results suggest that ex vivo cultures of precision-cut intestinal and liver slices represent a reliable 3D approach to evaluate novel amoebicidal compounds, and to simultaneously detect their toxicity, while reducing the number of experimental animals commonly required by other model systems.

Asunto(s)

Amebicidas/farmacología , Evaluación Preclínica de Medicamentos , Entamoeba histolytica/efectos de los fármacos , Hígado/parasitología , Modelos Moleculares , Animales , Muerte Celular/efectos de los fármacos , Cricetinae , Entamebiasis/parasitología , Entamebiasis/patología , Intestinos/parasitología , Masculino

RESUMEN

During intestinal invasion, Entamoeba histolytica opens tight junctions (TJs) reflected by transepithelial electrical resistance (TEER) dropping. To explore the molecular mechanisms underlying this, we studied in vitro and in vivo the damage produced by the recombinant E. histolytica cysteine protease (rEhCP112) on TJ functions and proteins. rEhCP112 reduced TEER in Caco-2 cells in a dose- and time-dependent manner; and EhCP112-overexpressing trophozoites provoked major epithelial injury compared to control trophozoites. rEhCP112 penetrated through the intercellular space, and consequently the ion flux increased and the TJs fence function was disturbed. However, macromolecular flux was not altered. Functional in vitro assays revealed specific association of rEhCP112 with claudin-1 and claudin-2, that are both involved in regulating ion flux and fence function. Of note, rEhCP112 did not interact with occludin that is responsible for regulating macromolecular flux. Moreover, rEhCP112 degraded and delocalized claudin-1, thus affecting interepithelial adhesion. Concomitantly, expression of the leaky claudin-2 at TJ, first increased and then it was degraded. In vivo, rEhCP112 increased intestinal epithelial permeability in the mouse colon, likely due to apical erosion and claudin-1 and claudin-2 degradation. In conclusion, we provide evidence that EhCP112 causes epithelial dysfunction by specifically altering claudins at TJ. Thus, EhCP112 could be a potential target for therapeutic approaches against amoebiasis.

Asunto(s)

Proteínas Bacterianas/farmacología , Claudina-1/efectos de los fármacos , Claudina-2/efectos de los fármacos , Cisteína Endopeptidasas/farmacología , Entamoeba histolytica/metabolismo , Células Epiteliales/efectos de los fármacos , Intestinos/efectos de los fármacos , Uniones Estrechas/efectos de los fármacos , Animales , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Células CACO-2 , Supervivencia Celular/efectos de los fármacos , Claudina-1/metabolismo , Claudina-2/metabolismo , Claudina-4/efectos de los fármacos , Colon/efectos de los fármacos , Colon/parasitología , Cisteína Endopeptidasas/genética , Cisteína Endopeptidasas/metabolismo , Modelos Animales de Enfermedad , Perros , Entamoeba histolytica/genética , Entamoeba histolytica/patogenicidad , Entamebiasis/patología , Regulación de la Expresión Génica , Humanos , Células de Riñón Canino Madin Darby , Masculino , Ratones , Ratones Endogámicos C57BL , Ocludina/efectos de los fármacos , Permeabilidad , Proteínas Recombinantes/farmacología , Uniones Estrechas/metabolismo , Trofozoítos/genética , Trofozoítos/metabolismo , Proteína de la Zonula Occludens-1/efectos de los fármacos

RESUMEN

Entamoeba histolytica trophozoites adhere to epithelium at the cell-cell contact and perturb tight junctions disturbing the transepithelial electrical resistance. Behind tight junctions are the adherens junctions (AJs) that reinforce them and the desmosomes (DSMs) that maintain the epithelium integrity. The damage produced to AJs and DMSs by this parasite is unknown. Here, we studied the effect of the trophozoites, the EhCPADH complex, and the EhCP112 recombinant enzyme (rEhCP112) on AJ and DSM proteins. We found that trophozoites degraded ß-cat, E-cad, Dsp l/ll, and Dsg-2 with the participation of EhCPADH and EhCP112. After contact of epithelial cells with trophozoites, immunofluorescence and transmission electron microscopy assays revealed EhCPADH and rEhCP112 at the intercellular space where they colocalised with ß-cat, E-cad, Dsp l/ll, and Dsg-2. Moreover, our results suggested that rEhCP112 could be internalised by caveolae and clathrin-coated vesicles. Immunoprecipitation assays showed the interaction of EhCPADH with ß-cat and Dsp l/ll. Besides, in vivo assays demonstrated that rEhCP112 concentrates at the cellular borders of the mouse intestine degrading E-cad and Dsp I/II. Our research gives the first clues on the trophozoite attack to AJs and DSMs and point out the role of the EhCPADH and EhCP112 in the multifactorial event of trophozoites virulence.

Asunto(s)

Uniones Adherentes/metabolismo , Cisteína Endopeptidasas/metabolismo , Entamoeba histolytica/enzimología , Entamoeba histolytica/metabolismo , Entamebiasis/patología , Uniones Estrechas/metabolismo , Animales , Anticuerpos Monoclonales/inmunología , Anticuerpos Antiprotozoarios/inmunología , Células CACO-2 , Cadherinas/metabolismo , Línea Celular , Desmosomas/metabolismo , Perros , Entamoeba histolytica/inmunología , Entamebiasis/parasitología , Células Epiteliales/metabolismo , Humanos , Mucosa Intestinal/parasitología , Células de Riñón Canino Madin Darby , Masculino , Ratones , Ratones Endogámicos C57BL , beta Catenina/metabolismo

RESUMEN

Entamoeba histolytica is the causative agent of amebiasis in humans and is responsible for 100,000 deaths annually, making it the third leading cause of death due to a protozoan parasite. Pathogenesis appears to result from the potent cytotoxic activity of the parasite, which kills host cells within minutes. Although the mechanism is unknown, it is well established to be contact-dependent. The life cycle of the parasite alternates with two forms: the resistant cyst and the invasive trophozoite. The adhesive interactions between the parasite and surface glycoconjugates of host cells, as well as those lining the epithelia, are determinants for invasion of human tissues, for its cytotoxic activity, and finally for the outcome of the disease. In this review we present an overview of the information available on the amebic lectins and adhesins that are responsible of those adhesive interactions and we also refer to their effect on the host immune response. Finally, we present some concluding remarks and perspectives in the field.

Asunto(s)

Moléculas de Adhesión Celular/metabolismo , Entamoeba histolytica/metabolismo , Entamebiasis/metabolismo , Lectinas/metabolismo , Proteínas Protozoarias/metabolismo , Trofozoítos/metabolismo , Animales , Entamoeba histolytica/patogenicidad , Entamebiasis/patología , Humanos

RESUMEN

Entamoeba gingivalis is considered an oral commensal but demonstrates a pathogenic potential associated with periodontal disease in immunocompromised individuals. Therefore, this study evaluated the occurrence, opportunistic conditions, and intraspecific genetic variability of E. gingivalis in HIV(+)/AIDS patients. Entamoeba gingivalis was studied using fresh examination (FE), culture, and PCR from bacterial plaque samples collected from 82 HIV(+)/AIDS patients. Genetic characterization of the lower ribosomal subunit of region 18S (18S-SSU rRNA) was conducted in 9 positive samples using low-stringency single specific primer PCR (LSSP-PCR) and sequencing analysis. Entamoeba gingivalis was detected in 63.4% (52/82) of the samples. No association was detected between the presence of E. gingivalis and the CD4(+) lymphocyte count (≤200 cells/mm(3) (p = 0.912) or viral load (p = 0.429). The LSSP-PCR results helped group E. gingivalis populations into 2 polymorphic groups (68.3% similarity): group I, associated with 63.6% (7/11) of the samples, and group II, associated with 36.4% (4/11) of the samples, which shared 74% and 83.7% similarity and association with C and E isolates from HIV(-) individuals, respectively. Sequencing of 4 samples demonstrated 99% identity with the reference strain ATCC 30927 and also showed 2 divergent clusters, similar to those detected by LSSP-PCR. Opportunistic behavior of E. gingivalis was not detected, which may be related to the use of highly active antiretroviral therapy by all HIV(+)/AIDS patients. The high occurrence of E. gingivalis in these patients can be influenced by multifactorial components not directly related to the CD4(+) lymphocyte counts, such as cholesterol and the oral microbiota host, which could mask the potential opportunistic ability of E. gingivalis. The identification of the 18S SSU-rRNA polymorphism by LSSP-PCR and sequencing analysis provides the first evidence of genetic variability in E. gingivalis isolated from HIV patients.

Asunto(s)

Síndrome de Inmunodeficiencia Adquirida/inmunología , Entamoeba/clasificación , Entamebiasis/inmunología , VIH , Huésped Inmunocomprometido , Filogenia , ARN Ribosómico 18S/clasificación , Síndrome de Inmunodeficiencia Adquirida/tratamiento farmacológico , Síndrome de Inmunodeficiencia Adquirida/patología , Síndrome de Inmunodeficiencia Adquirida/virología , Adulto , Terapia Antirretroviral Altamente Activa , Recuento de Linfocito CD4 , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/patología , Coinfección , Entamoeba/genética , Entamoeba/aislamiento & purificación , Entamebiasis/parasitología , Entamebiasis/patología , Femenino , Variación Genética , Humanos , Masculino , Persona de Mediana Edad , Familia de Multigenes , ARN Ribosómico 18S/genética , Análisis de Secuencia de ADN , Especificidad de la Especie , Carga Viral

RESUMEN

Protein kinases (PKs) of parasitic protozoa are being evaluated as drug targets. A large number of protein kinases within the protein kinome of Entamoeba histolytica strongly suggest that protein phosphorylation is a key component of pathogenesis regulation by this parasite. PI3 K and Src are kinases previously described in this parasite, but their role is poorly understood. Here, the effect of Src-1-inhibitor and PI3 K inhibitor (Wortmannin) on the virulence factors of E. histolytica was evaluated. Results show that both inhibitors affect the actin cytoskeleton and the amoebic movement. Also, the proteolytic activity is diminished by Wortmannin, but not by Src-inhibitor-1; however, the phagocytic capacity is diminished by Wortmannin and Src-1-inhibitor. Finally, we found that the virulence in vivo of E. histolytica is affected by Wortmannin but not by Src-1-inhibitor. This study opens the way for the design of anti-amoebic drugs based on kinase inhibition.

Asunto(s)

Entamoeba histolytica/efectos de los fármacos , Entamoeba histolytica/enzimología , Inhibidores de Proteínas Quinasas/farmacología , Factores de Virulencia/metabolismo , Citoesqueleto de Actina/efectos de los fármacos , Androstadienos/farmacología , Androstadienos/uso terapéutico , Animales , Células Cultivadas , Cricetinae , Entamoeba histolytica/patogenicidad , Entamebiasis/tratamiento farmacológico , Entamebiasis/patología , Humanos , Masculino , Fagocitosis/efectos de los fármacos , Fosfatidilinositol 3-Quinasas/metabolismo , Inhibidores de Proteínas Quinasas/uso terapéutico , Proteolisis/efectos de los fármacos , Wortmanina , Familia-src Quinasas/metabolismo

RESUMEN

BACKGROUND: Melatonin has immunomodulatory effects but very little is known about its influence in protozoan infections, such as Entamoeba histolytica, which causes amoebiasis, a disease with significant morbidity and mortality. In this study, we evaluated the effects of exogenous melatonin interference in experimental amoebiasis and on interactions between human blood cells and E. histolytica trophozoites. METHODS: The effect of melatonin was investigated in models of experimental amoebiasis in hamsters and rats by evaluating the area of necrosis induced by E. histolytica. The activity of melatonin on the interactions between leukocytes and amoebae was determined by examining leukophagocytosis. For in vitro tests, polymorphonuclear and mononuclear human blood leucocytes were incubated with E. histolytica trophozoites. RESULTS: The areas of amoebic necrosis were significantly reduced in animals treated with melatonin. Melatonin treatment increased leukophagocytosis but was associated with a greater number of dead amoebae. CONCLUSIONS: These results suggest that melatonin may play a beneficial role in the control of amoebic lesions, raising the possibility that this drug may be used as an adjuvant in anti-amoebic therapy.

Asunto(s)

Entamebiasis/patología , Entamebiasis/parasitología , Factores Inmunológicos/administración & dosificación , Melatonina/administración & dosificación , Adolescente , Adulto , Animales , Células Cultivadas , Cricetinae , Modelos Animales de Enfermedad , Entamoeba histolytica , Histocitoquímica , Humanos , Leucocitos/inmunología , Leucocitos/parasitología , Hígado/patología , Masculino , Microscopía , Fagocitosis/efectos de los fármacos , Ratas , Ratas Wistar , Enfermedades de los Roedores/parasitología , Enfermedades de los Roedores/patología , Adulto Joven

RESUMEN

The sequence of hepatic necrotic-inflammatory events produced by Entamoeba dispar are originally described in this work. For the first time were described in details the experimental lesions produced by E. dispar, as well as the distribution of the trophozoites detected by the immunohistochemistry. Animals experimentally infected with E. dispar presented necrosis, thrombosis and chronic granulomatous inflammation. Immunoreactive products derived from trofozoites were observed close or associated with trophozoites, epithelioid cells, leucocytes and hepatocytes. Few are the articles on the literature about virulence of E. dispar, which is approximately 9 times more frequent than to E. histolytica. Variation in the virulence is, therefore expected and signalizing the need of the continuity of studies with E. dispar strains from different places in the world. Taking into account that E. dispar is a closely related species to E. histolytica, these studies could determine new elements involved with E. histolytica pathogenesis, helping us to understand better the disease.

Asunto(s)

Entamoeba/fisiología , Entamebiasis/complicaciones , Parasitosis Hepáticas/patología , Hígado/patología , Animales , Cricetinae , Entamebiasis/inmunología , Entamebiasis/patología , Enfermedad Granulomatosa Crónica/patología , Inmunohistoquímica , Inflamación/patología , Necrosis/etiología , Necrosis/patología , Ratas , Trombosis/etiología , Trombosis/patología

RESUMEN

Cysteine proteinase (CP) activity and CP5 mRNA levels were analyzed in eleven samples of Entamoeba histolytica isolated from patients presenting different clinical profiles. The virulence degree of the isolates, determined in hamster liver, correlated well with the clinical form of the patient and culture conditions. CP5 mRNA levels were also determined in sample freshly picked up directly from liver amoebic abscess. Differences were not observed in the levels of CP5 mRNA and CP specific activity among the cultured samples. However, different levels of CP5 mRNA were observed in trophozoite freshly isolated from hepatic amoebic lesions. These results reinforce the importance of CP5 for the virulence of amoebae and the need for studies with the parasite present in lesions to validate mechanisms involved in pathogenesis of amoebiasis.

Asunto(s)

Cisteína Endopeptidasas/metabolismo , Entamoeba histolytica/enzimología , Entamoeba histolytica/patogenicidad , Entamebiasis/parasitología , Absceso Hepático Amebiano/parasitología , Animales , Cricetinae , Cisteína Endopeptidasas/genética , Entamoeba histolytica/genética , Entamebiasis/patología , Regulación Enzimológica de la Expresión Génica , Humanos , Hígado/parasitología , Hígado/patología , Absceso Hepático Amebiano/patología , Mesocricetus , Reacción en Cadena de la Polimerasa , ARN Mensajero/análisis , Virulencia

RESUMEN

The human large intestine can harbor two morphologically similar amoebae; the invasive Entamoeba histolytica and the non-invasive Entamoeba dispar. Whereas E. histolytica can produce intestinal and extra-intestinal lesions, E. dispar is present in non-symptomatic carriers. Although biochemical, genetic and proteomic studies have identified clear differences between these Entamoebae, it has become clear that several molecules, once assumed to be involved in tissue destruction, exist in both the virulent and the avirulent species. As surface molecules may play a role in invasion and could therefore determine which amoebae are invasive, we analyzed the glycoconjugate composition of E. histolytica and E. dispar using lectins. There was a significant difference between E. histolytica and E. dispar in the expression of glycoconjugates containing d-mannose and N-acetyl-alpha-D-galactosamine residues, but not between virulent and avirulent strains of E. histolytica. N-glycoconjugates with terminal alpha (1-3)-linked mannose residues participate in the adhesion and subsequent cytotoxicity of E. histolytica to cultured hamster hepatocytes. One of them probably is the Gal/GalNAc lectin.

Asunto(s)

Entamoeba histolytica/metabolismo , Entamoeba/metabolismo , Glicoconjugados/metabolismo , Acetilgalactosamina/análisis , Animales , Adhesión Celular , Células Cultivadas , Cricetinae , Entamoeba/clasificación , Entamoeba/crecimiento & desarrollo , Entamoeba/patogenicidad , Entamoeba histolytica/crecimiento & desarrollo , Entamoeba histolytica/patogenicidad , Entamebiasis/parasitología , Entamebiasis/patología , Glicoconjugados/química , Hepatocitos/parasitología , Hepatocitos/patología , Absceso Hepático Amebiano/parasitología , Absceso Hepático Amebiano/patología , Manosa/análisis , Virulencia

RESUMEN

The purpose of the present paper was to analyse the association between sequences of Entamoeba histolytica and their relationship with the development of hepatic abscesses in hamsters, using a complementary DNA library for E. histolytica. From the sequences obtained, we designed oligonucleotides for amplification by PCR. Trophozoites were isolated from faeces of 11 patients in whom cysts from E. histolytica were identified, and these trophozoites were then subjected to monoaxenic culture. Then 1 x 10(5) trophozoites were inoculated into hamster liver, with three hamsters used for every culture. Sequences were obtained for ubiquitin, lectin surface precursor, replication factor MCM3 and surface antigen. The associations between sequences and hepatic abscesses were: 11/11 for ubiquitin, 9/11 for lectin precursor, 4/11 for replication factor and 1/11 for surface antigen. These results suggest that ubiquitin could be an important protein involved in the mechanism of E. histolytica invasion.

Asunto(s)

Entamoeba histolytica/patogenicidad , Entamebiasis/patología , Absceso Hepático Amebiano/patología , Ubiquitina/genética , Animales , Secuencia de Bases , Cricetinae , Entamoeba histolytica/genética , Entamoeba histolytica/crecimiento & desarrollo , Entamoeba histolytica/aislamiento & purificación , Entamebiasis/parasitología , Biblioteca de Genes , Humanos , Absceso Hepático Amebiano/parasitología , Datos de Secuencia Molecular , Proteínas Protozoarias/química , Proteínas Protozoarias/genética , Ubiquitina/química

RESUMEN

Studies in mice have not rendered conclusive data on cell and humoral factors to support the resistance of this rodent to Entamoeba histolytica infection. In Balb/c and C3H/HeJ mice inoculated with live or fixed trophozoites, we studied the evolution of the hepatic lesion, the kinetics of inflammatory cells, and the participation of some humoral factors in the development of the hepatic amoebic lesion. From the first hour, amoebae were surrounded by neutrophils containing inducible nitric oxide synthase (iNOS); macrophages also expressing iNOS appeared lately, whereas NK cells were not part of the inflammatory infiltrates. On the fourth day, neutrophils, macrophages, T and B lymphocytes, plasma cells, and some NK cells limited the lesions and anti-amoeba antibodies appeared when most parasites had been eliminated. Therefore, the resistance of the mice to E. histolytica probably lies in non-specific immune responses, among which the activation of neutrophils and the production of nitric oxide (NO) may be important amoebicide factors.

Asunto(s)

Entamoeba histolytica/inmunología , Entamebiasis/inmunología , Neutrófilos/inmunología , Óxido Nítrico/metabolismo , Animales , Entamoeba histolytica/patogenicidad , Entamebiasis/parasitología , Entamebiasis/patología , Inmunoglobulina G/sangre , Inmunoglobulina M/sangre , Inmunohistoquímica , Hígado/parasitología , Hígado/patología , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C3H , Necrosis , Neutrófilos/enzimología , Óxido Nítrico Sintasa/metabolismo , Óxido Nítrico Sintasa de Tipo II

Asunto(s)

Dientamoeba/citología , Dientamoeba/parasitología , Dientamebiasis/diagnóstico , Dientamebiasis/parasitología , Dientamebiasis/patología , Disentería Amebiana/diagnóstico , Disentería Amebiana/parasitología , Disentería Amebiana/patología , Entamebiasis/diagnóstico , Entamebiasis/parasitología , Entamebiasis/patología , Coloración y Etiquetado

Asunto(s)

Entamoeba histolytica/patogenicidad , Entamebiasis/patología , Animales , Colon/patología , Colon/fisiopatología , Modelos Animales de Enfermedad , Electrofisiología , Entamebiasis/etiología , Entamebiasis/fisiopatología , Técnicas In Vitro , Mucosa Intestinal/patología , Mucosa Intestinal/fisiopatología , Microscopía Electrónica , Conejos , Factores de Tiempo

Asunto(s)

Colon/patología , Colon/fisiopatología , Entamoeba histolytica/patogenicidad , Entamebiasis/patología , Entamebiasis/fisiopatología , Animales , Modelos Animales de Enfermedad , Electrofisiología , Entamoeba histolytica/crecimiento & desarrollo , Entamebiasis/etiología , Hipoxia/patología , Hipoxia/fisiopatología , Técnicas In Vitro , Conejos