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PubMedDate not supplied

The house mouse: a potential intermediate host for Echinococcus multilocularis in France.

An adult house mouse infected with an alveolar hydatid of Echinococcus multilocularis was trapped in the cellar of an inhabited house in a small village in Auvergne (France) where 3 human cases of alveolar hydatid disease had been diagnosed. The rodent harboured a young hepatic larval cyst. This indicated the presence of infective eggs of the parasite inside the house and outbuildings, an important observation concerning the circulation of the parasite in a domestic environment.

Animals↗
PubMedDate not supplied

Detection of antibodies against Echinococcus granulosus major antigens and their subunits by immunoblotting.

An immunoblot assay was tested to evaluate its ability to diagnose human hydatidosis and to analyse the reactivity of hydatid patients' sera with the subunits of the 2 major Echinococcus granulosus antigens (5 and B). In all, 308 sera were examined: 166 sera from patients with clinically diagnosed hydatidosis, 100 sera from healthy control subjects, and 42 sera from patients with diseases other than hydatidosis. The sensitivity of the method was 90%, as compared to 78% with the immunoelectrophoresis/double diffusion test for antigen 5. No reactivity was found with 15 sera from patients with schistosomiasis, 7 sera from patients with trichinellosis, or 20 sera from patients with non-parasitic diseases. Analysis of serum reactivities showed the presence in all positive sera of antibodies directed against the 39 kDa molecule of the antigen 5 complex. A lower reactivity (55% of all hydatid sera) was observed with the subunits of the antigen B complex.

Animals↗
PubMedDate not supplied

Serological evaluation of the 12 kDa subunit of antigen B in Echinococcus granulosus cyst fluid by immunoblot analysis.

This study evaluated the 12 kDa (smallest) subunit of Echinococcus granulosus antigen B as a diagnostic molecule. Using immunoblotting, 90.9% of cystic hydatid patients, 40% of alveolar hydatid patients and 5.5% of cysticercosis patients showed sero-reactivity to this subunit. Human antibody response to the 12 kDa molecule appeared independent of factors such as parasite strain or host population responsiveness. The majority of infection sera, and some normal human controls, also recognized the 38 kDa subunit of antigen 5.

Animals↗
PubMed1986

Humoral immunity in the prepatent primary infection of dogs with Echinococcus granulosus.

Twenty-one parasite-naive dogs were infected with 60,000 protoscolices of Echinococcus granulosus. Transformation of peripheral lymphocytes was investigated before and 29 days after the infection, immunoglobulin concentration and anti-hydatid fluid protein (HFP) titers in serum and feces before and at 35 days of infection, skin reactivity to HFP at 36 days, and characteristics of the parasites at 40 days. The infection caused a significant depression of the spontaneous, lipopolysaccharide-stimulated, and purified protein derivative-stimulated blastogenesis. Responses to phytohemagglutinin were unchanged and reactivity to concanavalin A was enhanced with the infection. Only the concentrations of IgG and IgA in the serum and IgA in the feces increased significantly after infection. Fifteen (71%) dogs produced significant serum titers of anti-HFP hemagglutinins but copro-antibodies were detectable in only 3 dogs at minimum titers. Titers were abolished by treatment with 2-mercaptoethanol. The serum of 11 (52%) dogs transferred passive cutaneous anaphylaxis to guinea pigs but none transferred skin reactivity to pups or rabbits. Five and 1 (but not 0.2) micrograms of HFP caused skin reactivity in 4 parasite-naive dogs. Nineteen (90.5%) infected dogs reacted significantly to skin inoculation of 0.2 microgram of HFP at 0.5 hours and 13 (62%) at 6 hours. The 7 dogs with the highest anti-HFP serum titers or the greatest skin reactivity at 6 hours had significantly less mature or fewer tissue parasites, respectively, than the 7 dogs with the smallest responses. Since there was evidence that the specific immunity was still developing at the time of the study, these results indicate that immunological diagnosis of, and artificial immunization against, canine echinococcosis are feasible.

Animals↗
PubMed1986

Cell-mediated immunity in the prepatent primary infection of dogs with Echinococcus granulosus.

Cell-mediated immunity was studied in 21 parasite-naive dogs by transformation of peripheral lymphocytes with phytohemagglutinin (PHA), concanavalin A (Con A), or hydatid fluid protein (HFP) at 29 days of a primary infection with Echinococcus granulosus, and by delayed cutaneous hypersensitivity to HFP at 36 days of the infection. Infection depressed significantly the ability of unstimulated cells to proliferate but enhanced the response to Con A. The lymphocytes of four dogs reacted to HFP significantly above the average, and one dog exhibited cutaneous reactivity to 0.2 micrograms of HFP. Five or 1 but not 0.2 micrograms of HFP produced non-specific skin reactions in parasite-naive dogs. The 7 dogs with the highest reactivity to PHA or Con A had significantly fewer parasites than the 7 less reactive dogs. The differences in other parasite characteristics were not significant in the 7 dogs with the greatest or smallest reactivities. Correlation tests showed an inverse correlation of PHA reactivity with establishment and maturation of parasites, of Con A reactivity with growth and maturation, and of HFP with maturation.

Animals↗
PubMed1984

Membrane permeability of secondary hydatid cysts of Echinococcus granulosus. Determination of the water diffusional and osmotic permeability coefficients through a syncytial membrane.

Diffusional (Pw) and osmotic (Pf) water permeability coefficients were determined for the syncytial epithelium of larval Echinococcus granulosus. Pw was calculated from simultaneous influx measurements of tritiated water and n-[14C]butanol through the hydatid cyst wall. The total diffusional water permeability coefficient, P'w, was found to be 2.2 X 10(-4) cm s-1; which is similar to that previously reported by Rotunno et al. (1974, J. Parasitol. 60, 13-620). Nevertheless, when P'f is corrected for the unstirred water layer effects, a Pw value of 6.2 X 10(-4) cm s-1 is obtained. Thus, the unstirred water layer effects have a very important contribution to P'w. Total steady state osmotic permeability coefficient, P'f, was bound to be about 15 X 10(-4) cm s-1 and it is scarcely affected by those mechanisms that tend to distort the evaluation of Pf. The experimentally determined osmotic coefficient differs from the corrected Pf by only 6%. The Pf/Pw ratio was found to be 2.4. The present study clearly confirms that syncytial membranes can be highly permeable to water, in spite of the fact that they lack tight junctions. Thus, water permeability through epithelial syncytium must be exclusively controlled by the permeability of the apical and/or basocellular membranes.

Animals↗
PubMed1985

Identification of the Echinococcus (hydatid disease) organisms using cloned DNA markers.

Cloned DNA fragments of the ribosomal RNA gene of Schistosoma mansoni hybridise strongly to Echinococcus DNA following restriction endonuclease and Southern transfer analysis. Individuals within a strain of E. granulosus exhibit identical patterns of hybridisation. However, the hybridisation patterns show significant differences between E. granulosus and E. multilocularis, and between the horse and sheep strains of E. granulosus. This technique represents a powerful, additional method for the identification and characterisation of new isolates of E. granulosus and E. multilocularis.

Animals↗
PubMed1986

Purification and partial characterization of the major antigen of Echinococcus granulosus (antigen 5) with monoclonal antibodies.

A monoclonal antibody specific for antigen 5 of Echinococcus granulosus was isolated and partially characterized. Purification of antigen 5 was accomplished by affinity chromatography using an immunoabsorbent prepared with this monoclonal antibody. Pure antigen 5 was identified by immunoelectrophoresis, double diffusion in agar gel, sodium dodecyl sulphate-polyacrylamide gel electrophoresis and immunoblotting. The pure antigen displayed the electrophoretic mobility typical of antigen 5 and gave a single precipitin band in double diffusion with both monoclonal antibody and rabbit anti-pH5PPT hydatid fraction serum. Two bands of 66 and 56 kDa could be detected in the pure antigen 5 after sodium dodecyl sulphate-polyacrylamide gel electrophoresis when performed in non-reducing conditions: both bands were reactive with the monoclonal antibody in immunoblotting. After reduction with 2-mercaptoethanol, antigen 5 displayed one band only, of 39 kDa. Antigen 5 purified by this procedure was found to retain reactivity with human sera from hydatid patients in a DD5 test.

Animals↗
PubMed1987

Specific and cross-reactive antigens of Echinococcus granulosus hydatid cyst fluid.

The parasite antigens of Echinococcus granulosus hydatid cyst fluid have been characterised using the techniques of radioiodination, immunoprecipitation, SDS-PAGE, and immunoblotting. Five major subunit antigens of the parasite have been identified of relative molecular mass (Mr) 12,000, 16,000, two at 20,000, and 38,000 when reduced. The 12 and 16 kDa molecules are specific to E. granulosus and are excreted/secreted by both U.K. strains of the parasite and all human isolates examined, although not all hydatid disease patients produce antibodies to them. These molecules may be suitable for detection in specific immunodiagnosis. The 38 kDa molecule associates, via a disulphide linkage, with one of the 20 kDa molecules to form a single molecule of 60 kDa. This antigen is cross-reactive with human antibody to other cestode, trematode, and nematode parasites. Part of this cross-reactivity is associated with the presence of phosphorylcholine bound to the 38 kDa subunit.

Animals↗
PubMed1987

Echinococcus granulosus: occurrence of ecdysteroids in protoscoleces and hydatid cyst fluid.

Both free ecdysteroids and hydrolysable polar conjugated ecdysteroids were detected in protoscoleces of Echinococcus granulosus from the equine host, and in hydatid cyst fluid from the same source. Comparisons were made of hydatid cyst fluid from E. granulosus infections of three intermediate host species: horses, sheep and humans. Ecdysone and 20-hydroxyecdysone were identified in both protoscoleces and hydatid cyst fluids by high-performance liquid chromatography monitoring fractions by radioimmunoassay, and by capillary gas chromatography/mass spectrometry (selected ion monitoring). The free ecdysteroid fractions of hydatid cyst fluid from horses and sheep also contained several unidentified, chromatographically unique, immunoreactive compounds which were refractory to hydrolysis with a crude Helix pomatia aryl sulphatase enzyme preparation.

Animals↗
PubMed1987

A comparative study of UTP-D-glucose-1-phosphate uridylyl transferase in the cysts of Echinococcus multilocularis and the livers of infected and control Meriones unguiculatus.

Kinetic and physical parameters of UDP-glucose pyrophosphorylase were determined in Meriones unguiculatus infected with Echinococcus multilocularis metacestodes (cestoda). Studies were carried out on parasite cysts, and on livers from control and infected animals after purification of the enzyme by affinity chromatography on UTP-agarose. The enzyme from infected and control livers had km values for UTP of 0.01 mM and 0.5 mM, respectively; for glucose-1-phosphate values were 0.46 mM and 0.07 mM, respectively. On the other hand the enzyme from cysts was found to have a higher Km for UTP (1 mM) and for glucose-1-phosphate (1.5 mM) than from infected or non-infected livers. Physical characteristics (pI = 6 and Mr = 160,000) of UDP-glucopyrophosphorylases were the same in controls and infected host livers but were different from the cyst enzyme (pI = 7 and Mr = 251,000). These results provide evidence for the existence of significant differences between parasitic and host enzymes, which could possibly be exploited in chemotherapy.

Animals↗
PubMed1988

Production of a recombinant antigen of Echinococcus multilocularis with high immunodiagnostic sensitivity and specificity.

A cDNA library derived from mRNA of metacestodes from Echinococcus multilocularis was constructed in the Escherichia coli expression vector lambda gt11 and screened with human patients' sera. The recombinant proteins of 11 positive phages were further evaluated for their potential as immunodiagnostic reagent. One isolated clone (from lysogen II/3) synthesized a fusion protein which was rapidly degraded. This intracellular degradation process provided two distinct polypeptides with Mr of about 31,000 and 33,000, both showing strong binding activity with specific patients' antibodies. The diagnostic value of the II/3-antigen was evaluated by mini-Western-blot with sera from 41 patients infected with E. multilocularis and sera from 77 patients with other helminthic infections, resulting in a diagnostic sensitivity of 98% and an over-all specificity of 96%. These results suggest the usefulness of the recombinant II/3-antigen for immunodiagnosis of human alveolar echinococcosis.

Animals↗
PubMed1989

Isolation and partial characterization of species-specific and cross-reactive antigens of Echinococcus granulosus cyst fluid.

Two parasite antigens have been isolated from Echinococcus granulosus hydatid cyst fluid using hydrophobic interaction chromatography, anion exchange chromatography and gel filtration chromatography. Initial characterization of the antigens indicates that both are glycoproteins, of approximately 20 and 48 kDa (Eg20 and Eg48). When the two antigens were tested with a battery of antisera from patients with heterologous parasitic infections, only Eg20 was found to be specific for E. granulosus. The Eg48 antigen cross-reacted with the sera of 33% of E. multilocularis patients. In both antigens, some of the epitopes recognized by antibodies in the sera of hydatid patients were periodate-sensitive. This suggests the involvement of carbohydrates in at least some of the antigenic determinants. Due to the abundance of the Eg48 antigen in the hydatid cyst fluid, it would be the more practically useful antigen for disease diagnosis, especially in countries where only E. granulosus is endemic.

Animals↗
PubMed1989

Application of a recombinant Echinococcus multilocularis antigen in an enzyme-linked immunosorbent assay for immunodiagnosis of human alveolar echinococcosis.

A highly antigenic polypeptide fragment of the recombinant Echinococcus multilocularis antigen II/3 was produced in Escherichia coli and purified for application in enzyme-linked immunosorbent assay (ELISA). The antigen II/3-encoding 1.0 kb DNA sequence was reduced by sonication into smaller DNA fragments which were subsequently cloned into lambda gt11. Three clones could be isolated from the sublibrary, all synthesizing a recombinant antigen as a stable beta-galactosidase fusion protein. In a further step, the 0.6-kb insert from one positive clone was subcloned into the plasmid pAR 3038, which directed efficient synthesis of the antigen fused to only 11 amino acids from the N-terminus of the phage T7 major capsid protein. The plasmid-encoded antigen (antigen II/3-10) was purified from a bacterial cell extract and then tested in an ELISA. Using sera from 88 patients with an E. multilocularis-infection, a high diagnostic sensitivity of 90% was demonstrated. Investigation of sera from 220 patients with various helminthic infections showed a specificity of 99%, suggesting the suitability of the antigen II/3-10 as an immunodiagnostic tool.

Animals↗
PubMed1990

Analysis of the monohexosylceramide fraction of Echinococcus multilocularis metacestodes.

Monohexosylceramides of Echinococcus multilocularis metacestodes have been isolated and analyzed by thin-layer chromatography, gas-liquid chromatography and mass spectrometry. 90.9% of the parasite fraction was galactosylceramide; glucosylceramide was present at only 9.1%. The most important fatty acids were normal C16:0 and C26:0 fatty acids. The hydroxylated fatty acids of the ceramide part constituted 20.1% of the total, their major constituents were C18:0 and C26:0. The sphinganine accounted for 70.4% of long-chain bases, phytosphingosine and sphingosine were also detected. The importance of the long chain fatty acids and the presence of sphinganine in the monohexosylceramide fraction were discussed.

Animals↗
PubMed1990

Glycosphingolipids of Echinococcus multilocularis metacestodes.

Neutral and acid glycosphingolipids of Echinococcus multilocularis metacestodes that were obtained after intraperitoneal infection of Meriones unguiculatus have been analyzed by thin layer chromatography. Neutral and acid glycosphingolipids accounted for 95% and 5% of total glycosphingolipids, respectively. 12 different fractions were observed in the neutral glycosphingolipids extracts of the parasite. The most important was a monohexosylceramide fraction accounting for 56.4% of neutral glycosphingolipids. 9 different fractions were detected in gangliosides (acid glycosphingolipids). The fact that these glycosphingolipids were specific to the parasite was established by the analysis of different cell populations of the host. Glycosphingolipids were purified from control and parasite-infected gerbil blood cells as well as from peritoneal exudate cells of healthy gerbils after a non-specific immunostimulation. The chromatograms obtained with these extracts were totally different from the parasite. In addition, parasitosis was found to have no effect on the host blood cell glycosphingolipids.

Animals↗
PubMed1991

Structure of the Echinococcus multilocularis U1 snRNA gene repeat.

The gene encoding U1 snRNA in Echinococcus multilocularis has been cloned and sequenced. This gene is contained within a 1300-bp sequence which is tandemly repeated in the E. multilocularis genome. E. multilocularis U1 snRNA is 50-70% homologous to U1 snRNAs of other species. E. multilocularis U1 snRNA could assume a predicted secondary structure similar to that proposed for other U1 snRNAs, and appears shorter (157 bases) than the U1 snRNAs of higher eukaryotes (163-166 bases).

Amino Acid Sequence↗
PubMed1991

Molecular cloning of an Echinococcus granulosus protein expressing an immunogenic epitope of antigen 5.

cDNA was synthesized from RNA extracted from Echinococcus granulosus protoscoleces and cloned in the lambda gt11 expression vector. A pool of 5 E. granulosus patient sera was used to screen the library and allowed the selection of 13 clones. Ten of these were shown to be identical, among which clone 6 (Eg6) was chosen for further analysis. The nucleotide sequence (456-bp) presented an entire open reading frame coding for 152 amino acids. The fusion protein (FP6) was recognized by a mouse monoclonal antibody (EG 02 154/12) specific for E. granulosus antigen 5. Moreover, the presence of antibodies to FP6 seemed to be correlated to the ability of sera from hydatidosis patients to immunoprecipitate antigen 5. These results indicate that the cloned protein could be used as a standardized antigen for the diagnosis of hydatidosis.

Amino Acid Sequence↗