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mechanisms of evasion of schistosoma mansoni schistosomula to the lethal activity of complement.schistosomula of schistosoma mansoni became resistant to antibody-dependent complement damage in vitro after pre-incubation with normal human erythrocytes (nhue) whatever the abo or rh blood group. resistant parasites were shown to acquire host decay accelerating factor (daf), a 70 kda glycoprotein attached to the membrane of nhue by a gpi anchor. igg2a mab anti-human daf (ia10) immunoprecipitated a 70 kda molecule from 125i-labeled schistosomula pre-incubated with nhue and inhibited their resis ...19921285336
effect of glycoinositolphospholipid anchor lipid groups on functional properties of decay-accelerating factor protein in cells.the inositol ring in the glycoinositolphospholipid (gpi) anchor of human decay-accelerating factor (daf) is unmodified in nucleated cells, whereas it is fatty acid acylated in erythrocytes (ehu). to assess the effect of this and of the glycerol sn-2-associated acyl substituent on the abilities of daf to cell membrane incorporate and function, 1) endogenous (physiologically anchored) daf proteins bearing three- and two-"footed" gpi anchors were purified from ehu and hela cells and 2) synthetic da ...19921370460
fasciola hepatica: host responders and nonresponders to parasite glutathione s-transferase.fasciola hepatica glutathione s-transferase (fhgst) was isolated from adult worms by glutathione agarose affinity chromatography. sds-page shows three proteins of m(r) ranging from 29-27.8 kda. western immunoblot analyses using sds-page separated adult worm extracts and probed with a rabbit anti-fhgst antiserum reveal two bands in the same m(r) range. mice and rabbits immunized with purified fhgst develop copious amounts of anti-fhgst antibodies. moreover, antisera to f. hepatica adult worms and ...19921516666
excretory-secretory products of echinostoma paraensei sporocysts mediate interference with biomphalaria glabrata hemocyte functions.miracidia of echinostoma paraensei were cultured in medium containing 14c-labeled amino acids, allowed to transform into sporocysts, and their excretory/secretory products (e-s) were collected and characterized by sodium dodecyl sulfate polyacrylamide gel electrophoresis and autoradiography. effects of e-s on hemocytes of biomphalaria glabrata were also assessed. e-s collected during day 1 of culture (e-s1) contained several polypeptides, none of which were labeled, suggesting that e-s1 are larg ...19921738052
lytic activity from schistosomes: interactions with blood cells.1. the schistosome lytic agent hemolyzed animal red blood cells (rbcs) containing high concentrations of membrane phosphatidyl choline (dog, mouse, and rat) more efficiently than rbcs having no phosphatidyl choline (goat and sheep). 2. human mononuclear cells lost viability in the presence of the schistosome lytic agent. 3. preincubating the lytic agent with phosphatidyl choline or bovine serum albumin reduced its lytic activity. 4. extracellular albumin protected the rbcs from schistosome induc ...19911873980
comparative antigen analysis of different life stages of schistosoma mansoni by crossed immunoelectrophoresis.two-dimensional (crossed) immunoelectrophoresis was used for analysis of soluble antigen extracts obtained from the three developmental stages, cercariae, adult worms and eggs, of schistosoma mansoni by using homologous hyperimmune sera produced in sheep. the antigenic relationships between the three stages as well as the possible relationship to the intermediate snail host were studied. seven antigen components were shown to be shared between all three life stages of s. mansoni. furthermore, on ...19911937928
initial feasibility studies of the fast-elisa for the immunodiagnosis of fascioliasis.the falcon assay screening test enzyme-linked immunosorbent assay was adapted for the detection of antibodies to fasciola hepatica excretion-secretion (fhes) antigens in various animal models. pooled serum from 5 5-wk-old sheep infected with 400 f. hepatica metacercariae had high absorbance levels by 2 wk of infection and rose again at 8-10 wk. pooled serum from 5 6-wk-old holstein calves infected with 700 f. hepatica metacercariae had an increase in absorbance levels by 2 wk of infection, risin ...19912040949
role of regulatory peptides in parasitic platyhelminths and their vertebrate hosts: possible novel factors in host-parasite interactions. 19912057218
[effect of schistosoma mansoni infection on the immune reactions against heterologous antigens in mice].mice (balb/c or icr) were infected with schistosoma mansoni cercariae. after different intervals (mostly eight weeks) the following antigens were injected: a) sheep erythrocytes--b) dnp-thyroglobulin. afterwards the immune response against these antigens were checked by means of different methods (plaque assay, haemagglutination test, rosette technique). immune responses to these antigens were depressed in all cases compared to age matched uninfected mice but it was not possible to transfer this ...19902111964
isolation and characterisation of nucleic acids from the hydatid organisms, echinococcus spp. (cestoda).dna and rna in combination have been prepared and characterised from the hydatid disease organisms, echinococcus granulosus and echinococcus multilocularis. the dna obtained is of high molecular weight, pure and can be cleaved by restriction enzymes, thereby facilitating future production of genomic dna probes for studies of echinococcus gene expression. moreover, cloned dna segments from schistosoma mansoni hybridise strongly to echinococcus dna following restriction and southern blot analysis. ...19852414655
decay accelerating factor (daf) as the host antigen with protective activity to complement killing of schistosomula.the acquisition of host antigens by schistosoma mansoni was studied by evaluating the resistance of schistosomula to the complement attack mediated by lethal antibody. schistosomula cultured for 24 hours with intact human erythrocytes (n-hue) or ghosts of any type of abo or rh blood group, showed a marked resistance to complement damage. sheep red blood cells, pronase-treated n-hue or erythrocytes from patients with paroxysmal nocturnal hemoglobinuria, which are complement-sensitive cells, were ...19872474124
quantitative determination of circulating antigens in human schistosomiasis mansoni using an indirect hemagglutination assay.in serum and urine specimens collected from a group of schistosoma mansoni infected individuals from makundju, zaire, the schistosome circulating anodic antigen (caa) and the circulating cathodic antigen (cca) were quantitatively determined using an indirect hemagglutination reaction with sheep erythrocytes sensitized with mouse igm monoclonal antibodies directed against these circulating antigens. levels of caa in serum (up to 5 ng/ml) and cca in serum and urine (up to 50 ng/ml) were strongly c ...19892492777
vanadate sensitivity of na+, k+-atpase from schistosoma mansoni and its modulation by na+, k+ and mg2+.vanadate inhibitory effects on na+, k+-atpases from carcass of schistosoma mansoni and from lamb kidney outer medulla were compared in the presence of various concentrations of na+, k+ and mg2+. depending on the ionic conditions, the schistosomal na+, k+-atpase was 2.4- to 175-fold less sensitive to vanadate than the lamb kidney enzyme. in 100 mm na+, 3 mm k+ and 3 mm mg2+, schistosomal na+, k+-atpase was surprisingly resistant to vanadate (i50 = 944 microm). the difference in vanadate sensitivi ...19892543877
restriction enzyme mapping of ribosomal dna can distinguish between fasciolid (liver fluke) species.recognition sites for nine different restriction endonucleases were mapped on rdna genes of fasciolid species. southern blots of digested dna from individual worms were probed sequentially with three different probes derived from rdna of schistosoma mansoni and known to span between them the entire rdna repeat unit in that species. eighteen recognition sites were mapped for fasciola hepatica, and seventeen for fasciola gigantica and fascioloides magna. each fasciolid species had no more than two ...19892552311
genetic heterogeneity within echinococcus granulosus: isolates from different hosts and geographical areas characterized with dna probes.a segment of the ribosomal rna gene of schistosoma mansoni and a dna fragment specific to echinococcus granulosus, cloned in plasmids, have been used as dna probes to assess the extent of genetic variability within e. granulosus and some distinct strains have been identified. the dna analysis, involving restriction endonuclease digestion and southern blot hybridization with the probes, did not demonstrate any significant genetic variation within the u.k. horse/dog or sheep/dog strains but confir ...19892552377
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 id ...19852999590
effects of anti-schistosomal chemotherapy on immune responses, protection and immunity. iii. an effective regimen of praziquantel does not alter immune capabilities of normal mice.praziquantel is a broad spectrum anti-helminthic drug active against a variety of parasitic trematodes and cestodes. this report studies the effects of a schistosomacidal regimen of praziquantel on the generation of the cell-mediated and humoral response capabilities of normal, uninfected mice. three doses of 100 mg praziquantel/kg body weight at 4-hr intervals cured several strains of mice with schistosoma mansoni infections of several intensities. when this curative regimen was applied to norm ...19863080914
the regulation of trematode populations by density-dependent processes. 19873108179
schistosomal specific nephropathy leading to end-stage renal failure.in this study 17 patients, 11 with end-stage renal failure and six with nephrotic syndrome were selected. the selection criteria were presence of active intestinal schistosomiasis and absence of any surgical or other medical disease which could explain the renal disease. when examined by light microscopy, kidney biopsies showed membranoproliferative glomerulonephritis in nine, membranous in four, focal segmental glomerulosclerosis in two, sclerosing glomerulonephritis in one case, and no changes ...19873108566
cross-resistance between schistosoma mansoni and fasciola hepatica in sheep.five sheep were exposed to 5,000 s. mansoni cercariae percutaneously and the stools examined for 20 wk to determine patency. the sheep were found to be partially susceptible to a primary infection and showed great individual variations in their pathophysiological responses. all of the sheep acquired a patent infection with s. mansoni and eggs were first seen in feces 9 wk postexposure with no eggs detected after 14 wk. at necropsy 20 wk postexposure only dead s. mansoni worms were found. koh dig ...19883138395
the separation of complement inhibitors from patients with schistosomiasis or chagas' disease by gel filtration on sephadex g-200: a preliminary study.gel filtration through sephadex g-200 was used to detect anticomplement activity of sera from patients with schistosoma mansoni infections or chagas' disease. protein content, immunoglobulins and hemolysis-inhibiting activity were assessed in the chromatographic effluent. the proteins were distributed as usual among three regular peaks. the presence of igm (first peak) and igg (second peak) in the fractions was demonstrated by the ouchterlony method. no immunoglobulins were detectable in the thi ...19883144403
antibodies reactivity in human schistosoma mansoni disease: detection and functional activity.the detection and description of the functional activity of anti s. mansoni antibodies, and the relationship between five different antigen preparations, each corresponding to one immunological test for schistosomiasis, are described. this study, using functional assay, suggests that human antibodies detected by skin tests, direct lysis of sheep erythrocytes, complement fixation reaction, indirect immunofluorescent staining and complement-mediated death of schistosomules, show important dissimil ...19883151431
circulating antigens for assessing cure in schistosomiasis mansoni.an antigen capture enzyme-linked immunosorbent assay using antibodies made in rabbits and sheep to adult schistosoma mansoni extract antigens has been developed and evaluated as a diagnostic test for schistosomiasis. 25 of 42 patients with s. mansoni infections had detectable circulating antigen while sera from all of 45 normal subjects and patients with other parasitic infections did not react. when the 25 with antigenaemia were retested 3 months after treatment, all 21 who were cured were nega ...19883151529
identification of a 17-kilodalton fasciola hepatica immunodiagnostic antigen by the enzyme-linked immunoelectrotransfer blot technique.sera obtained from human patients, calves, sheep, and rabbits infected with fasciola hepatica were tested by the falcon assay screening test enzyme-linked immunosorbent assay (fast-elisa) and the enzyme-linked immunoelectrotransfer blot (eitb) techniques with fasciola hepatica excretory-secretory antigens in order to evaluate their immunodiagnostic potential. the study included sera from 13 patients infected with f. hepatica or a history suggesting fascioliasis, 5 patients infected and treated w ...19883182993
identification of a lymphokine that stimulates eosinophil differentiation in vitro. its relationship to interleukin 3, and functional properties of eosinophils produced in cultures.factors stimulating eosinophil differentiation in vitro have been studied by means of a liquid bone marrow culture system in which the number of eosinophils is estimated directly by morphology or indirectly by assay for eosinophil peroxidase. the results show that eosinophil colonies are not formed in agar, emphasizing the importance of the liquid culture system. three types of evidence identify a novel lymphokine, eosinophil-differentiating factor (edf). (a) coordinate analysis of lymphokine ac ...19853925072
identification of a human granulocyte functional antigen (gfa-2) involved in antibody-dependent cell-mediated cytotoxicity and phagocytosis.a human neutrophil- and eosinophil-specific surface antigen, gfa-2, has been found to be involved in the antibody-dependent cell-mediated cytotoxicity (adcc) to extracellular targets, and in phagocytosis. the monoclonal antibody (mab) wem-g11 was produced which recognizes the gfa-2 structure. this mab, when used as f(ab')2, stimulated human neutrophils to kill antibody-coated p815 cells and, in the case of human eosinophils, increased their cytotoxic effect on schistosomula of schistosoma manson ...19853989303
identification of antigenic schistosoma mansoni glycoproteins during the course of infection in mice and humans.the progression of humoral immune responses exhibited by mice during the year following exposure to schistosoma mansoni cercariae was established by studying radioimmunoprecipitations of adult male and cercarial glycoproteins. 35s-methionine metabolically-labeled adult s. mansoni male worm glycoproteins precipitated by sera of 14 mice were identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. the initial specific antibody response (week 5) was directed against 3 worm glycoprot ...19854003664
domestic and wild animals naturally infected with schistosoma mansoni in the gezira irrigated scheme, sudan.domestic and wild animals were examined for natural infection with human schistosomiasis in northern gezira, sudan. postmortem examination of animals in a number of slaughterhouses revealed no infections in either sheep or goats but schistosoma mansoni worms were found in two of the 98 cattle examined. nile rats (arvicanthus niloticus) were trapped and stray dogs were shot and examined for evidence of schistosome infection. the infection rate in nile rats was 4.9% (8/164) and in dogs 27.3% (15/5 ...19854032533
primary in vitro sensitization to heterogeneous soluble antigens of schistosoma mansoni adult worms.primary in vitro sensitization of normal mouse spleen cells was accomplished using a saline soluble heterogeneous antigenic preparation from the whole adult worms (swap) of schistosoma mansoni. a swap-specific rosette-forming cell (rfc) assay, using antigen on sheep erythrocytes, was used to detect sensitization due to s. mansoni infection and primary in vitro swap exposure. the latter exposure was facilitated by swap adsorption to the culture vessel via poly-l-lysine. rfc expression was maximal ...19826173445
fasciola hepatica: development of monoclonal antibodies and their use to characterize a glycocalyx antigen in migrating flukes.using mice harbouring early fasciola hepatica infections, six monoclonal antibodies were prepared against a tegumental antigen present in t1 granules and glycocalyx of flukes. blocking tests indicated that all monoclonals bound the same t1 epitope (or epitopes in close proximity on the antigen molecule), but this was not the determinant recognized by sheep and cattle. localization of antibody binding at light and electron microscope levels showed that t1-type antigen also occurred in metacercari ...19836194499
detection of ige in the sera of rodents: comparison of the applicability of elisa and ria.ria and elisa were compared for their ability to detect ige in different rodent species. with a sheep anti-rat ige antibody good correlation (p less than 0.001) between the 2 assay methods for ige was found in rats. ria failed to detect the ige of mastomys natalensis while elisa proved to be a suitable test. however, both tests failed to measure ige in sera of nile rats.19846371140
immunity of schistosomes using heterologous trematode antigens--a review.this review summarizes the field of cross-protection in schistosomiasis due to other parasitic infections and with subcellular fractions of the parasite trematodes. regarding parasitic infections, the clearest evidence of cross-protection to schistosoma mansoni was found with the trematodes, particularly with fasciola hepatica. evidence was also presented which demonstrated that the protective f. hepatica worm antigens were those which bound to antibodies to s. mansoni, and that as antigen purif ...19846382782
erythroadsorption and enzyme-linked immunoassays (eaia and elisa) for specific circulating antibodies and antigens in schistosomiasis.we developed a method of immunologic titration by erythroadsorption in order to assay anti-schistosoma mansoni soluble cercarial antigen igm antibodies and anti-s. mansoni soluble worm and egg antigen igg antibodies. this method was compared to the elisa technique. results obtained using the two techniques were similar, although the erythroadsorption technique was less sensitive for identifying igm during the acute phase of the disease. both assay systems revealed a correlation between the level ...19846385815
angiotensin ii stimulation of granuloma macrophage phagocytosis and actin polymerization in murine schistosomiasis mansoni.in murine schistosomiasis, components of the renin-angiotensin system are present in isolated liver granulomas. furthermore, granuloma macrophages have receptors for angiotensin ii (aii). these observations with other evidence suggest that angiotensins function in immunoregulation. since aii can stimulate actin-myosin interactions and since macrophages have contractile proteins, it was determined whether aii could alter the phagocytic activity of granuloma macrophages. aii, at concentrations whi ...19846541527
a comparative study on the preparation of immunoglobulin-galactosidase conjugates.for the application of beta-d-galactosidase-immunoglobulin conjugates in the enzyme-linked immunosorbent assay (elisa), four techniques for the preparation of such conjugates were compared. sheep immunoglobulin (ig) (against soluble egg antigens of the trematode schistosoma mansoni) was coupled to beta-d-galactosidase by means of 1) glutaraldehyde treatment, 2) the heterobifunctional reagent n-succinimidyl 3-(2-pyridyldithio) propionate (spdp), and 3,4) two different procedures using the couplin ...19816798103
non-specific cell mediated immunity in patients infected with schistosoma mansoni in kenya.parameters of in vitro cell-mediated immunity (cmi) have been measured in the local kenyan population infected with schistosoma mansoni. lymphocyte responses to the non-specific t cell mitogens concanavalin a (con a) and phytohaemagglutinin (pha) were reduced in about 60% of schistosomiasis patients. lymphocytes from control uninfected, and s. mansoni-infected donors formed equal numbers of spontaneous rosettes with sheep red blood cells, indicating that there was no over-all reduction in the pe ...19826980505
schistosomiasis mansoni in baboons. vi. plastic-adherent-cell suppression of the primary in vitro antibody response of peripheral blood mononuclear cells to a heterologous antigen (srbc) during chronic infection.peripheral blood mononuclear cells (pbmc) from five of six baboons (papio cynocephalus) with chronic schistosomiasis mansoni showed a marked reduction in the ability to generate anti-sheep erythrocyte (srbc) plaque-forming cells (pfc) after primary in vitro immunization as compared to the pfc responses of pbmc from normal (non-infected) baboons. removal of the plastic-adherent (plad) cells from the pbmc of these animals results in a population of cells capable of responding to in vitro immunizat ...19827102913
applicability of sol particle immunoassay (spia) for detection of schistosoma mansoni circulating antigens. 19827188147
immunoregulation by schistosoma mansoni.schistosoma mansoni is known to release an inhibitory factor of lymphocyte proliferation elicited in vitro. the effect of this dialyzable schistosome incubation product (dsip) was tested in vivo on different aspects of the cell-mediated immune response. first, the dsip injected into c57b1/6 mice markedly inhibited the delayed type hypersensitivity to sheep red blood cells (srbc). furthermore, the dsip injected into s. mansoni infected fisher rats at the beginning of the infection induced an inhi ...19817309493
vaccination of sheep against fasciola hepatica with glutathione s-transferase. identification and mapping of antibody epitopes on a three-dimensional model of the antigen.the glutathione s-transferases (fhgst) of the liver fluke fasciola hepatica have been identified as novel vaccine candidates that protect sheep against a fluke infection. with the use of overlapping peptides covering the predicted amino acid sequences of four fhgst cdnas, we have defined the linear epitopes recognized by polyclonal antibody from sheep vaccinated with fhgst. dominant and minor epitopes were found to be present on all four of the sequences although some epitopes were shown to be s ...19947509829
functional and antigenic similarities between a 94-kd protein of schistosoma mansoni (scip-1) and human cd59.schistosomiasis is a parasitic disease affecting approximately 200 million people, primarily in the third world. schistosoma mansoni, one of the causative agents of this disease, parasitize the human mesenteric and portal blood systems while successfully evading host immune responses. during parasite penetration into the mammalian host and shortly afterwards, the larvae rapidly convert from being sensitive to being resistant to c-mediated killing. treatment of the c-resistant parasitic forms wit ...19947513011
binding of gpi-pld-treated daf to the surface of schistosoma mansoni schistosomula.decay accelerating factor (daf,cd55) is a 70-kda glycosylphosphatidylinositol (gpi)-anchored protein that protects human erythrocytes (hue) from complement-mediated damage by regulation of the c3-convertase. purified human daf can be incorporated into sheep red blood cell (srbc) membrane and confer complement resistance on these daf-deficient cells. here, we demonstrate that normal hue or their stroma (hues) incubated at 37 degrees c for 24 h release soluble daf in a biologically active form int ...19947521707
detection of excretory-secretory circulating antigens in sheep infected with fasciola hepatica and with schistosoma mansoni and f. hepatica.two groups of sheep were exposed to fasciola hepatica and schistosoma mansoni/f. hepatica infections, respectively, to determine the time of appearance of f. hepatica circulating excretory-secretory (fhes) antigens. five sheep were infected orally with 400 f. hepatica metacercariae. five additional sheep were infected first percutaneously with 5000 s. mansoni cercariae, and 10 weeks later orally with 400 f. hepatica metacercariae. antigen detection was performed in the two groups by a double ant ...19957632228
schistosoma mansoni circulating polysaccharide and protein antigens recognized by sheep antisera in patients with different clinical forms of schistosomiasis before and after treatment.two sheep antisera, one of which raised against polysaccharide (po) and other against protein (pt) components of schistosoma mansoni adult worms, were assessed by elisa for their ability to detect circulating parasite antigens in patients with different clinical forms of chronic schistosomiasis mansoni. the former antiserum detected parasite antigens in liver granulomata and the latter in renal glomeruli from schistosomiasis patients and mice experimentally infected with s. mansoni. in general, ...19947732262
[rflp analysis of dna from echinococcus granulosus collected from four provinces/autonomous region in china].a fragment of the ribosomal rna gene of schistosoma mansoni psm889 and two dna fragments specific to echinococcus granulosus phd5 and peg18 have been used as dna probes to assess the extent of genetic variability within e. granulosus. the dna analysis, including restriction endonuclease digestion and southern blot hybridization with the probes, did not demonstrate any genetic variation among e. granulosus collected from sheep in xinjiang, qinghai, gansu and ninxia. similarly, there was no geneti ...19937909504
echinococcus granulosus: partial characterization of the conductive properties of two cation channels from protoscoleces of the ovine strain, reconstituted on planar lipid bilayers.two cationic channels present in the microsomal fraction from echinococcus granulosus protoscoleces of the sheep strain were studied in planar bilayer reconstitution experiments. a whole-worm homogenate was subjected to differential centrifugation and the postmitochondrial supernatant was laid on the top of a discontinuous sucrose gradient. the 15-30% (w/v) membrane fraction, enriched in nadph-cytochrome c reductase, exhibited the highest fusion rate, two cationic channels being most frequently ...19958542996
stem cell factor dependent hyperplasia of mucosal-type mast cells but not eosinophils in schistosoma mansoni-infected rats.stem cell factor (scf) is a growth factor with multiple activities which acts on numerous cell types including primordial germ cells, haemopoietic stem cells, melanocytes and mast cells. scf is critical for the development of the mast cell hyperplasia associated with infection with the intestinal parasites nippostrongylus brasiliensis and trichinella spiralis. in the present study we have assessed the role of scf in the mast cell and eosinophil responses to schistosoma mansoni in the rat by bloc ...19958817606
the immune response of trypanosoma gambiense-infected mice to schistosoma whole worm antigens.heterologous humoral and cellular immune response to schistosoma mansoni and s. bovis antigens were investigated in tryponosoma gambiense-infected mice in order to understand the concurrent immune response to both parasites. immune response as measured by the indirect haemagglutination test (iha), spontaneous sheep red blood cell rosette formation with b-lymphocytes and the mean number of t-lymphocytes forming rosettes with aet-treated srbc to the schistosome antigens, was significantly depresse ...19969532305
fasciola hepatica: characterization and cloning of the major cathepsin b protease secreted by newly excysted juvenile liver fluke.proteolytic activity present in the excreted/secreted (es) material of newly excysted juvenile (nej) fasciola hepatica was biochemically analyzed. by gelatin substrate sds-page, only one region of activity was observed in the nej es material at a molecular mass of 29 kda. both the secreted cathepsin l from adult fluke and the 29-kda proteolytic activity of nej es show a common ph optimum of 7.5, a cysteine protease inhibition profile, and preference for the n-benzyloxycarbonyl (z)-phe-arg-nhmec ...19989538862
characterisation of fasciola hepatica cytochrome c peroxidase as an enzyme with potential antioxidant activity in vitro.cytochrome c peroxidase oxidises hydrogen peroxide using cytochrome c as the electron donor. this enzyme is found in yeast and bacteria and has been also described in the trematodes fasciola hepatica and schistosoma mansoni. using partially purified cytochrome c peroxidase samples from fasciola hepatica we evaluated its role as an antioxidant enzyme via the investigation of its ability to protect against oxidative damage to deoxyribose in vitro. a system containing feiii-edta plus ascorbate was ...199910404259
core alpha1-->3-fucose is a common modification of n-glycans in parasitic helminths and constitutes an important epitope for ige from haemonchus contortus infected sheep.synthesis of parasite specific ige plays a critical role in the defence against helminth infections. we report here that ige from serum from schistosoma mansoni infected mice and haemonchus contortus infected sheep recognizes complex-type n-glycans from arabidopsis thaliana, which contain r-glcnacbeta1-->4(fucalpha1-->3)glcnacbeta1-asn (core alpha1-->3-fuc) and xylbeta1-->2manbeta1-->4glcnacbeta1-r (core beta1-->2-xyl) modifications, and honeybee phospholipase a2, which carries n-glycans that co ...199910601665
fasciola hepatica miracidia are dependent on respiration and endogenous glycogen degradation for their energy generation.it is generally accepted that free-living stages of parasitic helminths are dependent on aerobic degradation of endogenous energy sources for their energy generation. this concept, however, is not the result of extensive experimental evidence, but originated mainly intuitively as oxygen is widely available in their habitat and these stages generally have a small size. schistosoma mansoni, the sole parasitic helminth whose energy metabolism has been studied throughout its life-cycle indeed has ae ...200111272647
vaccination-induced protection of lambs against the parasitic nematode haemonchus contortus correlates with high igg antibody responses to the ldnf glycan antigen.lambs respond to vaccination against bacteria and viruses but have a poor immunological response to nematodes. here we report that they are protected against the parasitic nematode haemonchus contortus after vaccination with excretory/secretory (es) glycoproteins using alhydrogel as an adjuvant. lambs immunized with es in alhydrogel and challenged with 300 l3 larvae/kg body weight had a reduction in cumulative egg output of 89% and an increased percentage protection of 54% compared with the adju ...200312907692
vaccination against fasciola hepatica infection using a schistosoma mansoni defined recombinant antigen, sm14.fasciola hepatica is the causative agent of fasciolosis in many areas in america, europe, africa, asia and australia. there is an urgent need for improved methods to control the parasite's transmission. we describe the use of an experimental vaccine based on a recombinant antigen cloned from another parasite, schistosoma mansoni (sm14), that induces high levels of cross protection in mice against both s. mansoni and f. hepatica. sheep and mice vaccinated with sm14 were significantly protected ag ...200312911521
inhibition of the complement membrane attack complex by schistosoma mansoni paramyosin.larvae and adults of the parasitic blood fluke schistosoma mansoni are resistant to killing by human complement. an earlier search by parizade et al. for a schistosome complement inhibitor identified a 94-kda surface protein which was named scip-1 (m. parizade, r. arnon, p. j. lachmann, and z. fishelson, j. exp. med. 179:1625-1636, 1994). following partial purification and analysis by mass spectrometry, we have determined scip-1 to be a surface-exposed form of the muscle protein paramyosin. as s ...200314573661
resistance as a tool for discovering and understanding targets in parasite neuromusculature.the problem of anthelmintic resistance prevents efficient control of parasites of livestock and may soon compromise human parasite control. research into the mechanisms of resistance and the quest for diagnostic tools to aid control has required research that focuses on field resistance. on the other hand, resistant worms, including those kept in the laboratory, provide useful tools for studying drug action, especially at neuromuscular targets in worms. while the needs and directions of these re ...200516569289
identification and characterization of an asparaginyl proteinase (legumain) from the parasitic nematode, haemonchus contortus.asparaginyl proteinases (or legumains) are a recently identified, novel class of cysteine proteinase which specifically hydrolyse peptide bonds after asparagine residues. legumains have been implicated in the activation of cysteine proteases, particularly cathepsin b-like proteinases which are thought to help degrade the bloodmeal in blood-feeding helminths such as schistosomes, hookworms and other nematode species. an est sequence representing a full-length legumain was identified from the haem ...200616650340
thermostability of heterophile antibodies from human sera infected with schistosoma mansoni and geo-helminths. an immuno-metric statistical analysis.antibody in human sera that induces lysis of sheep erythrocytes in hemolytic assay was investigated. the present study showed that the presence in serum of the thermostable cytolytic anti-sheep red blood cells antibodies is dependent on the schistosoma mansoni infection, and this is more frequent in adults than in children. the thermostable characteristic of hemolysins in normal sera was not dependent on the presence of ascaris lumbricoides, trichuris trichiura or hookworm geo-helminths. further ...200616847506
specific inhibitors of mitogen-activated protein kinase and pi3-k pathways impair immune responses by hemocytes of trematode intermediate host snails.to characterize molecular mechanisms regulating snail cellular immune responses, the contributions of mitogen-activated protein kinases (mapks) and phosphatidylinositol 3-kinase (pi3-k) were examined in hemocytes of the trematode intermediate host snails biomphalaria glabrata and lymnaea stagnalis. simultaneous measurement of phagocytosis/encapsulation and h2o2 production by hemocytes in the presence or absence of specific signal transduction inhibitors was used to assess the role of extracellul ...200716926049
biochemical characterisation of the recombinant peroxiredoxin (fheprx) of the liver fluke, fasciola hepatica.the parasitic helminth fasciola hepatica secretes a 2-cys peroxiredoxin (prx) that may play important functions in host-parasite interaction. recombinant peroxiredoxin (fheprx) prevented metal-catalyzed oxidative nicking of plasmid dna and detoxified hydrogen peroxide when coupled with escherichia coli thioredoxin and thioredoxin reductase (k(cat)/k(m)=5.2 x 10(5)m(-1)s(-1)). enzyme kinetic analysis revealed that the catalytic efficiency of fheprx is similar to other 2-cys peroxiredoxins; the en ...200616938293
mapping of the complement c9 binding domain in paramyosin of the blood fluke schistosoma mansoni.schistosomes are believed to evade complement-mediated damage by expression of complement inhibitory proteins. our previous results [deng, j., gold, d., loverde, p.t., fishelson, z., 2003. inhibition of the complement membrane attack complex by schistosoma mansoni paramyosin. infect. immun. 71, 6402-6410.] have demonstrated that paramyosin (pmy) of the blood fluke s. mansoni binds to the human complement proteins c8 and c9, inhibits complement activation at the terminal stage and protects the pa ...200717123534
aspartic protease activities of schistosomes cleave mammalian hemoglobins in a host-specific manner.we examined the efficiency of digestion of hemoglobin from four mammalian species, human, cow, sheep, and horse by acidic extracts of mixed sex adults of schistosoma japonicum and s. mansoni. activity ascribable to aspartic protease(s) from s. japonicum and s. mansoni cleaved human hemoglobin. in addition, aspartic protease activities from s. japonicum cleaved hemoglobin from bovine, sheep, and horse blood more efficiently than did the activity from extracts of s. mansoni. these findings support ...200717294005
production of monoclonal antibodies against the 8 kda subunit of echinococcus granulosus antigen b (egagb8/2) using dna immunization.cystic echinococcosis (ce), an endemic cosmopolitan zoonotic helminthic disease caused by the larval stage of echinococcus granulosus, lacks reliable diagnostic tools that fulfill the criteria of high sensitivity and specificity. antigen b (agb), a thermostable lipoprotein that constitutes a considerable fraction of the cystic hydatid fluid (hf), is being considered as a suitable source for vaccination and immunodiagnosis of ce due to its high specificity. genetic immunization was used to immuni ...200818803505
the biotechnology-value chain: development of sm14 as a schistosomiasis vaccine.in the 1990s, who/tdr created a product development program and initiated collaborations with other major international donors to promote rapid vaccine development and other tools for the control of endemic diseases. this "push strategy" was chosen to achieve effective research projects fostering innovation in the context of rapid product development. in the field of vaccine development, the aim was to bring forth ways and means to immunize against the most important human parasite diseases. alt ...200818834847
elucidating the transcriptome of fasciola hepatica - a key to fundamental and biotechnological discoveries for a neglected parasite.liver flukes of animals are parasitic flatworms (platyhelminthes: digenea) of major socioeconomic importance in many countries. key representatives, such as fasciola hepatica and f. gigantica, cause "liver fluke disease" (= fascioliasis), which is of major animal health significance worldwide. in particular, f. hepatica is a leading cause of production losses to the livestock (mainly sheep and cattle) and meat industries due to clinical disease, reduced weight gain and milk production, and death ...201020006979
proteomic analysis of embryonic fasciola hepatica: characterization and antigenic potential of a developmentally regulated heat shock protein.fasciola hepatica is responsible for human disease and economic livestock loss on a global scale. we report the first post-genomic investigation of cellular proteins expressed by embryonic f. hepatica via two-dimensional electrophoresis, image analysis and tandem mass spectrometry. antioxidant proteins and protein chaperones are prominently expressed by embryonic f. hepatica. molecular differences between the egg and other characterized f. hepatica lifecycle stages were noted. furthermore, prote ...201020089359
identification of immunodominant th1-type t cell epitopes from schistosoma japonicum 28 kda glutathione-s-transferase, a vaccine candidate.th1-type cytokines produced by the stimulation of th1-type epitopes derived from defined schistosome-associated antigens are correlated with the development of resistance to the parasite infection. schistosoma mansoni 28 kda glutathione-s-transferase (sm28gst), a major detoxification enzyme, has been recognized as a vaccine candidate and a phase ii clinical trial has been carried out. sheep immunized with recombinant schistosoma japonicum 28gst (sj28gst) have shown immune protection against the ...200516270154
purification, kinetics and inhibition by antimonials of recombinant phosphofructokinase from schistosoma mansoni.we reported before on the cloning of a cdna encoding s. mansoni pfk. in the present investigation we established optimal conditions for expression of the enzyme in insect cells with high yield. the recombinant pfk was purified to homogeneity. kinetic properties of the pure enzyme were studied with respect to its two substrates, fru-6-p and atp, and were compared with properties of mammalian pfk. atp inhibited the parasite enzyme only at concentrations higher than those which inhibited mammalian ...19968898332
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