bluuebunny/crossref_metadata_2025_split huggingface dataset:
Schistosoma mansoni: circulating and pulmonary leucocyte responses related to the induction of protective immunity in mice by irradiated parasites
Authors: Menson Essie N. , Coulson Patricia S. , Wilson R. A. 
Published: June 2009

SummaryThe leucocyte responses in peripheral blood and pulmonary airways are described following vaccination of mice with radiation-attenuated parasites, and subsequent challenge with normal parasites. Percutaneous vaccination stimulated a large and sustained expansion of the circulating lymphocyte pool, more marked than after intradermal vaccination with lung schistosomula which induced comparable levels of resistance. Macrophages and lymphocytes infiltrated the pulmonary airways in response to vaccination by both routes, the lymphocytes being particularly abundant after intradermal vaccination. Exposure of mice to an equivalent number of normal cercariae induced an earlier lymphocytosis of short duration; far fewer macrophages and lymphocytes infiltrated the lungs than after vaccination. An intense but transient pulmonary eosinophilia peaked at 3 weeks after primary exposure to either normal or attenuated parasites. Percutaneous challenge of vaccinated mice elicited higher levels of circulating lymphocytes than challenge of unsensitized controls. However, whilst leucocyte numbers of all cell types were still elevated in the airways at challenge as a consequence of vaccination, no further cellular recruitment was observed coincident with parasite elimination. Our data are compatible with the hypothesis that the mechanism of immunity in once-vaccinated mice involves a T lymphocyte-macrophage interaction triggered by antigen release from lung schistosomula.
Spatial and temporal variation in the infracommunity structure of helminths of Apodemus sylvaticus(Rodentia: Muridae)
Authors: Montgomery S. S. J. , Montgomery W. I. 
Published: June 2009

SummaryMean species richness and diversity of the helminth infracommunity of Apodemus sylvaticus in woodland areas of Co. Down, Northern Ireland, varied in time and space. Variation in infracommunity structure among individual hosts, however, always accounted for more than 60% of the variation in the data from different places or different times. Helminth species richness increased with increasing population density, the percentage of the host population 16 weeks old or older, and the proportion of the host population with animal material in their stomachs, at two sites monitored over 33 months. The basis for spatial variation in infracommunity structure is less certain but host dynamics and differences in diet are likely to play some role. It is concluded that analysis at the infracommunity level focuses closely on the potential for species interactions and overlap in resource utilization. Infracommunity structure, at least in the case of A. sylvaticus, varies markedly in time and space and between individual hosts. Such variation should not be ignored in comparative studies.
The effect ofBlastocrithidia triatomae(Trypanosomatidae) on the midgut of the reduviid bugTriatoma infestans
Authors: Jensen C. , Schaub G. A. , Molyneux D. H. 
Published: June 2009

SummaryThe pathogenic flagellateBlastocrithidia triatomaedisrupts the digestion ofTriatoma infestans; the midgut ultrastructure of bugs infected with the flagellate and of uninfected bugs is compared. Third or fourth instar larvae were dissected either unfed or 1 week after feeding.In all uninfected bugs extracellular membrane layers (e.m.l.) covered the apical microvillar border of the epithelial cells. Some midgut regions of bugs infected withB. triatomaeappeared normal but often adjacent cells showed pathological effects. In affected cells the e.m.l. and the microvilli and finally the cells themselves were reduced or destroyed. Correlated with these observations of pathogenicity the method of attachment of parasites changed. When the e.m.l. were present only rarely were flagella found, but on extracellular membrane-free cellsB. triatomaeattached by flagellar enlargement to the microvillar border or, if this was reduced, to the apical host cell membrane. No hemidesmosome-like plaques were found at the attachment site. Although some flagella were inserted into the apical region of the cells no intracellular flagellates were observed.
Schistosoma mansoni:evidence that site-dependent host responses determine when and where vaccine immunity is expressed in different rodent species
Authors: Delgado V. S. , McLaren D. J. 
Published: June 2009

SummaryLaboratory rodents vaccinated with highly irradiated cercariae ofSchistosoma mansonidevelop significant levels of specific acquired resistance yet effect challenge elimination in different organs. Mice and guinea-pigs are at opposite ends of the spectrum in this respect since, in our hands, vaccinated mice kill challenge parasites in the skin whereas vaccinated guinea-pigs kill challenge parasites predominantly in the liver. To determine whether this phenomenon is host-dependent (site) or parasite-dependent (stage), we have transferred worms harvested from mice or guinea-pigs into vaccinated recipient guinea-pigs. The results show that mouse-derived 5-day lung worms and 9-day liver worms that are essentially refractory to vaccine resistance in mice are indeed susceptible to vaccine resistance in guinea-pigs. Identical levels of susceptibility were recorded for lung-stage larvae introduced via the foot vein so as to experience lung and liver mechanisms, or via the mesenteric vein to bypass the lung, thereby confirming that vaccine resistance in guinea-pigs operates in the liver. Mouse worms and guinea-pig worms exhibited equivalent levels of susceptibility at all stages of development. Thirteen-day-old larvae from either donor species were on the border-line of vulnerability, while 20-day-old worms were totally refractory to vaccine immunity in guinea-pigs. These data show that vaccine immunity in different rodent species is a site-dependent, rather than a stage-dependent phenomenon. There is, however, an upper age limit of schistosome vulnerability which is common to worms harvested from different donor species.
Characterization of major surface and excretory-secretory immunogens ofTrypanosoma cruzitrypomastigotes and identification of potential protective antigen
Authors: Ouaissi M. A. , Taibi A. , Cornette J. , Velge P. , Marty B. , Loyens M. , Esteva M. , Rizvi F. S. , Capron A. 
Published: June 2009

SummaryThe surface antigens ofTrypanosoma cruzitrypomastigotes were identified by immunoprecipitation and were compared with metabolically labelled excretory—secretory products (ES) released by the parasitesin vitro. A series of major immunogenic components in the ES antigens were revealed (160 kDa, 130 kDa and 80–110 kDa). The trypomastigote surface also bears the 130 kDa band and the 80–110 kDa complex. Competition experiments demonstrated the common antigenic structure of the ES and the surface antigens. Two-dimensional analysis of ES antigens immunoprecipitated by human Chagasic serum revealed several spots in the 80–110 kDa region with a wide range of isoelectric points (PI between 5·4 and 6·7). This reflects a charge heterogeneity of these polypeptides. The trypomastigote 85 kDa polypeptide was also identified in the ES antigens by using a monoclonal antibody against this antigen. Two-dimensional analysis of the 85 kDa proteins shed from the surface of trypomastigotes and immunoprecipitated by the monoclonal antibody 155D3 showed 2 major spots: a major part of the 85 kDa polypeptide was found at pH 6·5–6·6, whereas a substantial amount of the antigen was found at pH 5·7. An additional component with molecular weight of approximately 58 kDa and isoelectric points of 6·5 and 6·6, was also visualized. Detection of the 85 kDa polypeptide circulating in serum from patients with acute and chronic Chagas' disease was achieved using an enzyme-linked immunosorbent assay. In addition, the data obtained showed that a polyclonal antibody to the 85 kDa polypeptide could be used to passively induce a partial protection of Fischer rats against acute lethal infection. Thus, the antigens recognized by polyclonal antibody appear to play a role in the development of protective immunity againstT. cruzi.
Blocking factors and the isolation of glutathione transferases from Hymenolepis diminuta (Cestoda: Cyclophyllidea)
Authors: Brophy P. M. , Barrett J. 
Published: June 2009

SummaryFour acidic glutathione (GSH) transferase forms were isolated from the cytosol of the adult cestode Hymenolepis diminuta by hydroxylapatite chromatography, glutathione-affinity chromatography and chromatofocusing, pH 7–5. The enzymes were dimers of subunit size approximately 24 kDa and accounted for at least 3% of the total soluble protein. The major GSH transferase had limited catalytic activity but may interact with a range of ligands and function as a binding/passive detoxification protein. An endogenous factor interfered with the binding of the crude cytosolic GSH transferase activity to glutathione-dependent affinity matrices but, following partial purification, the GSH transferase activity successfully interacted with the glutathione affinity matrix.
Evidence for widespread occurrence of antibodies toEncephalitozoon cuniculi(Microspora) in man provided by ELISA and other serological tests
Authors: Hollister W. S. , Canning E. U. , Willcox A. 
Published: June 2009

SUMMARYThe enzyme-linked immunosorbent assay (ELISA) was used to survey human sera for antibodies toEncephalitozoon cuniculiusing spores obtained fromin vitrocultures as antigen. Sera were obtained from patients with tropical diseases, neurological and renal disorders, patients who were HIV positive and those who had been tested for HIV but found to be negative. Sera from inhabitants of the village of Jali, The Gambia and from healthy blood donors were also examined. Numerous sera from all groups except the blood donors gave positive ELISA reactions at dilutions of 1:400. On titration, those with titres of 1:400 were reclassified as negative. Antibody titres of 1:800 and above were considered to be indicative of past or present infections withE. cuniculi. Many of these ELISA seropositives were also positive by IFAT or PAP. When examined by Western blotting of SDS–PAGE protein profiles ofE. cuniculispores, sera from many patients who had a tropical association reacted with the characteristic profiles shown by known positive mouse and rabbit sera. Others in the tropical group showed antibody binding to some but not all of the immunodominant polypeptides and yet others were negative in spite of their reactivity in the ELISA, IFAT or PAP test. Less agreement between ELISA and Western blotting results was obtained with the other groups of patients, although reactivity with one or more of the major polypeptide bands was sometimes seen. Serum from one blood donor, examined by ELISA and Western blotting, was positive. Differences in the methods of antigen preparation and of epitopes recognized by individuals may account for different reactivities in the tests. It is concluded that infections ofE. cuniculiare common in the tropics and that reactivations of these infections might be a hazard to AIDS patients.
The larvicidal activity of cyclosporin A againstSchistosoma mansoniin mice
Authors: Munro G. H. , Brannan L. R. , Chappell L. H. , Thomson A. W. , McLaren D. J. 
Published: June 2009

SUMMARYTreatment of BALB/c or MF1 mice with cyclosporin A (CsA) around the time of infection withSchistosoma mansoniconferred almost complete protection. The migration kinetics of L-[75Se]selenomethionine-labelled infective cercariae were investigated by compressed tissue autoradiography. Similar levels of skin penetration were achieved by cercariae in control and drug-treated individuals. CsA arrested 87–94% of the worms in the skin and ultimately all of these died in this site. Few worms (7–14%) migrated from the skin to the lungs and none completed migration to the liver. Nevertheless, the autoradiograms revealed a limited degree of lateral cutaneous migration by the worms present in the skins of CsA-treated mice. Results of perfusion recovery experiments carried out during the course of infection reinforced the tracking data.
Activation and inhibition of the brush-border membrane-bound alkaline phosphatase activity of Hymenolepis diminuta (Cestoda) by divalent cations
Authors: Pappas P. W. 
Published: June 2009

SUMMARYIn the absence of exogenous divalent cations, the isolated brush-border plasma membrane of Hymenolepis diminuta possesses alkaline phosphatase activity (APA). APA is stimulated in the presence of exogenous Mg2+ and inhibited by low concentrations of Zn2+ or high concentrations of Ca2+, and inhibition of APA by Zn2+ is reversed by both Mg2+ and Ca2+. APA is inhibited by ethylenediamine tetraacetic acid (EDTA), ethyleneglycol-bis-(β-aminoethyl ether) N, N′-tetraacetic acid, and 1, 10-phenanthroline in time- and concentration-dependent fashions, with EDTA being the most effective inhibitor. Following treatment with EDTA, APA is restored by Mg2+ and, to a lesser extent, by Ca2+, but not by Zn2+. Thus, APA represents a Mg2+-dependent enzyme that can be partly activated by Ca2+ but only in the absence of Mg2+.
Large-scale production ofPlasmodium vivaxsporozoites
Authors: Ponnudurai T. , Lensen A. H. W. , van Gemert G. J. , Bolmer M. , van Belkum A. , van Eerd P. , Mons B. 
Published: June 2009

SUMMARYMass-scale production ofPlasmodium vivaxsporozoites inAnopheles stephensiwas achieved using the chimpanzee (Pan troglodytes) as a source of infective blood. Membrane feeding was as successful as feeding mosquitoes directly on the animal so long as the time between drawing the blood and feeding was restricted to 45 min. Longer delays such as 2–3 h resulted in loss of infectivity in terms of oocyst production. The selected strain ofA. stephensiwas highly susceptible toP. vivax(Chesson strain). A strain ofA. stephensirelatively refractory toP. falciparumshowed no cross-refractoriness toP. vivax. Mixed infections ofP. falciparumandP. vivaxdid not interfere with each other in their development inA. stephensi. A second normal blood meal to mosquitoes infected withP. vivaxincreased the yield of salivary gland sporozoites.
Genomic divergence in the ecologically differentiated English freshwater and marine strains of Pomphorhynchus laevis (Acanthocephala: Palaeacanthocephala): a preliminary investigation
Authors: Munro M. A. , Reid A. , Whitfield P. J. 
Published: June 2009

SUMMARYIn and around the British Isles, three biologically specialized strains of the fish acanthocephalan Pomphorhynchus laevis have been recognized, each differing in geographical distribution and both final and intermediate host utilization. Six restriction endonuclease digests of the genomic DNA of the English freshwater and marine strains were compared by genomic cross-hybridization using the randomly sheared and radio-isotope labelled genomic DNA of freshwater P. laevis, and also by using a heterologous isotope labelled ribosomal DNA probe. Autoradiographs of hybridized Southern blots provided evidence for considerable homogeneity in the total repetitive DNA of the two strains as well as some preliminary evidence for possible restriction fragment length polymorphisms using EcoR I and Pvu II.
Action of cyclosporin A on the tapewormHymenolepis diminutain mice
Authors: Wastling J. M. , Gerrard D. , Walker J. , Chappell L. H. 
Published: June 2009

SUMMARYCyclosporin A (CsA), administered in 5 daily subcutaneous doses of 50 mg/kg to MF1 mice immediately following infection withHymenolepis diminutaenhanced parasite growth relative to controls. Drug administered at 24 h intervals for 10 days, and thereafter every 48 h to MF1 and CBA/Ca mice infected withH. diminuta, increased worm survival and growth, delayed host-mediated expulsion of the parasite and enabled some worms to develop to patency. Worm survival and weight both increased in a dose-dependent manner following daily CsA treatment of infected CBA/Ca and BALB/c mice (0–150 mg/kg CsA/day). Delay in parasite elimination was accompanied by increased frequency of worm-attachment in the anterior small intestine (MF1 mice given 5 daily doses of CsA [0–150 mg/kg] following infection); posteriad migration of worms was restricted in a dose-dependent manner. The data presented contrast markedly with the action of the same drug onH. microstomain mice. Thus CsA treatment acts in opposing ways on two closely related parasites in the same host; this possibly reflects the mechanistic antagonism between immunosuppression and anthelmintic activity. This paper reports the first use of a specific T cell-suppressive drug onH. diminutain the mouse, implicating the role of T cells in protective immunity to this parasite.
Modulation of the activity of the internal defence system of the pond snail Lymnaea stagnalis by the avian schistosome Trichobilharzia ocellata
Authors: Amen R. I. , Baggen J. M. C. , Bezemer P. D. , Jong-Brink M. De 
Published: June 2009

SUMMARYEffects of infection with the avian schistosome Trichobilharzia ocellata on the activity of the internal defence system of the intermediate snail host Lymnaea stagnalis were studied, utilizing an in vitro phagocytosis assay for determining haemocyte activity. A distinction was made between plasma- and cell-associated effects. The period immediately after penetration of the parasite into the snail host (1.5–72 h post-exposure (p.e.)) was extensively studied. In addition, several time-points coinciding with the later–successive–stages of parasite development (2, 4, 6, 8 and 10 weeks p.e.) were investigated. Plasma-associated enhancement of defence activity was found between 1.5 and 6 h p.e., followed by plasma-associated suppression between 12 and 72 h p.e. A cell-associated activation was found between 1.5 and 6 h p.e. and also at 8 and 10 weeks p.e. How these effects on the defence system may be related to phenomena observed in infected snails at these time-points is discussed.
Identification and characterization of two repetitive non-variable antigens from African trypanosomes which are recognized early during infection
Authors: Müller N. , Hemphill A. , Imboden M. , Duvallet G. , Dwinger R. H. , Seebeck T. 
Published: June 2009

SUMMARYThe present paper describes two repetitive proteins representing common antigens of African trypanosomes which are non-variant and which are recognized early in infection by the host immune system. These antigens were identified by their ability to immunoreact with bovine serum taken during the early phase of a cyclic trypanosomal infection. Screening of a cDNA library fromT. b. gambiensewith such early infection serum identified a protein which contains a repetitive motif consisting of 68 amino acid repeat units (GM6). Immunofluorescence and immunogold electron microscopy revealed that GM6 is located on fibres which connect the microtubules of the membrane skeleton with the flagellum. A second repetitive antigen detected by this serum is MARP1 (microtubule-associated repetitive protein 1), a protein previously characterized in this laboratory as a high-molecular weight component of the membrane skeleton, which consists of more than 50 tandemly repeated, near-identical 38 amino acid repeat units. Beta-galactosidase fusion products of both proteins demonstrated a strong immunoreactivity with sera fromT. b. bruceiandT. congolense-infected cattle. The result from this preliminary immunological evaluation indicates a high immunodiagnostic sensititivy (90%) of the two recombinant antigens which make them interesting candidates for immunodiagnosis of trypanosomiasis in cattle.
Measurement of Ascaris lumbricoides infection intensity and the dynamics of expulsion following treatment with mebendazole
Authors: Forresteer J. E. , Scott M. E. 
Published: June 2009

SUMMARYIntensity of Ascaris lumbricoides infection was measured in terms of egg counts and worm burden in children 2–10 years of age. The expulsion of A. lumbricoides with a 3-day treatment of mebendazole occurred over 8 days, beginning on the second day of treatment. Ninety-seven percent of the worms were expelled between the second and seventh days. A rapid means of estimating eggs per gram (epg) by the Kato Katz technique correlated well with the method described by Martin & Beaver (1968). In spite of apparent density dependence in egg production, A. lumbricoides egg counts correlated well with worm burdens. It is concluded that, within the context of community surveys, epg is a reasonable means of identifying heavily infected individuals and that epg can be estimated rapidly by a slight modification to the standard Kato Katz technique.
Antibody to carbohydrate and polypeptide epitopes on the surface of schistosomula ofSchistosoma mansoniin Egyptian patients with acute and chronic schistosomiasis
Authors: Omer Ali P. , Mansour M. , Woody J. N. , Smithers S. R. , Simpson A. J. G. 
Published: June 2009

SUMMARY125I-Schistosoma mansonischistosomulum surface antigens were immunoprecipitated with human antibodies from individual Egyptian patients diagnosed as being either acutely or chronically infected withS. mansoni. Both sets of patients were found to have IgG antibodies in their sera capable of immunoprecipitating the majorMr> 200, 38 and 32K antigens. However, the immunoprecipitation of theMr200K antigen was found to constitute a significantly greater proportion of the total precipitate achieved with acute sera than with chronic sera. TheMr38 and 32K antigens were more variably precipitated by the acute sera than the chronic sera but the proportion of the total precipitation that these two antigens constituted was not found to be significantly different between the two sets of sera. Immunoprecipitation with pooled antibodies absorbed with egg and adult worm homogenates which had been treated to remove either carbohydrate or polypeptide epitopes demonstrated that theMr> 200K antigen was the principal target of egg-cross-reactive anti-carbohydrate antibody amongst the antigens detected. TheMr38 and 32K antigens were found to be precipitated by antibodies to protease-sensitive and periodate-insensitive polypeptide epitopes. These results are consistent with egg-cross-reactive anti-carbohydrate IgG antibody making a greater contribution to schistosomulum surface recognition in acute infection than in chronic infection. Indeed the presence of a higher level of egg-cross-reactive and anti-carbohydrate antibody directed against schistosomulum surface epitopes in an acute serum pool than in a chronic serum pool was confirmed by measurement of antibody binding to whole schistosomula.
Aggregation and stability in parasite—host models
Authors: Adler F. R. , Kretzschmar M. 
Published: June 2009

SUMMARYThis paper generalizes the two-dimensional approximation of models of macroparasites on homogeneous populations developed by Anderson & May (1978), focusing on how the dispersion (the variance to mean ratio) of the equilibrium distribution of parasites on hosts is related to the stability of the equilibrium. We show in the approximate system that the equilibrium is stabilized not by aggregation, but by dispersion which increases as a function of the mean. Computer simulations indicate, however, that this analysis fails to capture properly the dynamics of the full system, raising the question of whether any two-dimensional system could produce an adequate approximation. We discuss the relevance of our results to several empirical studies which have examined the relation of dispersion to the mean.