Nitrothiophenes with schistosomicidal activity

Summary A series of nitrothiophene compounds, with activity against Schistosoma mansoni in mice, is described and shown to be more effective than the corresponding nitrofurans.     

The implantation of sepharose beads in mouse livers as an aid in the study of hepatic schistosomal fibrosis

Summary An experimental model of schistosomal portal fibrosis is described. Sepharose beads the size of schistosome eggs, loaded or not with soluble egg antigen (SEA) fromSchistosoma mansoni, are injected into the coecal vein of C3H/Sn mice and become embolized in the liver. Only SEA-coated beads evoke a granulomatous reaction; this is enhanced by simultaneous priming of the mice with spleen cells fromSchistosoma mansoni-infected syngeneic animals. The fibrosis, which ensues around the beads, is stable and is much more evident after priming. Preliminary collagen tissue immunotyping reveals the presence of collagen deposits of types I and III collagen. Type IV collagen remains unchanged in the portal tracts. The model appears to be well suited for studies of the pathogenesis of portal fibrosis.This work was supported by a contract from INSERM (Action Spéciale No 3).     

Antagonism of heterocyclic sulphonamides to the schistosomicidal effect of lucanthone

Zusammenfassung Heterocyclische Sulfonamide, in äquimolekularer Menge an mitSchistosoma mansoni infizierte Mäuse verabreicht, heben die Hemmung von Lucanthone auf die Entwicklung des Parasiten auf.     

Differences in the sensilla of African and American cercaria of Schistosoma mansoni, the agent of human intestinal bilharziasis]

Schistosoma mansoni parasite of the human intestinal bilharziasis is frequently transmitted in Africa by the Snail Biomphalaria pfeifferi and in America by Biomphalaria glabrata. The comparison between four African strains of cercariae obtained from Biomphalaria pfeifferi and five American strains from Biomphalaria glabrata points out variations in the number and arrangement of the sensory receptors.     

Detection of schistosomiasis in rats using micro blood sampling and immunofluorescence during an epidemiologic study]

For a study of rat parasitism with Schistosoma mansoni in Guadeloupe, we used a technique of microbloodsampling followed by an immunofluorescence test. This method makes it possible to take the blood of the rats, the latter being then marked and set loose. It informs us of the presence of the parasite, the time of infestation, and the rats' movements relative to waterspots.     

Numerical variation of ciliated papillae in the miracidia of different strains of Schistosoma mansoni, the organism producing intestinal bilharzia]

In the miracìdia of 13 strains of Schistosoma mansoni, silver impregnation points out variations in the number of ciliated papillae situated between tiers 2 and 3 of epidermal cells, correlative with the size of the miracidia. These variations are related to the intermediate and definitive hosts. The number of ciliated papillae gives objective information on the degree of adaptation between the parasite and its successive hosts.     

Myofibroblasts in hepatic schistosomal fibrosis

Summary Myofibroblasts were identified in liver portal spaces of patients with Symmers' fibrosis following infection by Schistosoma mansoni.Acknowledgments. This research was supported by a grant from U.E.R. (Human Biology) Claude Bernard University, Lyon (France), and by the Conselho Nacional de Pesquisas (Brazil). Thanks are due to Mrs Pavans de Ceccatty for her skillful technical assistance.     

Chaetotaxic variation of the cercariae of Schistosoma mansoni, the agent of intestinal bilharziasis, correlation with the vertebrate host of the parasite]

The chaetotaxy of the cercariae of human or simian strains of Schistosoma mansoni, a fluke producing the intestinal bilharziasis displays a characteristic difference from that of cercariae of the same parasite adapted to Mouse or wild Rat. Taking into account this differential characteristic, makes it possible to determine the human or murine origin of cercariae released from naturally infected snails during epidemiologic investigations.     

Polyvinylchloride (PVC) particles implantation in mouse liver. A technique for experimental study of schistosome eggs-induced liver pathology.

An injection of suspended PVC particles in the caecal vein of mice induces a foreign-body portal granuloma reaction in the liver. Plastic casts of the portal system, after PVC particles implantation, show modifications in the portal bed and are compared with plastic casts obtained in mice infested by Schistosoma mansoni. This technique can be useful to study the cellular dynamics of the portal granuloma and can be a model for schistosomal eggs induced liver pathology.     

Immune phenomena during experimental schistosomiasis in the rat: role of specific and non specific factors]

Partial immunity to Schistosoma mansoni in the rat can be obtained by injection of a bilharzian antigen together with Freund's complete adjuvant. The results are the same no matter what form of the parasite is used (infecting cercariae or adult). This immunity is the result of both specific and non-specific mechanisms, as is proved by the fact that a lesser but still quite clear degree of resistance to infestation can be obtained by injection of Freund's adjuvant alone.     

Molecular parasitology: progress towards the development of vaccines for malaria, filariasis, and schistosomiasis

Advances in molecular biology have allowed for the identification of potential vaccine candidates against several parasitic diseases. Antigens from various life stages of Plasmodium and Schistosoma species and filarial worms have been cloned, sequenced and tested as vaccines. Results to date in animal models have been promising. Modest levels of protection against experimental human malaria have been obtained using both sporozoite and blood-stage antigens. However, a greater understanding of the mechanisms which lead to immunity against parasites is required before effective vaccines can be developed.     

Production of monoclonal anti-Schistosoma mansoni antibodies. Preliminary study of their biological activities]

Monoclonal antibodies against Schistosoma mansoni have been produced by fusion of splenic lymphocytes from S. mansoni infected Rats and P3-X63-Ag8 BALB/c cells. In vitro and in vivo studies of the biological activities of these antibodies have led to the identification of IgE antibodies with a high reaginic activity and antibodies which in a complement dependent or eosinophil dependent system were shown to have a marked cytotoxicity for schistosomula in vitro. This methodology seems to open new perspectives for the study of antibody function in immunity against parasites as well as for the isolation of the corresponding target antigens.     

Polyvinylchloride (PVC) particles implantation in mouse liver. A technique for experimental study of schistosome eggs-induced liver pathology

Summary An injection of suspended PVC particles in the caecal vein of mice induces a foreign-body portal granuloma reaction in the liver. Plastic casts of the portal system, after PVC particles implantation, show modifications in the portal bed and are compared with plastic casts obtained in mice infested bySchistosoma mansoni. This technique can be useful to study the cellular dynamics of the portal granuloma and can be a model for schistosomal eggs induced liver pathology.This work was supported by an ATP (INSERM) 18.75.41 and a scholarship from the Société d'Hépatologie Expérimentale.     

Comparative evaluation of 7 helminth antigens in the enzyme-linked immunosorbent assay (E.L.I.S.A.).

112 sera from Europeans with parasitologically proven helminthiasis were tested in the enzyme-linked immunosorbent assay (E.L.I.S.A.) against 6 crude extracts of various helminths (2 of adult worms: Dipetalonema viteae, Fasciola hepatica; 3 of eggs: Ascaris suum, Toxocara canis, Schistosoma mansoni; and of Echinococcus granulosus scolices) and against bovine hydatid fluid. Each serum was tested simultaneously at a fixed dilution of 1:160 against all antigens. Extensive cross-reactions were observed, leading to the conclusion that non-purified helminth antigens, even in combination, are of limited value for reliable serodiagnosis in E.L.I.S.A.     

Schistosoma mansoni: a chemoattractive factor released by males and its receptor in females

Chemoattraction between developing (23- to 28-day-old) and adult (10- to 12-week-old) Schistosoma mansoni males and females has been described previously. We report here on in vitro attraction of mature worms to released products of worms of the opposite sex. In the absence of a stimulus worms migrated randomly and did not show any preference in their orientation. Males were not significantly attracted to released products of females. Females exhibited greatest attraction to released products of males, and some attraction to the lipid fraction of released products of males. The aqueous fraction of male-released products slightly repelled females. Prior exposure to released products of males rendered females unresponsive to subsequent exposure, suggesting receptor saturation. These findings have important potential implications for the control of schistosomiasis by intercepting attraction and mating between males and females.     

Comparative evaluation of 7 helminth antigens in the enzyme-linked immunosorbent assay (E.L.I.S.A.)

Summary 112 sera from Europeans with parasitologically proven helminthiasis were tested in the enzyme-linked immunosorbent assay (E.L.I.S.A.) against 6 crude extracts of various helminths (2 of adult worms:Dipetalonema viteae, Fasciola hepatica; 3 of eggs:Ascaris suum, Toxocara canis, Schistosoma mansoni; and ofEchinococcus granulosus scolices) and against bovine hydatid fluid. Each serum was tested simultaneously at a fixed dilution of 1:160 against all antigens. Extensive cross-reactions were observed, leading to the conclusion that non-purified helminth antigens, even in combination, are of limited value for reliable serodiagnosis in E.L.I.S.A.     

Schistosoma mansoni: A chemoattractive factor released by males and its receptor in females

Chemoattraction between developing (23- to 28-day-old) and adult (10- to 12-week-old)Schistosoma mansoni males and females has been described previously. We report here on in vitro attraction of mature worms to released products of worms of the opposite sex. In the absence of a stimulus worms migrated randomly and did not show any preference in their orientation. Males were not significantly attracted to released products of females. Females exhibited greatest attraction to released products of males, and some attraction to the lipid fraction of released products of males. The aqueous fraction of male-released products slightly repelled females. Prior exposure to released products of males rendered females unresponsive to subsequent exposure, suggesting receptor saturation. These findings have important potential implicatons for the control of schistosomiasis by intercepting attraction and mating between males and females.     

Transcriptome profiling of lung schistosomula,in vitro cultured schistosomula and adult Schistosoma japonicum

The schistosomulum is the main target of vaccine-induced protective immunity; however, most studies have utilized schistosomula produced by mechanical transformation of infective larvae followed by in vitro culture rather than larvae isolated directly from the lungs of infected mammals. Using transmission electron microscopy, we demonstrated that there was little difference in the ultrastructure of Schistosoma japonicum schistosomula obtained by the two methods. However, significant differences in gene expression profiles were apparent when we used an oligonucleotide microarray to compare the gene expression profiles of schistosomula obtained in vivo from lung tissue with those maintained in vitro, and with adult worms of S. japonicum. It is likely that host environmental factors, which cannot be reliably reproduced in vitro, do influence the growth, development and overall biology of schistosomes. Thus caution is urged when using in vitro-cultured schistosomes and mechanically transformed/cultured schistosomula in molecular, biochemical and immunological studies.