Role of glutathione in the detoxification of ferriprotoporphyrin IX in chloroquine resistant Plasmodium berghei.

The reduction in hemozoin content is a well known feature of chloroquine-resistant Plasmodium berghei. Using NK65-derived lines displaying increasing resistance levels, we observed an inverse relationship between the hemozoin content, and the glutathione (GSH) and glutathione S-transferase (GST) levels. Treatment of highly chloroquine-resistant-infected mice with buthionine sulfoximine (BSO), which has previously been shown to partially reverse this chloroquine resistance, led to a significant increase in hemozoin production.

Schistosoma mansoni: in vitro adhesion of parasite eggs to the vascular endothelium. Subsequent inhibition by a monoclonal antibody directed to a carbohydrate epitope.

Schistosoma mansoni eggs come into direct contact with the vascular endothelium, particularly in the postcapillary venules of the mesenteric tract (oviposition site). We investigated the adhesion of eggs to endothelial cells in a static in vitro assay and in a flow-based in vitro assay. Live S.

High-level chloroquine resistance of Plasmodium berghei is associated with multiple drug resistance and loss of reversal by calcium antagonists.

The chloroquine resistance of Plasmodium falciparum is reversed in vitro by numerous compounds, including calcium antagonists, which could enhance the accumulation of the drug in the parasite food vacuole. However, this mechanism of resistance could be insufficient when the resistance level increases. Using in vitro drug trials on strains of Plasmodium berghei displaying various chloroquine-resistance levels, we confirmed previous results obtained in vivo in the chloroquine-resistant strains of P.

[Immunofluorescence reaction of antibodies directed against the intestinal epithelium of Schistosoma mansoni. VI. Immunolocalization of a carbohydrate epitope at different developmental stages].

In the course of previous works, we described an IgM monoclonal antibody directed to a carbohydrate epitope located on the gut epithelium surface of the Schistosoma mansoni adult worm. We provided evidence that this epitope was present in all stages of the parasite and was particularly abundant in eggs. The current work was performed in order to specify the epitope localisation, at each stage, by immunohistochemical techniques.

Endothelium activation related increase of soluble intercellular adhesion molecule-1 in human schistosomiasis. Lack of correlation with serology.

Soluble intercellular adhesion molecule-1 (sICAM-1) level was measured in sera from 41 patients with Schistosoma mansoni schistosomiasis and compared with the sICAM-1 level in 41 healthy subjects. A significant increase in serum sICAM-1 was observed in patients with schistosomiasis compared with control subjects. As they were inhabitants of the French Antilles, the patients were, however, not settled in a malaria endemic zone, allowing this cause of sICAM-1 enhancement to be eliminated.

[Epidemiology of certain endemic parasitic diseases in the town of Guadalupe (Republic of Sao Tome and Principe). II. Other endemic parasitic diseases].

Stool, blood and urine specimens have been collected from 380 inhabitants of all age groups living in the small town of Guadalupe in May 1992. The seroprevalence of Falciparum malaria (96%), toxoplasmosis (73.3%), have been measured.

[Epidemiology of certain endemic parasitic diseases in the town of Guadalupe (Republic of Sao Tome and Principe) I. Schistosomiasis intercalatum and intestinal worms].

Schistosomiasis intercalatum in known to exist in Saõ Tomé since 1988, (Corachan et al.). It is transmitted by Bulinus forskalii, (Brown et al.

Plasmodium berghei: implication of intracellular glutathione and its related enzyme in chloroquine resistance in vivo.

Glutathione (GSH) plays a critical role in the detoxication and the protection of cells against oxidative stress. In the present study we examined the relationship between the intracellular GSH levels as well as glutathione S-transferase (GST), glutathione reductase (GR), and glutathione peroxidase (GPx) activities and how they relate to Plasmodium berghei resistance to chloroquine. Resistant strains (CQR30 and CQR60) were selected in vivo from a sensitive strain (NK65).

[Study by the immunofluorescence reaction of antibodies directed against antigens of the gut epithelium of Schistosoma mansoni. V. Modulation of granulomatous reaction around the egg under the influence of an IgM monoclonal antibody].

The periovular granulomatous reaction has been reduced in vivo by an IgM monoclonal antibody. The granulomatous reaction has been obtained either in unsensitized, or sensitized as well as immunized mouse. The granulomatous reduction could be explained by a decrease in egg viability, owing to the fact that the monoclonal antibody is lethal against an in vitro miracidium suspension.

[Evaluation of an indirect hemagglutination test for the serodiagnosis of amebiasis].

167 sera have been tested to appreciate the value of an indirect hemagglutination test (Amibiase HAI FUMOUZE) comparatively to an agglutination test of sensibilized particles of latex (Bichro latex Amibe Fumouze BLA) Amibiase HAI test comes out as sensitive and specific for the detection of antibodies in patients suffering from visceral amoebiasis. But some antibodies are also detected in patients with an antecedent of amoebiasis, as it is usually the case with some other techniques. A high positivity of the indirect hemagglutination test, and the concordance between the test HAI and the BLA one are in favour of a visceral amoebiasis.

Detection with a monoclonal antibody of a polysaccharide antigen, excreted in the urine, in the schistosomiasis intercalatum focus of Edea (Cameroon).

The detection in the urine specimens of a sample of the inhabitants of Edea of a polysaccharide antigen characteristic for the genus Schistosoma, with monoclonal antibody by means of the inhibition of a passive haemagglutination test, shows that this technique is very sensitive for measuring prevalence of schistosomiasis due to S. intercalatum. In Edea, looking for eggs in stool specimens gives a low prevalence rate of the disease because of the low parasitic load.

Effect of a mass treatment with praziquantel on the excretion in urine of a polysaccharide antigen used for diagnosis of schistosomiasis due to S. mansoni in Cameroon.

The detection in urine, with a monoclonal antibody, of an excreted polysaccharide antigen characteristic of the genus Schistosoma, allows evaluation of the effect of praziquantel used for mass treatment, in a focus of S. mansoni infection. Inhibition of the passive haemagglutination test, which was used for detecting the polysaccharide antigen in urine, is more sensitive for measuring prevalence than the determination of eggs in stools by means of direct examination and the formalin-ether concentration technique.

[Study of antibodies directed against antigens of the gut epithelium of Schistosoma mansoni using an immunofluorescence reaction. IV. Blocking action on immunity of an IgM monoclonal antibody].

The inhibitory effect on immunity is demonstrated by passive transfer experiments in mice. It can be shown in a secondary infection with Schistosoma mansoni and also in primary infection. The results indicate that blocking activity probably interfers with non specific immunity mechanisms.

Detection with a monoclonal antibody of an antigen, characteristic of the genus Schistosoma, excreted in the urine.

In the host, the antigen excreted by schistosomes in the circulating blood is concentrated in the urine. A mouse monoclonal antibody of the IgM class type lambda, directed against an epitope of the intestinal epithelium of the adult worm, is obtained. The antigen found in the urine of the host as well as the monoclonal antibody has been previously characterized.

[Serodiagnosis of schistosomiasis mansoni using an egg extract semi-purified by precipitation with ammonium sulfate].

Fifty one sera from bilharziosis patients and thirty control sera were examined with a Schistosoma mansoni egg antigen purified by precipitation with ammonium sulphate at 50% saturation. Sensitivity and specificity were good and showed a good correlation with results obtained by MSA1 antigen, but antigen tested is far more easier to prepare than MSA1.

[Immunofluorescent reaction of antibodies directed against antigens from the intestinal epithelium of Schistosoma mansoni. III. Study of the reactivity of monoclonal antibodies].

A monoclonal mouse antibody of IgM class was raised against an epitope of the gut epithelium of the adult worm and was applied to the detection of antigen in parasite infection. The antigen was found in urine from mice and hamsters infected with Schistosoma mansoni; a good correlation between the concentration of antigen and worm burden was observed. The antigen was thermostable, soluble in trichloracetic acid; it was not hydrolysed by proteinase K but it was destroyed by metaperiodate.

[Immunofluorescence test of antibodies directed against antigens of the intestinal epithelium of Schistosoma mansoni. II. In the bilharziasis patient].

Specific IgM antibodies to antigens present in the epithelial cells of the gut of adult S. mansoni were measured in 2 230 persons living in areas of different levels of endemicity. Significant differences were found in the prevalence of IgM antibodies in the infected patients of the compared bilharziasis foci: lower prevalences were found in high endemic foci, involving the possibility of a tolerance phenomenon.

[Detection of antibodies against ovum antigens in Schistosoma mansoni bilharziasis].

Fifty-five sera from bilharziasis patients from West Indies and thirty-five control sera (from normal subjects and patients with hydatidosis and fascioliasis) were examined by ELISA for antibodies reacting with S. mansoni soluble egg antigen MSA1 . MSA1 antigen was prepared according to Pelley and coupled to isothiocyanate substituted plastic discs.

[Immunofluorescent reaction of antibodies against antigens of the intestinal epithelium of Schistosoma mansoni. I--In experimentally infested mice].

The present study was carried out to test with the immunofluorescent antibody test the presence of antibodies directed against the gut epithelium of adult schistosomes in experimental schistosomiasis in mice. Paraffin sections of adult female worms fixed in Rossman's fixative were used and antibodies of the different classes and subclasses could be studied with monospecific conjugates. IgM were the predominant antibodies: they appeared at day 12 after infection, reached a peak value by the 2nd month and remained present at lower levels by the 12th month.

[Anti-elastase of human pancreas: preparation and biological interest].

The present paper deals with the use of a new technique in type II human pancreatic elastase studies based on the use of a reversible immune-adsorbent which provides a unique specificity. According to the type of ligand linked on activated Sepharose, the elastase or its antibody in Rabbit could be obtained, in very pure form, in a one step process. The anti-human pancreatic elastase II, which specifically inhibits the enzyme, may be used in therapy whenever the elastase-inhibitor system becomes unbalanced.

[Effect of muramyldipeptide (MDP) on rat resistance to Schistosoma mansoni].

Partial immunity to Schistosoma mansoni, in the rat, can be obtained by injection of a bilharzian antigen together muramyldipeptide (MDP) in a water in oil emulsion. This immunity is the result of both specific and non specific mechanisms.

[Influence of reintervention by the bacillus of Calmette and Guérin (BCG) on the nonspecific resistance of the mouse to Schistosoma mansoni (author's transl)].

Significant resistance to Schistosoma mansoni appears in mice two weeks after treatment with BCG. The state of nonspecific resistance is considerably increased if the injection of BCG two weeks prior to the infestation test is carried out using mice who have already received BCG. Thus, BCG innoculation in an organism presentized to the bacillus antigens increases immunostimulation.