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Biomedical subjects

D Bout

Publications and source records attributed to D Bout.

At least 55 records · Page 3Linked to original sources
PubMed1991

Amplification of the secretory IgA response to Toxoplasma gondii using cholera toxin.

Our study demonstrates that cholera toxin (CT) markedly enhances the intestinal anti-T. gondii antibody response following oral immunisation of mice with a T. gondii sonicate (TSo) and CT. The antibodies induced were mostly IgA and secretory IgA but a small quantity of IgG was also produced. In contrast, no intestinal anti-T. gondii IgM antibodies were detected. Anti-CT IgA antibodies were also present in intestinal secretions but in much lower quantities than the T. gondii-specific IgA. No anti-CT IgG nor IgM antibodies were detected. Western blot analysis showed that CT induced not only an increase of the intensity of the intestinal IgA antibody response to the 30-kDa band but also induced intestinal IgA antibodies against other major T. gondii proteins (p22, and the 28-kDa antigen) as recognised by specific monoclonal antibodies. The amplification of the anti-T. gondii secretory IgA response by means of an appropriate adjuvant may be one major step leading towards an orally induced immune protection against toxoplasmosis.

Adjuvants, Immunologic↗
PubMed1990

Antibody responses to Toxoplasma gondii in sera, intestinal secretions, and milk from orally infected mice and characterization of target antigens.

Toxoplasma gondii-specific antibody responses in serum, intestinal secretions, and milk were identified with an enzyme-linked immunosorbent assay following a single oral infection of mice with strain 76K cysts of T. gondii. Immunoglobulin A (IgA) production began during week 2 of infection in serum and milk and during week 3 of infection in intestinal secretions and persisted in all three throughout the experiment (17 weeks). IgG but not IgM antibodies were detected in intestinal secretions later in the infection. Serum and milk IgG and IgM production began at the same time after infection as did the IgA response. In Western blotting (immunoblotting), intestinal IgA antibodies were shown to react with antigens comigrating with the T. gondii proteins p22, p23, p30, and p43, the 28-kilodalton antigen, and the 55- and 60-kilodalton rhoptry proteins, as recognized by specific monoclonal antibodies. Milk IgA antibodies reacted with antigens comigrating with p30 and p43. Most of the antigens recognized by IgA antibodies were also detected by IgG antibodies. IgA antibodies from all three biological samples detected the same major T. gondii antigens; thus, there was apparently no specific antibody production unique to one locality.

Administration, Oral↗
PubMed1986

Rat resistance to schistosomiasis: platelet-mediated cytotoxicity induced by C-reactive protein.

In rats infected with the parasite Schistosoma mansoni, the concentration of C-reactive protein in the serum increases after the lung stage of infection and is at its highest at the time of terminal worm rejection. The peak of platelet-mediated cytotoxicity induced by infected serum that has been heated (and is free of immunoglobulin E) as well as the time course for the development of platelet cytotoxic activity in infected rats was found to be correlated with the concentration of C-reactive protein. Rat and human platelets treated with homologous serum obtained during an acute phase of inflammation or with purified C-reactive protein were able to kill the immature forms of the worm in vitro. Platelets treated with C-reactive protein were furthermore capable of conferring significant protection against schistosomiasis in transfer experiments. Collectively these data indicate that a system that includes C-reactive protein and platelets participates in the natural resistance of the rat to schistosomal infection.

Animals↗
PubMed1986

Antischistosomal effect of cyclosporin A: cure and prevention of mouse and rat schistosomiasis mansoni.

C57BL/6 mice infected with Schistosoma mansoni at day 0 and injected with cyclosporin A (CyA) either daily or from day -1 to day 3 were protected against schistosomiasis mansoni as indicated by a decrease in the number of worms recovered from the liver 45 days after infection. CyA treatment also protected rats and strains of mice with known immunity defects (nu/nu, P/N, CBA/N). Protection was evident against both primary and secondary infection in mice infected at day 0, reinfected at day 42, and treated daily with CyA either during the course of the experiment or only from day -1 to day 3, as indicated by the worm burden at day 67. In such an experiment of infection and reinfection, the immature worms were shown to be the target of CyA. Administration of the drug 27, 45, 62, or 100 days before infection confirmed the long-term protective effect of CyA. This drug did not evoke the killing of adult worms in vivo. These data confirm and define the curative and preventive effect of CyA against schistosomiasis mansoni.

Animals↗
PubMed1985

Regulatory role of a tripeptide (TKP) from the second constant domain of immunoglobulin G--I. Inhibition of rat and human macrophage activities.

We have previously shown that peptides released after the cleavage of IgG by parasite proteinases were strong inhibitors of the macrophage effector functions against schistosome larvae. The results presented here demonstrate that a single tripeptide set, Thr-Lys-Pro (TKP), inhibits various macrophage functions and can be considered as an immunologically active peptide. Indeed, not only IgE-dependent cytotoxicity but also beta-glucuronidase release, chemiluminescence and ILI production were reduced when rat macrophages were previously incubated with TKP or some analogues. Moreover, chemotaxis and IgE-specific receptor expression were inhibited in both rat and human macrophages after treatment with TKP, without affecting the cell viability. The substitution or acetylation of Thr diminished or suppressed the inhibitory effect of TKP.

Animals↗
PubMed1984

Filaricidal effects of cyclosporin-A against Dipetalonema viteae in Mastomys natalensis.

Outbred male Mastomys natalensis were injected subcutaneously with 100 infective larvae of Dipetalonema viteae obtained from Ornithodorus tartakovskyi. Groups of five animals were treated with 30 mg/kg of the immunosuppressive drug Cyclosporin-A daily for five days (experimental) or Miglyol 812 (control). One group served as untreated controls. Contrary to expectations, 60% of the animals were completely protected against D. viteae and the remainder were partially protected. The mechanism remains unknown.

Animals↗
PubMed1984

Evaluation of ELISA and RAST using purified antigens for diagnosis of hydatidosis.

Purified Echinococcus granulosus antigens have been used in ELISA and RAST to improve the serodiagnosis of hydatidosis. Results in ELISA confirm the interest of purified antigens for a specific diagnosis and the particular relevance of antigen 5. Antigen B has been shown to be relevant in RAST since the highest correlation was obtained between total IgE and antigen B-specific IgE. Moreover, no false positive were shown as using RAST with antigen B. Such a study has now to be extended at a large scale to appreciate the evolutivity of the disease.

Antigens↗
PubMed1984

[Cellular immunology tests applied to the diagnosis of immune system dysfunctions].

In clinical immunology, improved standardisation and simplification have made skin and laboratory tests more amenable both to routine use and more rigorous interpretation. An individual's immune status can be assessed by the in vivo investigation of delayed hypersensitivity to widely distributed antigens or by techniques such as the mitogen test ot lymphoblast transformation, lymphocyte population and sub-population (e.g. T4, T8...) counts. A more delicate test of phagocytosis is provided by the chemoluminescence test. Investigation of allergic states (immediate hypersensitivity) relies on skin tests and also on laboratory techniques such as the basophil degranulation test.

Blood Bactericidal Activity↗
PubMed1982

The use of an excretory-secretory antigen for an ELISA specific sero-diagnosis of visceral larva migrans.

In sera from patients with visceral larva migrans (VLM) syndrome, enzyme-linked immunospecific assay (ELISA) was used to detect IgG and IgE antibody anti-excretory-secretory antigen (ESA) from the second larval stage of Toxocara canis. The technical conditions of the assay were determined. The specificity of IgG ELISA-ESA (with OD values greater than 0.34) allowed the differentiation of VLM syndrome from ascaris or other human parasite infections.

Antibodies↗
PubMed1982

Helminth functional antigens (with special reference to S. mansoni).

Study of helminth antigens with a special reference to Schistosoma are reviewed, not exhaustively but rather as an overview of trends. These antigens are considered at four levels. Firstly, characterization and utilization of genus, species or stage-specific antigens should improve the efficiency of immunological diagnosis of helminth diseases. Then, some well-characterized antigens are of interest because of their involvement in the modulation of the immune response or in the immunopathological field. Finally, identification of relevant antigens capable of eliciting a protective immune response is a prerequisite to any attempt at immunoprophylaxy of helminthic infections.

Anthelmintics↗
PubMed1981

Trichinella spiralis in rats: in vivo effects of the bile and in vitro action of secretory IgA from bile.

The biliary secretion of rats is diverted from the choledoch duct to the bladder. These rats are resuscitated by sub-cutaneous injections of a salt solution and then infected with Trichinella spiralis larvae. It is shown that the number of adult worms is increased (+ 66%); as is the female larvae production (+ 51%); the females' length is also increased (+ 25%). 40 days after the infection the number of muscular larvae is considerably increased (+ 79%) in comparison with control rats. Secretory IgA (SIgA) from rats bile were tested in vitro on the female production of larvae. This larvae production was more inhibited (59%) by immune SIgA than by control SIgA (25%).

Animals↗
PubMed1980

Detection of Schistosoma mansoni M antigen in circulating immune-complexes and in kidneys of infected hamsters.

Circulating M antigen (CMA) of Schistosoma mansoni was found in the trichloroacetic acid (TCA) soluble fraction of a polyethylene glycol precipitate of serum from infected hamsters. It was also found as a TCA-soluble component in an immunoglobulin-containing fraction eluted from infected hamster kidneys. It was not found in similarly treated control sera nor in the products of acid dissociation of circulating immune complexes (CIC) from infected hamster sera. CMA was not detected in the kidneys of normal hamsters. Precipitating anti-M antigen antibodies were present in one of 10 sera from infected hamsters, but not in the eluates of hamster kidneys. These results indicate that CMA is present in circulating immune complexes in infected hamsters. The presence of CMA in kidneys from the same hamsters suggests a possible role for circulating antigens in immune-complexed form in the aetiology of glomerulonephritis in S. mansoni infection.

Animals↗
PubMed1980

Kinetics of classes and sub-classes of total immunoglobulins and specific antibodies to Schistosoma mansoni during murine infection.

During the course of Schistosoma mansoni murine infection there is a dramatic increase of some immunoglobulins and S. mansoni-specific antibodies. The most substantial response is initiated after 40 days of infection and results in a prolonged increase of total IgG1, IgM and IgA. The maximum increase is respectively 26, 14 and 3-fold the basic immunoglobulin level in control mice. Some anti-S. mansoni classes and sub-classes were studied by an original radio-immunoadsorbent test. Anti-S. mansoni IgG1 and IgM antibodies appear and increase at the same time as that of total IgG1 and IgM. Anti-S. mansoni IgA antibodies appear later (80th day) and correspond to a second peak of total IgA.

Animals↗
PubMed1980

Physicochemical characteristics of Listeria specific antigen 2.

Listeria specific antigen 2 (Ag2) was purified to within 97% of homogeneity, with a high yield, using both gel filtration and polyacrylamide gel electrophoresis. Ag2 is a glycoprotein. Its isoelectric point is about 4.2. As determined by sodium dodecyl sulphate-polyacrylamid gel electrophoresis, its molecular weight in 16710 +/- 450. Ag2 may aggregate easily since it was previously found in gel filtration in a peak corresponding to a molecular weight of 160000. No enzyme activity has been found in Ag2.

Amino Acids↗
PubMed1980

Evaluation of circulating antigens by a sandwich radioimmunoassay, and of antibodies and immune complexes, in Schistosoma mansoni-infected African parturients and their newborn children.

Circulating Schistosoma mansoni soluble antigens (CSA), circulating anti-S. mansoni antibodies (CAb), and immune complexes (CIC) were studied in three groups of African patients living in the same area. The first two groups were composed of 26 S. mansoni-infected mothers and their 26 uninfected newborn children. The third group included 13 men and 10 non-pregnant women who were also infected with S. mansoni. CSA were quantified by using a solid phase sandwich radioimmunoassay, which was shown to be sensitive, reproducible, and S. mansoni-specific. CAb were studied by indirect hemagglutination. CIC evaluations were performed by using the Clq binding test. A high correlation was shown between the CSA levels in sera from infected mothers and from the umbilical cord of their newborn children, indicating that CSA are probably transferred through the placenta. CSA levels in mothers were significantly higher than in the third group, in which no difference was found between men and women. On the other hand, CAb and CIC were significantly higher in the third group than in the group of mothers, indicating that CSA levels may be modulated by the immune response of the host.

Adolescent↗