Freeze-fracture study of immune-induced Schistosoma mansoni membrane alterations. I. Complement-dependent damage in the presence of antisera to host antigenic determinants.
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Animals↗
Biomedical subjects
A Capron
Publications and source records attributed to A Capron.
Purification of a surface-specific soluble antigen from Listeria monocytogenes.
A complex antigenic preparation obtained from Listeria monocytogenes serovariant 4b by freeze-pressing, centrifugation, and gel filtration treatment was studied by crossed immunoelectrophoresis, with the aim of preparing an antigenic fraction that could be used to investigate the serological response to listeric infection. Of 17 immunoprecipitates revealed in the soluble extract, one of three major antigens (designated antigen 2) was shown to be a strong antigen in humans or rabbits infected with L. monocytogenes serovariant 4b. A monospecific antiantigen 2 serum was obtained and used to prepare a serologically homogeneous antigen by immunoadsorption. Antigen 2, most probably located on the bacterial surface, is common to all serovariants of L. monocytogenes and to Listeria grayi and is not shared by the main bacterial species known to have common antigens with L. monocytogenes.
Antibodies, Bacterial↗
Activation of complement by Schistosoma mansoni schistosomula: killing of parasites by the alternative pathway and requirement of IgG for classical pathway activation.
Living Schistosoma mansoni schistosomula incubated with normal chicken, guinea pig, human, and monkey sera were killed after 4 hr contact at 37 degrees C. The following data indicate that this action is dependent on the activation of the alternative complement pathway (AP): a) the inactivity of RB, RD, and zymosan-treated serum against schistosomula; b) the partial activity of RD restored in FD; c) the full effect of the C4-deficient guinea pig, C2-deficient human, and the agammaglobulinemic human sera; d) the consumption of both the AP and FB after the incubation of NHS with schistosomula; e) the detection of C3d breakdown product during the contact of the C2-deficient human serum with these young parasites. Killing by serum was decreased as the immature schistosomes developed and was completely absent against 4-day-old lung schistosomula (LS). In other experiments, it was demonstrated that schistosomula, in the presence of IgG, were able to initiate complement activation also through the classical pathway (CP). However, the CP does not appear to play a role in the schistosomulicidal activity of complement. The in vivo relevance of these observations is considered.
Animals↗
Immunodiagnosis of hydatidosis using monospecific immune serum anti Ag5.
Microdouble diffusion technique using whole hydatid antigen and monospecific antiserum against Echinococcus genus-specific antigen 5 was applied to the diagnosis of human hydatid disease. The use of this simple and economical method may be extended to the specific diagnosis of parasitic diseases.
Animals↗
Complement activation by parasites. A review.
Activation of complement by parasites (living parasites or purified parasite antigens) is involved in several mechanisms of the host parasite relationship. In most of the experiments performed in vitro, complement activation was found to be lethal for the parasites, but sometimes it could be essential for the development of parasitemia. Both classical and alternative complement pathways may be activated by parasites; the classical pathway nearly always requires the involvement of antibodies whereas the alternative pathway is activated directly by products released by the parasites or present in their teguments. Activation of complement, especially via the alternative pathway may also be a prerequisite for cellular adherence to parasites which can then cause their death.
Animals↗
The role of circulating immune complexes in the glomerular disease of experimental hepatosplenic schistosomiasis.
The serological and renal changes were studied simultaneously in 115 mice infected with Schistosoma mansoni. IgG and IgM, but not IgA anti-S. mansoni antibodies were detected in the sera, together with circulating immune complexes containing schistosomal antigen. Glomerular mesangial deposits of IgA, IgM and C3 were observed. Despite the strong correlation observed between the occurrence of the circulating immune complexes containing schistosomal antigen and the glomerular deposits, results concerning the behaviour of IgA suggest that portal hypertension and liver damage have a role in the pathogenesis of glomerular lesions.
Animals↗
In vitro killing of S. mansoni schistosomula by eosinophils from infected rats: role of cytophilic antibodies.
The cytotoxic effect of peritoneal cells from Schistosoma mansoni-infected rats against antibody-opsonized or nonopsonized schistosomula in vitro has been studied during the course of infection. Eosinophil-enriched cell preparations were shown to have a high cytotoxic effect on schistosomula in the absence of antibody. The killer cells were identified as eosinophils. As in the ADCC mechanism previously described, mast cell-eosinophil interaction was required for eosinophil cytotoxicity. Rosette formation using S. mansoni antigen-coated erythrocytes was used to demonstrate the presence of anti-S. mansoni IgG2a antibody at the surface of infected eosinophils. Passive sensitization of normal eosinophils with ultracentrifugation pellets of immune rat serum resulted in a significant cytotoxicity of sensitized eosinophils. A close relationship was found between the cytotoxic activity of infected cells and the ability of the corresponding infected serum to arm normal eosinophils. At certain periods after infection, eosinophils from infected rats were less effective than normal eosinophils on antibody-coated schistosomula. EA- (rat) rosetting assay and blockade experiments with homologous immune complexes have revealed in a kinetic study that the blocking of cytotoxic activity of infected eosinophils was related to heat-stable circulating immune complexes. The possible role of immune complexes either in arming or inhibiting effector cells is suggested.
Animals↗
Serum IgE levels in rats infected with Dipetalonema viteae L3 larvae.
Serum IgE levels were measured by radioimmunoassay in rats infected with various doses of L3 infective stage larvae of Dipetalonema viteae. A high stimulation in total serum IgE levels was found with minute doses as well as with large doses of parasite, and IgE levels remained elevated for several months. No further increase in IgE levels was induced by a secondary infection.
Animals↗
Antigenic make-up of Trypanosoma cruzi culture forms: identification of a specific component.
A comparison of Trypanosoma cruzi water soluble antigens with those of stercorarian and salivarian trypanosomes, and Leishmania using immunoprecipitation in gels and immunoelectrophoresis, with the aid of hyperimmune rabbit serum and heterologous adsorptions showed the following. 1) There is a high complexity of soluble antigens of T. cruzi and T. rangeli. 2) At the intraspecific level our results demonstrated the antigenic stability of T. cruzi when maintained in vitro, and that there was quantitative antigenic consistency of the culture forms of different strains of T. cruzi from diverse geographic and parasite sources. At the interspecific level, the antigenic relationships between T. cruzi and the other Trypanosomatidae were established, as follows: 6/10ths of the antigens are shared by stercorarian species (T. dionisii, T. rangeli); 4/10ths by a salivarian trypanosome (T. brucei); and 3/10ths by Leishmania (L. donovani, L. mexicana). 3) Among the 4/10ths of antigenic components specific to T. cruzi, one component was characterized by its antigenicity and immunogenicity in natural and experimental infections, and in immunization experiments; this component was specific to T. cruzi when compared to the other Trypanosomatidae antigens.
Animals↗
[Immunological changes during the immediate postoperative period (author's transl)].
Postoperative variations in the different parameters of humoral and cellular immunity were studied in 18 adult patients in general surgery. Levels of immunoglobulins G (igG) fell and those of immunoglobulins M (igM) increased significantly. Lymphocytic proliferation under the influence of PHA showed a significant fall. Neither polynuclear function nor total complement activity were modified. Patients in whom the postoperative course was complicated by sepsis differed from the others by a lower activity of the lymphocyte transformation test and by a higher level of igG and igM on the day prior to surgery. In addition, deficiency in the lymphoblastic transformation test increased during the postoperative period, there was a further fall in IgG and IgM increased less in these patients than in those in whom the postoperative course was uncomplicated.
Adult↗
Eosinophil-dependent cytotoxicity in rat schistosomiasis. Involvement of IgG2a antibody and role of mast cells.
Using Schistoma mansoni schistosomula collected in vitro and sensitized with 42-day-infected rat serum, normal rat peritoneal cells enriched in eosinophils were proven to subsequently adhere to and kill the schistosomula within 24 to 48 h. The cell-dependent, heat-stable antibody in infected rat serum reached a peak between 30 and 42 days after infection. Inhibition experiments with aggregated immunoglobulins indicated the role of IgG2a antibody in the adherence of eosinophils to sensitized schistosomula. The immune absorption technique showed that IgG2a antibody was involved in the mechanism of cytotoxicity of effector to target cells, whereas the role of IgE antibody could be excluded. Ultrastructural studies revealed the constant presence of eosinophils and mast cells in contact with schistosomula. The use of purified cell populations showed that the cytotoxic effect of the original cell population was significantly decreased after depletion of mast cells and partially restored after addition of mast cells. These observations, together with those concerning the role of IgE immune complexes in macrophage cytotoxicity, suggest the possible participation of anaphylactic antibodies in immunity to schistosomes in the rat.
Animals↗
Trypanosoma cruzi: location of a specific antigen on the surface of bloodstream trypomastigote and culture epimastigote forms.
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Animals↗
The use of the radioimmunoprecipitation-PEG assay (RIPEGA) to quantify circulating antigens in human and experimental schistosomiasis.
A new procedure, the radioimmunoprecipitation-PEG assay (RIPEGA) is proposed for the quantitation of total circulating schistosome antigens (CSA) and circulating antigen '4' in patients, mice and rats infected with Schistosoma mansoni. This sensitive and reproducible method was performed by incubation of [125I]anti-S. mansoni rabbit antibodies (for the detection of CSA) or [125I]anti-antigen '4' antibodies (to detect antigen '4') with sera. Separation of free from complexed antibodies was achieved by a 7% polyethylene glycol (PEG) precipitation. In human schistosomiasis, both CSA and antigen '4' were detected. A direct relationship was observed between S. mansoni egg output and the incidence of CSA. Moreover, all the patients with more than 500 eggs/g stool showed antigen '4' in serum. Both CSA and antigen '4' were also detected during the course of S. mansoni infection in mice. CSA was increased in two distinct periods after infection; the first between the 50th and the 70th day and the second after the 80th day of infection. The antigen '4' became detectable in infected mice after 45 days of infection. In rat schistosomiasis, only CSA was studied. It was demonstrated in two distinct periods after infection, between the 4th and the 6th week and between the 11th and the 14th week. Because of its sensitivity and its ability to detect and quantify CSA and circulating antigen '4', the RIPEGA is recommended for the clinical studies of schistosomiasis.
Animals↗
[3H]serotonin release: an improved method to measure mast cell degranulation.
A method based on the release of tritium-labelled serotonin by activated mast cells in rodents is described. Mast cells incorporate labelled serotonin selectively and release the label after activation by non-specific stimulators (compound 48/80, polymyxin B sulphate, ATP, bovine chymotrypsin and L-alpha-lysophosphatidylcholine) or anaphylactic antibody and the corresponding antigen. These two types of activation were investigated in comparison with the toluidine blue microscopic rat mast cell degranulation test, and a methodological study of the release of [3H]serotonin is described. The measurement of labelled serotonin release provides a simple and quick assay of mast cell degranulation compared to the time required for the classical rat mast cell degranulation technique and achieves a greater sensitivity.
Animals↗
Purification, immunochemical and biological characterization of malate dehydrogenase of Schistosoma mansoni.
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Animals↗
Dipetalonema viteae in hamsters: effect of antiserum or immunization with parasite extracts on production of microfilariae.
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Animals↗
Dipetalonema viteae infection in hamsters: enhancement and suppression of microfilaraemia.
Mature male Dipetalonema viteae released a substance(s) which caused enhanced microfilaraemia in infected hamsters. In hamsters implanted with female D. viteae, the microfilaraemia of a subsequent infection was suppressed. The microfilaraemia of female worms implanted in hamsters was depressed within 5 days when the animals were given a further infection with infective larvae.
Animals↗
Purification of a specific antigen of Trypanosoma cruzi from culture forms.
A monospecific rabbit antiserum was prepared against a specific component of Tryanosoma cruzi epimastigote culture forms (designated antigen 5). Rabbits were immunized intradermally in 30-50 sites with the zone of agarose gel in which the component 5:anti-5 complex was visualized after two-dimensional immunoelectrophoresis. With this appropriate antiserum and the total epimastigote soluble extracts, the specific component of T. cruzi was purified by immunoadsorption. Purity and specificity controls of thefinal product were carried out by prolonged immunization of rabbits, and then by immunoelectrophoretic and two-dimensional electrophoretic analyses.
Adsorption↗