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.     

Role of Schistosoma mansoni bilharziasis in male hypogonadism]

In tropical and subtropical areas, schistosomiasis may cause anatomic anomalies of the genital organs responsible for permanent or reversible infertility. Furthermore, it has been suggested that this parasitic infection may have adverse consequences on the endocrine system. To specify the effects of schistosomiasis on endocrine function, production of pituitary gonadotropins and testosterone in rats and hamsters experimentally infected with Schistosoma mansoni was studied. Prior to infection, hormone levels were within the normal range for our laboratory in all animals studied. Hormone levels (FSH, LH and testosterone) fell significantly in all experimentally infected animals, as compared with uninfected controls. These data suggest that the inhibitory effect (documented by the fall in all the hormone parameters studied) of Schistosoma mansoni on gonadal function is due to an action at the hypothalamic or pituitary level. The potential role of parasite ecdysteroids in the mechanism of action of schistosomes deserves to be studied.     

Schistosoma mansoni: Analysis of monoclonal antibodies reactive with gut-associated antigens

The analysis of a series of monoclonal antibodies (mAbs) developed in our laboratory against gutassociated antigens ofSchistosoma mansoni is described. It was found that mAbs that recognized epitopes of antigens in the gut and on the eggshell were mainly of the IgM isotype; these epitopes are likely to be carbohydrate in composition. Of a number of mAbs that were reactive with antigens important to the human humoral immune response, 75% appeared to be reactive with the circulating cathodic antigen.     

The occurrence of proteolipid antigens in Schistosoma mansoni

Adult Schistosoma mansoni were shown to synthesize a peptide containing lipid against which an antiserum could be raised in rabbits. The proteolipid purified by silicic acid chromatography was soluble in chloroform/methanol mixtures, it was very hydrophobic and contained fatty acids in its molecule, as well as other unidentified neutral lipids.     

Immunoblot analysis of membrane antigens of Schistosoma mansoni, Schistosoma intercalatum, and Schistosoma haematobium against Schistosoma-infected patient sera

Antigens present in aqueous n-butanolic extracts (BE) of Schistosoma mansoni (Venezuelan JL strain), Schistosoma intercalatum (Cameroon EDEA strain), and Schistosoma haematobium (Yemen strain) adult worm membranes were compared in immunoblot against sera of patients infected with S. mansoni, S. intercalatum, S. haematobium, Schistosoma japonicum, or Schistosoma mekongi looking for similarities (common antigens) and differences (species-specific antigens). About 17 S. mansoni BE polypeptides (M _r ∼8 to >80 kDa) were commonly recognized by S. mansoni-infected patient sera from Venezuela, Senegal, and Ethiopia. S. intercalatum-, S. haematobium-, or S. japonicum-infected sera were almost unreactive with S. mansoni BE. Nonetheless, S. mekongi-infected sera weakly cross-reacted with a ∼10–15-kDa subset of S. mansoni BE. About 72.7% of S. intercalatum-infected patient sera reacted with a ∼19–21-kDa complex in S. intercalatum BE and cross-reacted with a similar complex in S. haematobium BE. Conversely, all S. haematobium-infected patient sera reacted with a ∼19–21-kDa complex in S. haematobium BE and cross-reacted with the ∼19–21-kDa complex in S. intercalatum BE; S. mansoni- and S. japonicum-infected patient sera did not react with S. intercalatum or S. haematobium BE. Results showed the presence of a common membrane antigen between African schistosome species and species-specific antigens in S. mansoni BE that could be useful to discriminate between species and/or to detect Schistosoma infections.     

Developmental bilharziasis caused by Schistosoma mansoni discovered 37 years after infestation

The authors report a case of Mansoni Schistosomiasis whose course in always running thirty-seven years after the first and alone infestation in a fifty-six old man who come back from Madagascar in February 1948 and lives in France since this period eggs of schistosomiasis were living in a biopsy of rectal and sigmoid mucosea. Problem of adult worms longevity and clinical importance of such prolonged inapparent schistosomiasis are discussed.     

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. The antigen was shown to be Schistosoma genus specific. It was found in different developmental stages of the parasite. High levels were detected in egg extracts.     

Schistosoma mansoni anticomplementary antigens (SACA): Detection in schistosomula and adult worms

In previous studies we have shown that schistosomula of Schistosoma mansoni are able to activate complement (C), in the absence of antibodies, by both the classical (CP) and the alternative C pathway (AP). In the present work we have demonstrated that certain factors present in the antigen extract of schistosomula and adult worms also showed an anticomplementary activity. These schistosome anticomplementary antigens (SACA) were found in the low molecular weight fraction (< 35,000 daltons) of the whole extract of adult schistosomes and were able to deplete C through both the CP and the AP.     

Immunochemical characterisation of Schistosoma mansoni glycolipid antigens.

The aim of this study was to investigate the occurrence, distribution and immunochemical properties of antibody-defined carbohydrate epitopes in neutral glycolipid fractions of Schistosoma mansoni eggs, cercariae and adults. The amount of extractable, antigenic, neutral glycolipids was lowest in adult worms, increasing consecutively in cercariae and eggs. The immunoreactivity of the glycolipids resided in the carbohydrate moiety in that it was periodate-sensitive. Serological reactivity, and monosaccharide component analysis, anomeric configuration and methylation-linkage analyses indicated that there were two dominant epitopes, which could be partially defined immunologically. The first epitope was detected on egg, cercarial and adult glycolipids. It was strongly recognised by mouse chronic infection sera and rabbit hyperimmune sera raised against specific egg antigens, and was defined by the monoclonal antibody M2D3H (Bickle QD, Andrews BJ. Characterisation of Schistosoma mansoni monoclonal antibodies which block in-vitro killing: failure to demonstrate blockage of immunity in vivo. Parasite Immunol 1988;10:151-168). M2D3H appeared to have the same epitope specificity as monoclonal antibody 128C3/3 (Weiss J, Magnani JL, Strand M. Identification of Schistosoma mansoni glycolipids that share immunogenic carbohydrate epitopes with glycoproteins. J Immunol. 1986;136:4275-82). The internal epitope was defined structurally by the presence of fucose 3-linked to 3,4-disubstituted N-acetylglucosamine, which was itself partially substituted by a second fucose residue, to yield the determinant -4[Fucalpha1,2Fucalpha3]GlcNAcbeta1-. The second epitope was defined by the anti-LewisX monoclonal antibody 4D1 and was found primarily on cercarial glycolipids. It was chemically characterised as the LewisX epitope of Galbeta1,4[Fucalpha1,3]GlcNAcbeta1- in a terminal position. The removal of fucose greatly diminished the binding of the anti-LewisX and M2D3H monoclonal antibodies, as well as the polyclonal chronic infection sera, to glycolipids of all three life-cycle stages and thus revealed the epitopic importance of fucose.     

Schistosoma mansoni: Detection and characterization of schistosome derived antigens by inhibition enzyme-linked immunosorbent assay (IELISA) utilizing monoclonal antibodies

Monoclonal antibodies were used in an inhibition enzymelinked immunosorbent assay (IELISA) to detect a variety of schistosome derived antigens. Preparations were obtained from various stages ofSchistosoma mansoni and from the eggs ofS. japonicum. Using appropriate titers of monoclonal antibodies it was possible to detect less than 0.01 g/ml of schistosome antigens. The sensitivity of IELISA was dependent upon the type and concentration of the monoclonal antibody used, as well as upon the source of the antigens. Specificity studies showed that some of the monoclonal antibodies recognized species specific antigenic determinants, while others reacted against genus specific antigens. Furthermore, certain antibodies interacted with antigens which were neither genus or species specific. Fractions ofS. mansoni andS. japonicum egg antigen extracts, which have been previously considered to be relatively pure, were compared using certain monoclonal antibodies. The results indicate that these fractions are very heterogenous with regard to the unique antigenic specificities. For example, most antigenic determinants in crude soluble egg antigen are not retained on concanavalin-A lectin affinity columns and major serologic antigens have more than one determinant with different distributions. The expression of these antigenic determinants appears to be a function of both the concentration of the specific antigen and the mode of expression of the moiety within the antigenic matrix.     

Detection of class-specific antibodies against Micropolyspora faeni antigens in farmers'lung

Micropolyspora faeni antigens were used for specific IgA, IgG and IgM determination with an ELISA technique, and for specific IgE antibodies by means of RAST in eighteen patients with farmer's lung, in nineteen farmers with other chest conditions, and in twenty-nine controls. The farmers’lung group had significantly higher IgG antibody levels than the controls, while specific IgA levels were elevated in ten cases. Specific IgE and-except for three cases IgM levels did not differ from the controls. In the group of farmers with other lung diseases, only three had increased levels of specific IgG antibody. The correlation (0. 89) between IgG by ELISA and a complement-fixation test indicated that C activation by M. faeni antigens is mediated by IgG antibodies.     

Immunoaffinity fractionation of Schistosoma mansoni worm antigens using human antibodies and its application for serodiagnosis.

A crude Schistosoma mansoni soluble worm antigen preparation (SWAP) was fractionated using an immunoaffinity column consisting of specific human anti-SWAP antibodies obtained from chronic S. mansoni-infected human sera and bound to CNBr-activated Sepharose 4B. The chromatographic separation resulted in three fractions: the unbound material (FW), and the eluted antigens with glycine-HCl (F1) and glycine-HCl-NaCl (F2). Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) showed that the purified antigens F1 and F2 consisted of several bands when stained with Coomassie blue and silver stain, with molecular weights between 20 X 10(3) and 200 X 10(3). The F1 and F2 fractions in addition to FW and SWAP were used in an enzyme-linked immunosorbent assay (ELISA) to measure antibody levels in sera from schistosomiasis patients. Each individual serum assessed with the purified F2 antigen gave 100% positivity and three to four times higher optical density in comparison to SWAP with only 88% positivity. No detectable cross-reactive antibodies against F2 were found when a limited number of sera from filariasis, fascioliasis and trichinellosis patients were screened. Furthermore, F2 was also used and found to be more sensitive generally in detecting anti-adult worm antibodies than SWAP in recently schistosomiasis-infected persons. Thus, F2 appears to be a highly sensitive and specific reagent for the serodiagnosis of schistosomiasis infection.     

Diagnosis of bilharziasis from Schistosoma mansoni in the early stage: apropos of 77 cases

Schistosoma mansoni infection was diagnosed in 77 patients among 184 men (41.8%) coming from a regiment which had stayed in an endemic area. When it was recognized, this affection had no symptom in 48% of cases. When symptoms were present, they were general or allergic signs, and digestive troubles. Diagnosis, conjectured by hypereosinophilia, was confirmed by discovery of ova in 34 cases, and, in another hand, by positive immunofluorescence in 43 cases without evidence of parasite. This serological test is the best one for diagnosis, at the outset of disease.     

Human immune responses to Schistosoma mansoni vaccine candidate antigens

To determine the naturally occurring immunological responses to the Schistosoma mansoni antigens paramyosin, IrV-5, Sm-23 (MAP-3), and triose phosphate isomerase (MAP-4), a total of 119 subjects from an area of endemicity for schistosomiasis, including "resistant" subjects (n = 17) were evaluated. Specific immunoglobulin G1 (IgG1), IgG2, IgG3, IgG4, and IgA levels for each of the antigens and the cytokine profile in culture supernatants from antigen-stimulated peripheral blood mononuclear cells (PBMC) were determined. Although all the subjects had a high degree of contaminated water exposure, their infection levels were variable (0 to 1,128 eggs/g of stool). There were direct correlations between infection levels and levels of SWAP- and paramyosin-specific IgG1 and IgG4 (P < 0.05). However, an inverse correlation between infection levels and specific IgG2 to IrV-5 (P < 0.01) was observed. The evaluation of the cytokine profile (interleukin 5 [IL-5], IL-10, gamma interferon [IFN-gamma], and tumor necrosis factor alpha) in response to these antigens showed inverse correlations between the degree of infection and IFN-gamma levels in PBMC supernatants stimulated with paramyosin (P < 0.05) and IrV-5 (P < 0.01). Additionally, inverse correlations between the degree of infection and IL-5 levels in MAP-3- and MAP-4-stimulated PBMC supernatants (P < 0.01) were found. Logistic regression analysis was performed to adjust the results of cytokine profile by age. IL-5 production in MAP-3-stimulated PBMC supernatants was associated with lower infection levels (odds ratio = 11.2 [95% confidence interval, 2.7 to 45.8]).     

Protection by phospholipids of Schistosoma mansoni schistosomula against the action of cytotoxic antibodies and complement

Schistosoma mansoni schistosomula cultured in the presence of phospholipids showed a decreased sensitivity to the lethal complement-mediated action of anti-schistosome antibodies. Phosphatidyl choline, sphingomyelin and phosphatidyl ethanolamine had a protective action on the schistosomula transformed in vitro by passage through the skin or by a mechanical procedure. Phosphatidyl choline acted regardless of its fatty acid composition. Phosphatidyl serine and phosphatidic acid did not protect. Thus, it appears that phospholipids can play a role in parasite resistance to immune attack by cytotoxic antibodies and complement, and that this role is specific to certain phospholipid types.     

Detection of Schistosoma mansoni membrane antigens by immunoblot analysis of sera of patients from low-transmission areas

Schistosoma mansoni surface membrane components play a relevant role in the host-parasite interaction, and some are released in vivo as circulating antigens. n-Butanol extraction favors the release of membrane antigens like alkaline phosphatase, which has been shown to be specifically recognized by antibodies from S. mansoni-infected humans and animals. In the present study, components in the n-butanol extract (BE) of the adult S. mansoni worm membrane fraction were separated by one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (1D SDS-PAGE [15%]) and further analyzed by immunoblotting (immunoglobulin G) using defined sera. S. mansoni-infected patient sera, but not sera of uninfected patients or sera obtained from patients infected with other parasite species, specifically and variably recognized up to 20 polypeptides in the molecular mass range of approximately 8 to >80 kDa. There were some differences in the number, intensity, and frequency of recognition of the BE antigens among sera from Venezuelan sites of endemicity with a different status of schistosomiasis transmission. Antigens in the 28- to 24-kDa molecular mass range appeared as immunodominants and were recognized by S. mansoni-positive sera from all the sites, with recognition frequencies varying between 57.5 and 97.5%. Immunoblotting with BE membrane antigens resulted in a highly sensitive (98.1%), specific (96.1.0%), and confirmatory test for the immunodiagnosis of schistosomiasis in low-transmission areas.     

Protection against experimental Schistosoma mansoni schistosomiasis achieved by immunization with schistosomula released products antigens (SRP-A): role of IgE antibodies.

Schistosomula-released products (SRP-A) have been shown to induce preferentially a significant IgE response against Schistosoma mansoni schistosomula when injected into rats, in the absence of adjuvant. The present work provides additional evidence of the in vivo relevance of the anti-SRP-A target antigens. Two strains of rat (Brown Norway and Fischer) were immunized with SRP-A and infected percutaneously. A significant level of protection (up to 83% reduction in worm burden) was observed. Passive transfer experiments carried out with anti-SRP-A or IgE-depleted anti-SRP-A sera suggested the preponderant role of antibodies and particularly of IgE in the protective immunity developed by Fischer rats. Platelets and macrophages recovered from such immunized rats had surface IgE as demonstrated by immunofluorescence analysis with FITC anti-IgE, and have been shown to be directly cytotoxic for schistosomula. The chemiluminescence observed when the macrophages were incubated with anti-IgE suggested the presence of IgE on the surface of these cells.