Mansoni Soluble Egg Antigen Research Articles

Evaluation of cellular immune response during chronic schistosomiasis in humans by the leukocyte aggregation test and the leukocyte migration inhibition test.

Cellular immune response was evaluated in 31 patients with chronic Schistosoma haematobium and Schistosoma mansoni infections and in 15 healthy normal persons by using S. mansoni soluble worm and egg antigens. Although the leukocyte migration inhibition test demonstrated false-positive reactions, the specificity of the leukocyte aggregation test was confirmed by the negativity of all of the controls. Among the patients, only 10% were positive for the leukocyte aggregation test. This low cellular reactivity was in contrast to markedly elevated specific humoral response determined by an enzyme-linked immunosorbent assay for immunoglobulin G and paper allergosorbent test for immunoglobulin E with soluble worm antigen. These results confirm that the cellular immune reactivity to schistosome antigen as demonstrated by the leukocyte aggregation test is either minimal or absent in chronically infected patients.

Immunodiagnosis of infection with Schistosoma haematobium and S. mansoni in man.

We utilized the circumoval precipitin (COP) test, Ouchterlony immunodiffusion, and the enzyme-linked immunosorbent assay (ELISA) for the serodiagnosis of human infection with Schistosoma mansoni or S. haematobium, or with both species of schistosome. Only the COP test correctly identified all of those with schistosome infection, although differentiation as to schistosome species was impossible. Circumoval precipitates around S. haematobium eggs from human urine were more numerous and larger than those around S. mansoni eggs obtained from mouse livers. Ouchterlony immunodiffusion with S. mansoni or S. haematobium worm extract failed to diagnose correctly approximately one of every five infected individuals. Mean absorption values of the S. mansoni soluble egg antigen (SEA) used in the ELISA were similar in serum samples from persons infected with either or both species of blood flukes. This suggests that S. mansoni SEA is not species-specific. The ELISA correctly identified, however, 30 of 32 infected individuals, indicating high sensitivity.

Antibody responses in murine schistosomiasis and fascioliasis.

Antibody responses in mice with a primary infection of either Schistosoma mansoni or Fasciola hepatica were studied, using antigen preparations from both species. S. mansoni adult worm extracts (Ouchterlony, indrect hemagglutination) detected schistosomiasis in mice by 5-6 weeks, but did not detect fascioliasis through 12 weeks of infection. S. mansoni soluble egg antigen (Ouchterlony, enzyme-linked immunosorbent assay--ELISA) reacted with the sera of mice infected with S. mansoni by 6-7 weeks of infection; only ELISA reacted with the sera of mice infected with F. hepatica (by 3 weeks of infection). The circumoval precipitin test was specific only for mice infected with S. mansoni, being positive by the 9th week of infection. F. hepatica adult worm extract precipitated (Ouchterlony) the sera of mice with schistosomiasis (7 weeks) and fascioliasis (2 weeks).

An Electrophoretic Analysis of Schistosoma mansoni Soluble Egg Antigen Preparation

Schistosoma mansoni soluble egg antigen (SEA) has been examined electrophoretically. Sodium dodecyl sulfate (SDS) electrophoresis of SEA reveals an extremely heterogeneous protein composition. At least 18-20 distinct bands stain with Coomassie blue and at least 6 bands stain with periodic acid Schiff (PAS). Four of the PAS-positive bands stain only faintly with Coomassie blue. The estimated molecular weight range for these proteins is between 16,000 and 200,000 daltons. An acid soluble fraction was isolated from SEA which contained 5 of the 6 glycoproteins. An immunoelectrophoretic analysis of SEA reveals at least 5 distinct precipitin arcs when developed with serum from mice infected with S. mansoni for 16 weeks.

Schistoma Mansoni Soluble Egg Antigens: Determination of the Stage and Species Specificity of their Serologic Reactivity by Radioimmunoassay

Three highly purified Schistosoma mansoni egg antigens reactivity with sera from mice with chronic schistosomiasis mansoni (major serologic antigens-MSA1, MSA2, and MSA3) were utilized in radioimmunoassays for determining their stage and species specificity. Inhibition studies revealed that MSA1 was completely stage specific, since its binding to S. mansoni chronic infection serum (CIS) could not be inhibited either with cercarial or adult worm antigen. MAS2 and MSA3 were specific with regard to adult worm antigen but their binding to CIS was slightly inhibited by cercarial antigen. Immature eggs in comparison with mature eggs contained only negligible amounts of MSA1 whereas MSA2 and MSA3 were present in large quantities. Fluid from eggs hatched in spring water (hatch fluid-HF) contained considerable amounts of MSA1 as well as MSA2 and MSA3. With regard to species specificity, MSA1 essentially did not cross-react with crude soluble egg antigen (SEA) from Schistosoma japonicum and Schistosoma haematobium whereas MSA2 and MSA3 showed partial cross-reactivity. Antibody dilution studies with sera from animals and humans infected with heterologous schistosome species (i.e., S. japonicum and S. haematobium) indirectly confirmed the high degree of species specificity of MSA1. The degree of serologic specificity of MSA1 as demonstrated in this study parallels that of the sensitizing activity of S. mansoni eggs and SEA for granuloma formation, as demonstrated in previous investigations. This study, therefore, indicates that MSA1 may be a major immunopathologically active egg antigen. In addition, the high degree of species specificity of MSA1 suggests its use in the serodiagnosis of schistosomiasis mansoni.

Systemic cellular hypersensitivity induced by an intestinally absorbed antigen.

Neonatal mice given intact living Schistosoma mansoni eggs or soluble schistosome egg antigens intragastrically developed systemic cellular hypersensitivity as shown by markedly accelerated, augmented granulomatous inflammation around S. mansoni eggs subsequently injected intravenously into the pulmonary microvasculature. To achieve partial sensitization in adult mice schistosome eggs had to be administered intragastrically with bicarbonate; full sensitization occurred when the eggs were injected intraduodenally. These data indicate that under appropriate conditions intestinal administration of antigen can result in systemic cellular immune sensitization.