Analysis of Tegumental Surface Proteins of Schistosoma mansoni Primary Sporocysts

• Published in: The Journal of parasitology 1987-08, Vol.73 (4), p.778-786
• Main Authors: BOSWELL, C. A, YOSHINO, T. P, DUNN, T. S
• Format: Article
• Language: English
• Subjects: Animals; Antibodies; Antibodies, Monoclonal; Antigens; Antigens, Helminth - analysis; Antigens, Surface - analysis; Autoradiography; Biological and medical sciences; Diseases caused by trematodes; Electrophoresis, Polyacrylamide Gel; Epitopes; Gels; Helminthic diseases; Hemocytes; Immunology; Infectious diseases; Medical sciences; Membrane proteins; Molecular Weight; Parasite hosts; Parasites; Parasitic diseases; Parasitology; Periodic Acid - pharmacology; Proteins - analysis; Proteins - immunology; Reactivity; Schistosoma mansoni - analysis; Schistosoma mansoni - immunology; Schistosomiases; Tropical medicine
• ISSN: 0022-3395; 1937-2345
• DOI: 10.2307/3282413

Axenically transformed primary sporocysts of Schistosoma mansoni (NMRI strain) were labeled with125I in an effort to identify sporocyst proteins exposed at the tegumental surface. Using the125I activating reagent, 1,3,4,6-tetrachloro-3α,6α-diphe nylglycoluril, in conjunction with SDS-PAGE and autoradiography, up to 12 bands were radiolabeled out of 60 components visualized by silver staining. Labeled proteins ranged in apparent Mrfrom > 200 to < 12 kDa. Pronase treatment of living sporocysts after radioiodination removed all labeled material, suggesting that only surface proteins were being iodinated. Western blot analysis employing 5 monoclonal antibodies (MAB's) to sporocyst surface antigens revealed a wide range of reactivities which produced banding patterns closely reflecting autoradiograms of identical samples. The concomitant removal by Pronase of immunoreactive and radiolabeled surface proteins with identical Mrin the range of 90-130 kDa suggests that epitopes recognized by these antibodies are associated with these higher molecular weight surface proteins. However, although Pronase removes all labeled surface proteins, substantial nonradiolabeled, immunoreactive material with Mr< 90 kDa still remains on enzyme-treated parasites. This indicates that MAB-reactive epitopes, in addition to their occurrence with surface proteins, are also associated with either unlabeled, protease-resistant surface components or internal antigens. The immunohistochemical localization of antibody-reactive material in gland-like structures within sporocysts supports an internal source for nonradiolabeled, immunoreactive components. Finally, the periodate sensitivity of the epitopes recognized by all tested MAB's suggests that carbohydrate moieties may represent a common and extremely immunogenic constituent of the sporocyst surface. Diversity in surface carbohydrate composition may be of importance in regulating sporocyst-hemocyte interactions within the molluscan host.