Preliminary characterization of an adult worm “vomit” preparation of Schistosoma mansoni and its potential use as antigen for diagnosis
- 103 Downloads
Schistosoma mansoni is a parasitic trematode of the portal–mesenteric veins with a closed-end intestine. Adult worms regurgitate their intestinal content after digestion, together with constituents of the lining gut. Some of these molecules circulate in the blood and are antigenic. We obtain a “vomit” preparation and preliminary evaluate its biochemical composition and antigenic capacity. The “vomit” preparation was obtained after changes in temperature and solutions of incubation of adult worms between 4 and 37°C. Supernatant was assayed for protein, carbohydrate concentration and enzymatic activities associated to the intestine and to the worm tegument. The antigenicity of the product was evaluated using Western blot (WB) analysis against sera of experimentally infected mice, before and after drug cure, sera from people infected with S. mansoni and from individuals infected with other parasitoses. More carbohydrate than protein was detected in the preparations. Cysteine proteinase (CP), N-acetyl-β-d-glucosaminidase and alkaline phosphatase activities were detected. The latter enzyme activity is a marker of the tegument, suggesting that in spite of careful conditions used to avoid the presence of tegumental material, manipulation of the worms always resulted in the release of tegumental molecules. Cationic exchange chromatography was useful to separate various components of this “vomit” preparation, particularly enzymes responsible for CP activity. Two highly immunogenic and specific duplets were observed in the WB analysis, 31/32- and 38/40-kDa components, the former probably referring to the intestinal CPs Sm31/Sm32. None of the two duplets disappeared after successful chemotherapy during the time of evaluation in mice or humans.
KeywordsAdult Worm Praziquantel Intestinal Content Schistosoma Mansoni Cysticercosis
This research received financial support from grants obtained from the World Bank–UNDP–Venezuelan Ministry of Health VEN/96/002, FONACIT S1-2650 and CDCH-Universidad de Carabobo 2002-007. Sandra Planchart received a training grant from OPSU–Alma Mater Program, Venezuela. We wish to express our gratitude to M.Sc. Diana Ballen, Lic. Eva Calviño and Lic. César Matos (Instituto Venezolano de Investigaciones Científicas, Caracas) for training in column fractionation, enzymatic assays and for the supply of parasites, Yanett Sáez and Sinecio Rivas (Department of Parasitology, Universidad de Carabobo, Valencia, Venezuela) for help with parasite cycle and experimental infections.
- Chappel CL, Dresden MH (1988) Antibody response to a purified parasite proteinase (SMw 32) in Schistosoma mansoni infected mice. Am J Trop Med Hyg 39:66–73Google Scholar
- De Jonge N, Kremsner PG, Krijger FW, Schommer G, Filie YE, Kornelis D, Van Zeyl RJ, Van Dam GJ, Feldmeier H, Deelder AM (1990) Detection of the schistosome circulating cathodic antigen by enzyme immunoassay using biotinylated monoclonal antibodies. Trans R Soc Trop Med Hyg 84:815–818PubMedCrossRefGoogle Scholar
- El-Sayed L, Ghoneim H, Demian SR, El-Sayed MH, Tawfik NM, Sakr I, Abou-Basha LM, Renganathan A, Klinkert MQ, Abou-Rawash N (1998) Diagnostic significance of Schistosoma mansoni proteins Sm31 and Sm32 in human schistosomiasis in an endemic area in Egypt. Trop Med Int Health 3:721–727PubMedCrossRefGoogle Scholar
- Feldmeier H, Nogueira-Queiroz JA, Peixoto-Queiroz MA, Doehring E, Dessaint JP, De Alencar JE, Dafalla AA, Capron A (1986) Detection and quantification of circulating antigen in schistosomiasis by monoclonal antibody II. The quantification of circulating antigens in human schistosomiasis mansoni and haematobium: relationship to intensity of infection and disease status. Clin Exp Immunol 65:232–243PubMedGoogle Scholar
- Gómez YM, Pereira VRA, Nakasawa M, Montarroyos U, Souza WV, Abath FCG (2002) Antibody isotype responses to egg antigens in humans chronic schistosomiasis mansoni before and after treatment. Mem Inst Oswaldo Cruz 97(Suppl 1):111–112Google Scholar
- Morales GA, Pino de Morales LA (1995) Parasitometría. Universidad de Carabobo, Valencia, VenezuelaGoogle Scholar
- Salas RM, Sánchez IB, Rodríguez R, Aular SM, Loaiza LC, Balzán C, Incani RN (1997) Esquistosomiasis mansoni en el valle de Los Naranjos, Estado Carabobo, un foco de alta transmisión. I. Epidemiología básica. Acta Cient Venez 48(Suppl 1):171Google Scholar