SciELO - Scientific Electronic Library Online

vol.36 issue1Relationship between histoplasmin skin test and Histoplasma capsulatum antibody levels detected by ELISA and immunodiffusion testsOn leishmanial antigen detection in tissue sections of Montenegro's reaction author indexsubject indexarticles search
Home Pagealphabetic serial listing  

Services on Demand




Related links


Revista do Instituto de Medicina Tropical de São Paulo

On-line version ISSN 1678-9946

Rev. Inst. Med. trop. S. Paulo vol.36 no.1 São Paulo Jan./Feb. 1994 



Schistosoma mansoni: the effect of dexamethasone on the cercaria-schistosomulum transformation, in vivo


Schistosoma mansoni: o efeito da dexametasona na transformação da cercaria em esquistossômulo, in vivo



Alan Laue de Melo; Marco Victor Hermeto; Rosilene Siray Bicalho; Antônio Pedro Vargas; Fábio Júnior Oliveira Favaretto; Leógeues Horácio Pereira

Grupo Interdepartamental de Estudos sobre Esquistossomose/Departamento de Parasitologia, Instituto de Ciências Biológicas da Universidade Federal de Minas Gerais. CEP 31270-901 Belo Horizonte, MG, Brasil




Treatment with dexamethasone (DMS) in the early phases of the experimental Schistosoma mansoni infection causes an indirect effect on the cercaria-schistosomulum transformation process. This is observed when naive albino mice are treated with that drug (50 mg/Kg, subcutaneously) and infected intraperitonealy 01 hour later with about 500 S. mansoni cercariae (LE strain). An inhibition in the host cell adhesion to the larvae, with a simultaneous delay in the cercaria-schistosomulum transformation, is observed. This effect is probably due to a blockade of the neutrophil migration to the peritoneal cavity of mice, by an impairment of the release of chemotactic substances. Such delay probably favors the killing of S. mansoni larvae, still in the transformation process, by the vertebrate host defenses, as the complement system.

Keywords: Schistosoma mansoni', Peritoneal cavity; Dexamethasone; Neutrophil; Cercaria; Schistosomulun.


O tratamento com dexametasona (DMS) nas fases iniciais da infecção experimental com S. mansoni leva a um efeito indireto sobre o processo de transformação da cercária em esquistossômulo, quando camundongos isentos de infecção são tratados com esta droga (50 mg/ kg, subcutâneamente) e, 01 hora depois, são infectados intraperitonealmente com cerca de 500 cercárias de S. mansoni (cepa LE). Foi observada uma significativa redução na adesão de células do hospedeiro às larvas, com um atraso simultâneo no processo de transformação das cercárias em esquistossômulos. Este efeito é, provavelmente, devido a um bloqueio inespecifícico da migração neutrofilica para a cavidade peritoneal, através de um bloqueio da liberação de substâncias quimio-táticas. Tal atraso pode permitir a morte das larvas de S. mansoni (ainda em processo de transformação) pelas defesas do hospedeiro vertebrado, como o sistema do complemento.



Full text available only in PDF format.

Texto completo disponível apenas em PDF.




1. ATKINSON, J.P. & FRANK, M.M. - Effects of cortisone therapy on serum complement components. J. Immunol., 111: 1061-1066, 1973.         [ Links ]

2. BLACWELL, G.J.; CARNUCCIO, R.; DI ROSA, M. et al. - Glucocorticoids induce the formation and release of anti-inflammatory and anti-phospholipase proteins into peritoneal cavity of the rat. Brit. J. Pharmacol., 76: 1985, 1982.         [ Links ]

3. BLOCH, E.H. - In vivo microscopy of schistosomiasis. IV. The dynamics of the host-parasite responses to Schistosoma mansoni in the hypodermal tissues as observed in transparent chambers in two susceptible hosts during primary and challenge infections. Amer. J. trop. Med. Hyg., 33: 899-910, 1984.         [ Links ]

4. CLARK, R.A.F.; GALLIN, J.I. & FAUCI, A.S. - Effects of in vivo prednissone on in vitro eosinophil and neutrophil adherence and chemotaxis. Blood, 53: 633, 1979.         [ Links ]

5. COKER, C.M. - Effects of cortisone on immunity to Schistosoma mansoni in mice. Proc. Soc. exp. Biol. (N.Y.), 96: 1-3, 1957.         [ Links ]

6. DAUCHEL, H.; JULEN, N.; LEMERCIER, C. et al. - Expression of complement alternative pathway proteins by endothelial cells. Differential regulation by interleukin 1 and glucocorticoids. Europ. J. Immunol., 20: 1669-1675, 1990.         [ Links ]

7. CUNHA, F.Q. & FERREIRA, S.H. - The release of a neutrophil chemotactic factor from peritoneal macrophages by endotoxin: inhibition by glucocorticoids. Europ. J. Pharmacol., 129: 65-76, 1986.         [ Links ]

8. CUNHA, F.Q.; SOUZA, G.E.P. & FERREIRA, S.H. - Macrophages stimulated with lypopolysacharide release a selective neutrophil chemotactic factor: an in vitro demonstration. Braz. J. med. biol. Res., 19: 775-776, 1986.         [ Links ]

9. DOENHOFF, M. & LONG, E. - Factors affecting the acquisition of resistance against Schistosoma mansoni in the mice. IV. The inability of T-cell deprived mice to re infection, and other in vivo studies on the mechanisms of resistance. Parasitology, 78: 171-183, 1978.         [ Links ]

10. EVELAND, L.K. - Schistosoma mansoni: conversion of cercariae to schistosomula. Exp. Parasit., 32: 261-264, 1972.         [ Links ]

11. GAZZINELI, G.; RAMALHO-PINTO, F.J. & SILVA, W.D. - Schistosoma mansoni: generation of anaphylotoxin by cercarial extracts. Exp. Parasit., 26: 86-91, 1969.         [ Links ]

12. HARRISON, R.A. & DOENHOFF, M.J. - Retarded development of Schistosoma mansoni in immunossupressed mice. Parasitology, 86: 429-438, 1983.         [ Links ]

13. HERMETO, M.V.; BICALHO, R.S.; MELO, A.L. & PEREIRA, L.H. - Kinetics of the pulmonary phase of Schistosoma mansoni in mice treated with dexamethasone. Rev. Inst. Med. trop. S. Paulo, 32: 168-171, 1990.         [ Links ]

14. HERMETO, M.V.; MELO, A.L.; BICALHO, R.S. et al. - Dexamethasone does not reduce the worm burden in mice infected with in vivo obtained schistomules of Schistosoma mansoni. Rev. Inst. Med. trop. S. Paulo, 35: 389-390, 1993.         [ Links ]

15. HIGGS, G.A. & VANE, J.R. - Inhibition of cyclo-oxygenase and lypoxygenase. Brit. med. Bull., 39: 265, 1983.         [ Links ]

16. KAZMIEROWSKI, J.A.; GALLIN, J.L. & REYNOLDS, H.Y. Mechanisms of the inflammatory response in primate lungs. Demonstration and partial characterization of a macrophage-derived chemotactic factor with preferential activity of polymorphonuclear neutrophils. J. clin. Invest., 59: 273, 1977.         [ Links ]

17. KURIHARA, A.; OHUCHI, K. & TSURUFUJI, S. - Reduction by dexamethasone of chemotactic activity in inflammatory exudates. Europ. J. Pharmacol, 101: 11, 1984.         [ Links ]

18. LEWERT, R.M. & MANDLOWITZ, S. - Innate immunity to Schistosoma mansoni relative to state of connective tissue. Ann. N. Y. Acad. Sci., 113: 54-62, 1963.         [ Links ]

19. MELO, A.L.; PEREIRA, L.H. & CORREA, M.C.R. - In vivo cercaria-schistosomulum transformation: inhibitory effect of oxamniquine. Trans roy. Soc. trop. Med. Hyg., 72: 158-159, 1978.         [ Links ]

20. MELO, A.L. & PEREIRA, L.H. - Inhibitory effect of oxamniquine on detachment of the tail of Schistosoma mansoni. J. Parasit., 66: 1067-1068, 1980.         [ Links ]

21. MELO, A.L. & PEREIRA, L.H. - Kinetics of the cercaria-schistosomulum transformation in vivo. Rev. Soc. bras. Med. trop., 18: 17-21, 1985a.         [ Links ]

22. MELO, A.L. & PEREIRA, L.H. - Kinetics of the cercaria-schistosomulum transformation in vivo. 2. The effect of oxamniquine. Rev. Soc. bras. Med. trop., 18: 251-255, 1985b.         [ Links ]

23. MELO, A.L.; MACHADO, C.R.S. & PEREIRA, L.H. - Differences between in vitro and in vivo obtained schistosomules. Rev. Inst. Med. trop. S. Paulo, 32: 84-85, 1990.         [ Links ]

24. MELO, A.L.; MACHADO, C.R.S. & PEREIRA, L.H. - Host cell adhesion to Schistosoma mansoni larvae in the peritoneal cavity of naive mice. Histological and scanning electron-microscopic studies. Rev. Inst. Med. trop. S. Paulo, 35: 17-22, 1993.         [ Links ]

25. MOORE, D.V. & MELENEY, H.E. - Development of Schistosoma mansoni in the peritoneal cavity of mice. J. Parasit., 41: 235-245, 1955.         [ Links ]

26. OSBORN, L. - Leukocyte adhesion to endothelium in inflammation. Cell, 62: 3-6, 1990.         [ Links ]

27. PARRILO, J.E. & FAUCI, A.S. - Mechanisms of glucocorticoid action on immune process. Ann. Rev. Pharmacol. Toxicol., 19: 179-201, 1979.         [ Links ]

28. PEREIRA, L.H.; PELLEGRINO, J.; VALADARES, T.E.; MELLO, R.T. & COELHO, P.M.Z. - A new approach for screening prophylactic agents in schistosomiasis. Rev. Inst. Med. trop. S. Paulo, 16: 123-126, 1974.         [ Links ]

29. SOUZA, G.E.P. & FERREIRA, S.H. - Blockade by antimacrophage serum of the migration of PMN neutrophils into inflamed peritoneal cavity. Agents and Actions, 17: 97-103,1985.         [ Links ]

30. WEINMANN, C.J. & HUNTER, G.W. - Studies on schistosomiasis. XIV. Effects of cortisone upon the Schistosoma mansoni burden in mice. Exp. Parasit., 9: 239-242, 1960.         [ Links ]



Recebido para publicação em 22/12/1992.
Aceito para publicação em 26/11/1993.
This work was supported by CNPq, FAPEMIG, FINEP (Brazil) and Parasitic Diseases Program - W. H. O. (Switzerland).

Creative Commons License All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License