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Revista do Instituto de Medicina Tropical de São Paulo

On-line version ISSN 1678-9946

Rev. Inst. Med. trop. S. Paulo vol.28 no.6 São Paulo Nov./Dec. 1986

http://dx.doi.org/10.1590/S0036-46651986000600003 

ORIGINAL ARTICLES

 

Sensibility of different larval stages of Schistosoma mansoni to the Larvae Disappearing Reaction (LDR) in murine schistosomiasis(1)

 

Sensibilidade de diferentes estadios larvares de Schistosoma mansoni à Reação de Desaparecimento de Larvas (LDR) na esquistossomose murina

 

 

Alan Lane de MeloI; Leógenes Horácio PereiraII; Munir ChamoneIII

IGrupo Interdepartamental de Estudos sobre Esquistossomose e Departamento de Parasitologia, ICB/UFMG
IIDepartamento de Bioquímica-Imunologia, ICB/UFMG

 

 


SUMMARY

The delay produced by drug, in the process of cercaria-schistosomulum transformation, was used to verify the sensibility of different larval stages to the host cell immune responses, in vivo. The peritoneal cavity of mice, a model used for in vivo observations, was choiced for the experiments. As well characterized schistosomules, cercariae and larvae in the process of transformation were coated and arrested by host cells, and could not be recovered by simple saline washings. After 10-2M EDTA saline washings, they were released alive, with good vitality and movements. Thus, different kind of larvae in the process of adaptation of the cercaria to the host are strongly coated by immune cells, but these fail to kill the invading organisms, at least during a few hours after invasion.

Key words: Murine schistosomiasis — S. mansoni; Larval stages — Larvae disappearing reaction.


RESUMO

O retardo, induzido pela oxamniquine, no processo de transformação da cercária-esquistossômulo, foi utilizado, para verificar a sensibilidade de diferentes estádios larvares à resposta celular do hospedero, in vivo. A cavidade peritoneal do camundongo, um modelo utilizado para observações in vivo, foi escolhida para estes experimentos. Esquistossômulos, cercárias e larvas no processo de transformação foram seqüestrados pelas células do hospedeiro, não sendo recuperados através de perfusão da cavidade peritoneal com salina. As larvas somente foram liberadas vivas e com movimentos aptís o uso de 10-2 M de EDTA em salina. Os diferentes estádios larvares, no processo de adaptação ao hospedeiro, são intensamente recobertos por células que, entretanto, não conseguem matar os organismos invasores, pelo menos nas primeiras horas após a invasão.


 

 

Texto completo disponível apenas em PDF.

Full text available only in PDF format.

 

 

REFERENCES

1. CLEGG, J. A. & SMITHERS, S. B. — Death of schistosome cercariae during penetration of the skin. II — Penetration of mammalian skin by Schisosoma mansoni. Parasitology, 58: 111-128, 1968.         [ Links ]

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

3. GORDON, R. M. & GRIFFITHS, R. B. — Observations on the means by which the cercariae to Schistosoma mansoni penetrate mammalian skin together with an account to certain morphological changes observed in the newly penetrated larvae. Ann. trop. Med. Parasti., 45: 227-243, 1951.         [ Links ]

4. KASSIS, A. E.; WARREN, K. S. & MAHMOUD, A. A. F. — Antibody dependent complement mediated killing of schistosomule in peritoneal diffusion chambers in mice. J. Immunol., 123: 1659-1662, 1979.         [ Links ]

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

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7. MELO, A. L.; PEREIRA, L. H. & CHAMONE, M. -The effeet of a previous Schistosoma mansoni infection on schistosomulum recovery from the peritoneal cavity of laboratory mice. Trans. roy. Soc. trop. Med Hyg., 74; 827, 1980.         [ Links ]

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10. 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 ]

11. PEREIRA, L. H.; PELLEGRINO, J. & MELLO, R. T. — Activity ol known antischistosomal agents on early developing forms of S. mansoni. J. Parasit., 61: 249-252, 1975.         [ Links ]

12. SMITHERS, S. R. & TERRY, R .J. — The Immunology of Schistosomiasis. Advanc. Parasit., 7: 41-93, 1969.         [ Links ]

13. SMITHERS, S. R. & TERRY, R. J. — The Immunology of Schistosomiasis. Advanc. Parasit., 14: 399-422, 1976.         [ Links ]

14. SMITHERS, S. R. & GAMMAGE, K. — Recovery of Schistosoma mansoni from the skin, lungs and hepatic portal system of naive mice and mice previously exposed to S. mansoni evidence for two phases of parasite attrition in immune mice. Parasitology, 80: 289-300, 1980.         [ Links ]

15. STIREWALT, M. A. — Schistosoma mansoni: cercaria to schistosomule. Advanc. Parasit., 12: 115-182, 1974.         [ Links ]

 

 

Address for reprints:
Prof. Alan Lane de Melo
GIDE — ICB/UPMG
Caixa Postal 2486, 30000 Belo Horizonte, MG, Brasil

Recebido para publicação em 2/12/1985.

 

 

1 This study was supported by CNPq-Brazil, and by the World Health Organization — Switzerland

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