Data/hora: 02/06/2024 17:57:17

Biblioteca(s): 	Embrapa Pantanal.	
Data corrente: 	11/09/1997	
Data da última atualização: 	11/09/1997	
Autoria: 	SILVA, R. A. M. S.; RAMIREZ, L.; DAVILA, A. M. R.; VICTORIO, A. M.; PEREIRA, M. E. B.	
Afiliação: 	EMBRAPA. Centro de Pesquisa Agropecuaria do Pantanal (Corumba, MS); UFMS. Centro Universitario de Corumba. Departamento de Ciencias do Ambiente (Corumba, MS).	
Título: 	An investigation of in vitro phagocytosis of Trypanosoma evansi by rat peritoneal macrophages: increase mediated by parasite-specific antibodies.	
Ano de publicação: 	1996	
Fonte/Imprenta: 	Memorias do Instituto Oswaldo Cruz, Rio de Janeiro, v.91, p.105, 1996. Suplemento.	
Idioma: 	Inglês	
Conteúdo: 	Trypanosoma evansi causes and usually fatal disease in rats, mice, horses and dogs. Phagocytosis and the intracellular killing of pathogens in probaly one of the most important defense system available to an animal. Macrophages (Mo) are central cells in the action and regulation of the immune network. This is in view of their function as phagocytic and antigen-presenting cells, are their release of mediators, expression of surface receptors, and interaction with T and B cells. This experiment was developed to evaluate the influence of parasitic-specific antibody in the phagocytosis by peritoneal Mo of rats. Peritoneal Mo, 1,45 x 10 6 were isolated from Wistar rats pretreated 3 days before single intraperitoneal dose of tioglicolate. The Mo were then precultivated for 24 h. on coverslips in culture flasks. Trypanosomes, 8,7 x  10 6(final concentration) were added to the adherent macrophages and were cocultivated at 37 oC for 5, 15, 30, 45 min. in EAGLE medium (Instituto Adolfo Lutz, SP). The trypanosome/ Mo proportion was 6:1. The phagocytosis test was performed in two groups: group A (Mo treated with normal serum) and B (Mo treated with 200 ul of serum from horse naturally infected by T.evansi). The parasites were not observed attached or phagocytosed by Mo in group A. In group B trypanosomes attached to 51,26% of the Mos within 5 min, 17,20% within 15 min, 46,15% within 30 min, 10,65% within 45 min. The phagocytosis process was observed in 96,63% of the Mos at 5 min, 83,87% at 15 min, 100% at 30 min, and 94,26% at 45 min. We conclude that the absence of phagocytosis in the group A could be explained normal macrophages have some difficulty to uptake the parasites; although some of parasites attach to the Mo, they are not internalized as observed in experiments with T.brucei. The espace from phagocytosis is even improved because of short cell contacts due to permanent movement of the cells concerned. However, in the presence of parasite-specific antibodies (group B), internalization and degradationof the trypanosomes took place. So, according to Shakibaei & Frevert, in the absence of antibodies, bloodstream trypanosomes are protected against phagocytosis by the surface coat. In immune animals the parasites are removed from the bloodsteam by phagocytic cells. The opsonization with specific antibodies or proteolytic removal of the coat result in rapid uptake of the parasites by Mos.	
Thesaurus Nal: 	Trypanosoma evansi.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Pantanal (CPAP)	
Exemplares: 	CPAP - (34845-1) - UPC - AP - -- - AP614.405 -  - 614.405 - DIS