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J. Venom. Anim. Toxins incl. Trop. Dis. Vol.9, No.2, p.490, 2003. Poster - ISSN 1678-9199. |
KINETICS OF TNF-a RELEASE INDUCED BY BAP1, A CLASS PI METALLOPROTEASE ISOLATED FROM Bothrops asper SNAKE VENOM
Fernandes, C.M.(1); Zamuner, S.R.(2), Gutiérrez, J.M.(2), Rucavado, A.(1) Teixeira, C.F.P.(1)
(1)Laboratory of Pharmacology, Butantan Institute, Brazil, (2)Clodomiro Picado Institute, Costa Rica.
Metalloproteases are abundant enzymes in crotalinae and viperinae venoms. They are involved in venom local and systemic toxic effects which include haemorrhage, platelet alterations and myonecrosis. BaP1 is a 24 kDa metalloprotease isolated from Bothrops asper snake venom (Central America). This toxin induces not only weak haemorrhage, but also a moderate myonecrosis and oedema. In the present study we evaluated the effects of BaP1 on isolated peritoneal elicited macrophages (Mfs) analyzing the cell viability and production of tumor necrosis factor (TNF-a). Mfs from Swiss male mice were obtained 96h after intraperitoneal (i.p.) injection of thioglycollate. These cells were incubated (5 to 90min) with BaP1 (6.25 – 25mg/mL) or RPMI(control).Cell viability was assessed by Trypan Blue exclusion test. TNF-awas determined by a standard assay using L929 cell line in co-culture with Mfs. BAP1 induced a marked release of TNF-aat 5 min of incubation with all the concentrations used. However, no release was detected at 30min. A significant release of cytokine was observed only with the highest concentration of BAP1 at 60min. Significant but low concentrations of TNF-awere released from macrophages 90min after incubation with all concentrations of the toxin. The present data demonstrate that BaP1 is not directly toxic to elicited Mfs and is able to induce the release of TNF-aby these cells. This effect appears to be related to the toxin proteolytic activity at the first period and also to induction of TNF-asynthesis at the last period of incubation.
Financial support: FAPESP
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