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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Bothrops snake venoms and their isolated toxins, an L-amino acid oxidase and a serine protease, modulate human complement system pathways

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Ayres, Lorena Rocha [1] ; Recio, Alex dos Reis [1] ; Burin, Sandra Mara [1] ; Pereira, Juliana Campos [1] ; Martins, Andrea Casella [1] ; Sampaio, Suely Vilela [1] ; de Castro, Fabiola Attie [1] ; Pereira-Crott, Luciana Simon [1]
Total Authors: 8
[1] Univ Sao Paulo, Dept Anal Clin Toxicol & Bromatol, Fac Ciencias Farmaceut Ribeirao Preto, BR-14040903 Ribeirao Preto, SP - Brazil
Total Affiliations: 1
Document type: Journal article
Source: Journal of Venomous Animals and Toxins including Tropical Diseases; v. 21, AUG 13 2015.
Web of Science Citations: 12

Background: Activation of the complement system plays an important role in the regulation of immune and inflammatory reactions, and contributes to inflammatory responses triggered by envenomation provoked by Bothrops snakes. The present study aimed to assess whether Bothrops jararacussu and Bothrops pirajai crude venoms and their isolated toxins, namely serine protease (BjussuSP-I) and L-amino acid oxidase (BpirLAAO-I), modulate human complement system pathways. Methods: Lyophilized venom and toxin samples solubilized in phosphate buffered saline were diluted in appropriate buffers to evaluate their hemolytic activity on the alternative and classical pathways of the complement system. Venom-and toxin-treated normal human serum was added to the erythrocyte suspension, and the kinetic of hemolysis was measured spectrophotometrically at 700 nm. The kinetic 96-well microassay format was used for this purpose. We determined the t(1/2) values (time required to lyse 50 % of target erythrocytes), which were employed to calculate the percentage of inhibition of the hemolytic activity promoted by each sample concentration. To confirm complement system activation, complement-dependent human neutrophil migration was examined using the Boyden chamber model. Results: At the highest concentration tested (120 mu g/mL), B. jararacussu and B. pirajai crude venoms inhibited the hemolytic activity of the classical pathway (65.3 % and 72.4 %, respectively) more strongly than they suppressed the hemolytic activity of the alternative pathway (14.2 and 13.6 %, respectively). BjussuSP-I (20 mu g/mL) did not affect the hemolytic activity of the classical pathway, but slightly decreased the hemolytic activity of the alternative pathway (13.4 %). BpirLAAO-I (50 mu g/mL) inhibited 24.3 and 12.4 % of the hemolytic activity of the classical and alternative pathways, respectively. Normal human serum treated with B. jararacussu and B. pirajai crude venoms induced human neutrophil migration at a level similar to that induced by zymosan-activated normal human serum. Conclusion: Together, the results of the kinetics of hemolysis and the neutrophil chemotaxis assay suggest that pre-activation of the complement system by B. jararacussu and B. pirajai crude venoms consumes complement components and generates the chemotactic factors C3a and C5a. The kinetic microassay described herein is useful to assess the effect of venoms and toxins on the hemolytic activity of the complement system. (AU)

FAPESP's process: 11/23236-4 - Native and recombinant animal toxins: functional, structural and molecular analysis
Grantee:Suely Vilela
Support type: Research Projects - Thematic Grants