title: Activation of the complement system and leukocyte recruitment by Tityus serrulatus scorpion venom.
abstract: The scorpion Tityus serrulatus is considered one of the most dangerous species in Brazil. Its venom evokes an inflammatory response, although the exact mechanism of this effect is still unknown. The aim of the present study was to investigate the effect of Tityus serrulatus venom (TsV) on the complement system (CS) and on leukocyte recruitment. Complement consumption by TsV was evaluated using in vitro hemolytic assays, immunoelectrophoresis and two-dimensional immunoelectrophoresis of complement components (factor B and C3). In order to evaluate neutrophil migration induced in normal human serum (NHS) in the presence of TsV, in vitro chemotaxis assays were performed using the Boyden chamber model. In vitro TsV induced a concentration- and time-dependent reduction in hemolytic activity of the classical/lectin and alternative complement pathways, with samples of 43.0 microg and 43.4 microg, respectively, inhibiting 50% of the lytic activity. Alterations in C3 and factor B electrophoretic mobility after incubation of NHS with TsV, were identical to those obtained with zymosan (positive control). Incubation of NHS with TsV induced neutrophil chemotaxis similar to that observed with zymosan-activated serum. Our results show that TsV activates the CS, leading to factor B and C3 cleavage, to reduction of serum lytic activity and generation of complement chemotactic factors. Therefore, CS may play an important role in the inflammatory response observed upon scorpion envenomation.
authors.affiliation: Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto-USP, Av. do Café, s/n, 14040-903, Ribeirão Preto, SP, Brazil.
authors.forename: Daniela Trinca
authors.initials: DT
authors.lastname: Bertazzi
authors.forename: Ana Isabel
authors.initials: AI
authors.lastname: de Assis-Pandochi
authors.forename: Vinicius Luis
authors.initials: VL
authors.lastname: Talhaferro
authors.forename: Ana Elisa
authors.initials: AE
authors.lastname: Caleiro Seixas Azzolini
authors.forename: Luciana Simon
authors.initials: LS
authors.lastname: Pereira Crott
authors.forename: Eliane Candiani
authors.initials: EC
authors.lastname: Arantes
mesh_terms: D000818:Animals; D002634:Chemotaxis, Leukocyte / Q000187:drug effects; D003167:Complement Activation / Q000187:drug effects*; D003176:Complement C3 / Q000378:metabolism; D011415:Complement Factor B / Q000378:metabolism; D015941:Complement Hemolytic Activity Assay; D003170:Complement Pathway, Alternative / Q000187:drug effects; D003171:Complement Pathway, Classical / Q000187:drug effects; D004912:Erythrocytes / Q000187:drug effects; D005260:Female; D006801:Humans; D007123:Immunoelectrophoresis, Two-Dimensional; D066298:In Vitro Techniques; D037102:Lectins; D007962:Leukocytes / Q000187:drug effects*; D008297:Male; D011817:Rabbits; D012604:Scorpion Venoms / Q000494:pharmacology*; D012756:Sheep
chemical_list: D003176:Complement C3; D037102:Lectins; D012604:Scorpion Venoms; D011415:Complement Factor B