Busca por novos antígenos para a produção de soro antiescorpiônico: construção de antígenos quiméricos e caracterização de proteases da peçonha de T. serrulatus

Abstract

Accidents caused by scorpion stings are a serious public health problem being considered neglected. Treatment of moderate and serious accidents involves the use of antivenom. To provide an improvement in the quality and production of this serum, many researchers have been studying the use of alternative antigens for the production of anti-scorpion serum. Thus this study aimed to produce a recombinant chimeric protein, based on three toxins present in the Tityus serrulatus venom (TsP) for producing anti-scorpion serum and characterization of novel components of the venom capable of generating neutralizing antibodies. The TsQ3 chimera, composed by Ts1, Ts3 and TsNTxP proteins was used as immunogen. Four groups of rabbits were immunized with combinations of two antigens, TsQ3 TsP. Sera obtained have a mutual recognition capability to both antigens, however, produced with the sera showed neutralization TsQ3 less than the capacity of the serum raised against the TsP. This may be due to the absence of any reference sequences or conformational epitopes of the major toxins. Recently Horta et al. (2014) demonstrated the importance of using hialorunidase on the production of anti-scorpion serum. This information prompted us to study the importance of proteases in the production of neutralizing sera. With the aid of venom gland transcriptome of T. serrulatus was possible to identify 12 sequences related to proteases. We identified 11 proteases belonging to the class of metalloproteases, named Metalloserrulases (TsMS 1-11) and a serine protease named TsSP 1. All TSMS's have signal peptide and propeptide, however it was not found the complete sequence of TsSP 1. It was found that the proteolytic activity of this venom has a preference for sites composed of basic amino acids. Although these enzymes are few studies on scorpion venom, they can have a great potential as a novel target for the production of a more effective anti-scorpion serum.