Antivenom Derived from the Ct1a and Ct17 Recombinant Toxins of the Scorpion Centruroides tecomanus

Scorpionism in México is a public health problem caused by stings from the Centruroides scorpion family. The Ct1a and Ct17 toxins from the venom of the Centruroides tecomanus scorpion are the most abundant and toxic for mammals. This study describes the heterologous expression of recombinant proteins from genes encoding these toxins merged with thioredoxin in the vector pET-22b + and expressed in Escherichia coli BL21 (DE3). The yield of Ct1a and Ct17 recombinant toxins was 1.25 mg and 1.737 mg per liter of culture, respectively. These were purified by metal ion affinity chromatography and RP-HPLC and were used for immunization in rabbits, obtaining polyclonal antibodies that confer a positive immune response against the complete venom of Centruroides tecomanus . The serum was tested in vitro and in vivo, obtaining neutralization and protection against the venom. Both toxins were produced recombinantly and fused to the thioredoxin protein; remarkably, the recombinant toxins were excellent immunogens. 300 μl of each immunized rabbit serum was tested in mice, resulting in 50% of the mice protected with each serum, but when the sera were pooled, the protection increased to 83%. This communication reveals the possibility of producing a specific and regional antivenom with polyclonal antibodies that neutralize the complete venom of Centruroides tecomanus . The sequence similarity of Ct1a and Ct17 to Cn2, a toxin that recognizes sodium channels, allowed in silico modeling analysis and a proposal for the different toxicities of Ct1a and Ct17.