Partial in vivo protection against Peruvian spider Loxosceles laeta venom by immunization with a multiepitopic protein (rMEPLox)

Loxoscelism is a serious public health problem in Peru, with approximately 2500 accidents reported per year. To envision alternatives to cope with this health problem, the neutralizing humoral immune response against the lethal effects of Peruvian spider Loxosceles laeta venom was evaluated in a mouse model by immunization with a non-toxic multiepitopic protein (rMEPLox). This immunogen contains epitopes from an astacin-like metalloprotease, a hyaluronidase and a sphingomyelinase-D from Loxosceles intermedia and from SMase-I from L. laeta venoms. In vivo protection assays showed that five out of six mice immunized with rMEPLox (after six injections) resisted to 1.4 LD₅₀ of L. laeta venom, whereas only two animals from a control group survived. The present results indicates that this multiepitopic protein can be a promising candidate for anti-loxoscelic antivenom production and experimental vaccination approaches.