Lachesis muta muta venom: immunological differences compared with Bothropsatrox venom and importance of specific antivenom therapy

Lachesis muta muta and Bothrops an ox snakes are responsible for most accid ents occurring in the Amazon. The clinical features of the accidents are si milar; however, there are still controversies about the efficacy of Bothrop s antivenoms for treating L. nl. muta accidents. In this work, we evaluated the antigenic cross-reactivity between these venoms using polyclonal and m onoclonal antibodies and the efficacy of B. atrox and L. in. muta experimen tal antivenoms in cross-neutralizing the main toxic activities of each veno m. Electrophoretic patterns differed consistently between the species. Howe ver, antigenic cross-reactivity was extensive except for a few bands. Sever al species-specific monoclonal antibodies were obtained by immunization of Balb/c mice with L. m. muta whole venom or B. atrox and L. In. muta specifi c antigens. The monoclonal antibodies specific to L. m. muta recognized dif ferent bands of this venom and the antibodies specific to B. atrox recogniz ed a complex pattern on whole venom by Western blotting. These antibodies a re important tools for developing an immunoassay able to discriminate patie nts bitten by these snakes. The experiments involving cross-neutralization of the main activities of the venoms showed that hemorrhage and blood incoa gulability induced by B. atrox venom were similarly neutralized by both B. atrox and L.,m. muta antivenoms. However, B. atrox antivenom partially neut ralized the hemorrhage and completely failed in neutralizing coagulopathy i nduced by L. ill. muta venom. Therefore, antigenic variation between B. atr ox and L. In. muta venoms does occur and the use of specific antivenom is s uggested For patients bitten by Lachesis snakes. (C) 2000 Elsevier Science Ltd. All rights reserved.