Production of monovalent anti-Bothrops asper antivenom: development oí immune response in horses and neutralizing ability

En el Instituto Clodomiro Picado se produjo un suero monovalente contra el veneno de la serpiente Bothrops asper (terciopelo). Durante las primeras etapas del proceso los caballos inmunizados mostraron un título similar en lo que respecta a la neutralización del veneno; sin embargo, uno de ellos mostró un título muy superior en la última fase de la inmunización. El suero monovalente fue más efectivo que el suero polivalente comercial para neutralizar el veneno de B. asper. Por otra parte, el suero monovalente fue menos efectivo que el polivalente para neutralizar las actividades letal y hemorrágica de los venenos de Lachesis muta (cascabel muda) y Crotalus durissus (cascabel). Más aún, el monovalente no neutralizó la actividad desfibrinante de estos dos venenos. Se propone que el suero monovalente anti-B. asper es altamente efectivo en la neutralización del veneno homólogo, en tanto que su empleo en el tratamiento de envenenamientos por L. muta y C. durissus se justifica sólo cuando el suero polivalente no esté disponible. A monovalent antivenom was produced by immunizing two horses with venom of the pit viper Bothrops asper (Ophidia: VipeIidae). Although development of the immune response against four toxic and enzymatic activities of the venom was similar in both horses during the the two thirds of the immunization schedule, antibody response in one of the horses reached much higher levels in the last part of the immunization. Immunoelectrophoretic analysis indicates that there were precipitating antibodies in the sera of these horses during all the stages of immunization. However, immunoprecipitation did not correlate with the ability of sera to neutralize toxic activities of B. asper venom. Monovalent antivenom was more effective than the commercially available polyvalent antivenom in the neutralization of Bothrops asper venom. On the other hand, despite the fact that it neutralizes lethal and hemorrhagic activities of the venoms of Lachesia muta and Crotalus durissus durissus, it was less effective than polyvalent antivenom in these neutralizations. Moreover, it does not neutralize defibrinating activity induced by these two venoms, whereas it neutralizes this effect in the case of B. asper venom. It is proposed that monovalent antivenom may be highly effective in the case of envenomations induced by Bothrops asper venom; its use in treating accidents by L. muta and C. durissus would be indicated only if polyvalent antivenom is not available. Results also demonstrate that it is important to monitor antibody response individually in horses being immunized for antivenom production, due to the conspicuous variability in the response of different animals.