Horse IgG isotypes and cross-neutralization of two snake antivenoms produced in Brazil and Costa Rica

Horse IgG isotypes and cross-neutralization of two snake antivenoms produce d in Brazil and Costa Rica. Toxicon 000-000. This work compared the specifi city, ELISA titers and IgG subclass content of the polyvalent antivenom (an ti-Bothrops asper, Crotalus durissus durissus and Lachesis muta stenophrys) of Institute Clodomiro Picado (Costa Rica) and the bothropic antivenom (an ti-Bothrops jararaca, B. jararacussu, B. moojeni, B. neuwiedi and B. altern atus) of Institute Butantan (Brazil). The role of IgG(T) and IgGa subclasse s in neutralization of some venom toxic activities and the cross neutraliza tion of the antivenoms against B. jararaca and B. asper venoms were also ev aluated. Both antivenoms were able to recognize B. asper and B. jararaca ve noms by immunoblotting and presented similar antibody titers when assayed b y ELISA. IgG(T) was highest, followed by IgGa, IgGb and IgGc. IgGa and IgG( T) isotypes isolated from both antivenoms by affinity chromatography were t ested for neutralization of lethal, hemorrhagic, coagulant and phospholipas e Az activities of the homologous venoms. In both antivenoms, IgG(T) was th e major isotype responsible for neutralization of all the tested activities . followed by IgGa. These results suggest that Institute Butantan and Insti tute Clodomiro Picado antivenoms have the same IgG profile and their neutra lizing ability is due mostly to the IgG(T) isotype. Also, they neutralize l ethality in mice induced by homologous and heterologous venoms, the bothrop ic antivenom of Institute Butantan being more effective. (C) 1999 Elsevier Science Ltd. All rights reserved.