Antigens of Bothrops jararacussu snake venom cross-reacting with specific antibodies against crotoxin, an Asp49 PLA2-containing heterodimeric complex from Crotalus durissus terrificus snake venom, were purified by two steps of immunoaffinity chromatography. The resulting fraction (Bj-F) was shown to be non-toxic (to mice and rabbits) and immunogenic to rabbits. Antibodies raised against Bj-F were able to protect mice against the lethal effect of both B. jararacussu and Crotalus durissus terrificus snake venoms. Then, the procedure developed showed to be useful for the rapid preparation of an antigen able to elicit neutralizing antibodies against the lethal activities of both venoms. Further fractionation of Bj-F revealed the concomitant presence of two major components: BJcuL, a lectin present in B. jararacussu venom, and BthTX-I, a Lys49 PLA2 homolog, besides other molecules in minor amounts. Our data are discussed and raise the point that the presence of unrelated molecules may be taken into account when immuno-based methods are considered for purification purposes. © 2007 Elsevier Ltd. All rights reserved.