The lysine residues at positions 54 and 69 were conserved in PLA2s from snake venoms. In addition, Trichostatin A order we observed that the amino acid residues Phe106, Lys110, Asp114 and Trp118 were conserved in the acidic Asp49-PLA2s from the Bothrops genus. However, the epitopes Tyr52–Tyr73 and Phe106–Phe119 were specifically recognized by anti-crotalic horse antivenom and not by anti-bothropic horse antivenom, which suggests that the anticoagulant activity of BthA-I was best neutralized by the anti-crotalic horse antivenom. Toxins with similar biological actions usually present structural similarities, which are reflected in their antigenic cross-reactivity and consequent neutralization by heterologous

antivenom sera. Only a few reports have shown antigenic cross-reactivity between B. jararacussu and C. durissus ssp venoms that specifically focused on the PLA2s from both venoms ( de Roodt et al., 1998, de Roodt et al., 1999, Oshima-Franco et al., 2001, Beghini et al., 2007 and Correa-Netto et al., 2010). One report identified linear B-epitopes in myotoxin II, see more a Lys49-PLA2 from B. asper snake venom, by PepSets™-ELISA

assays using a specifically generated rabbit antitoxin serum and a therapeutic polyvalent Crotalinae horse antivenom ( Lomonte, 2012). Their therapeutic antivenom was generated against a mixture of B. asper, Crotalus simus and Lachesis stenophys snakes venoms, which precluded an analysis of cross-reactivity of antibodies against one venom recognizing epitopes in Resveratrol a different venom, a major aim of this study. Our use of two therapeutic antivenom generated independently against bothropic and crotalic venoms permitted our analysis of cross reactivity. While it was difficult to directly compare results, the differences highlight the need for careful

attention to the sources of venoms and antivenom. The results of our antigenic map also reinforce the need for the application of multiple antivenom sera; only two epitopes were detected specifically by the anti-bothropic horse antivenom in relation to four epitopes to the anti-crotalic horse antivenom. Together, it is proposed that; (1) the improved performance observed with the application of both antivenom sera compared to a single antivenom is a result of synergism from expanded specificity rather than shared antigenic determinants, (2) the therapeutic contributions of the anti-crotalic horse antivenom can be linked to the interaction of its antibodies to important regions of BthTX-II and BthA-I and (3) the anti-bothropic horse antivenom appears to neutralize the sites of BthTX-I that are proposed to be myotoxic. The commercial anti-bothropic horse antivenom produced in Brazil by the Vital Brazil Institute and other institutes is prepared by hyperimmunization of horses with a pool of venoms from B. jararacussu, B. jararaca, Bothrops moojeni, B. alternatus and B. neuwiedi while the anti-crotalic antivenom is produced using only C.