Comparison of the efficacy of two monovalent experimental antivenoms for Bothrops asper from Colombia

The antivenom is the only specific therapy for treating snakebite. Our objective was to test the efficacy of two experimental monovalent antivenoms developed with Bothrops asper venom from the Andina (ANDI) ecoregion of Colombia. The project was approved by the ethics committee of the Pontificia Universidad Javeriana, the Institutional Committee for the Use of Laboratory Animals and the Uniagraria Foundation. The lethal dose 50 and effective dose 50 were carried out in mice Balb-c, between 18-20g, of the Comparative Biology Unit (UBC) of the Javeriana University. A 4-month immunization schedule was performed in a creole equine using Bothrops asper ANDI venom. Both antivenoms were manufactured from the same pool of hyperimmune plasma with the Bothrops asper venom from Atlántica (ATL) ecoregion. The whole immunoglobulins IgG antivenom was produced by caprylic acid precipitation, while the F(ab)2 was generated by pepsin digestion and caprylic acid precipitation. Electrophoresis was performed to check the antivenom´s weight. The data was analyzed using the Prisma-statMate combined software, San Diego, CA. The venom potency of Bothrops asper ANDI was 57.5 mcg/mouse, 2.8 +/- 0.3 mg/kg and for Bothrops asper ATL at 45.7 mcg/mouse, for 2.3 +/- 0,2mg/kg. The quantification of total proteins for the whole immunoglobulins was 9.8 +/- 1.2 mg / ml, while for the F(ab)2 it was 11.2 +/- 0.8 mg / ml. The neutralizing capacity was calculated at 1.4 mg/ml for whole immunoglobulins and at 1.75 mg/ml for F(ab)2. We found both antivenoms were efficient to neutralize the venom of Bothrops asper ATL, without statistically significant differences, which is justified by sharing some proteins in their venom, even though they are of different ecoregion, but also suggests that part of the neutralization is by antivenom cross-reactivity.