Second generation snake antivenomics: Comparing immunoaffinity and immunodepletion protocols

A second generation antivenomics protocol, based on affinity chromatography, was compared with a previously (first generation) immunodepletion protocol using as a proof of principle the pan-African EchiTAb-Plus-ICP® IgG antivenom and the venoms of Echis ocellatus, Bitis arietans, and African spitting cobras. The antivenom showed qualitatively similar immunoreactivity patterns using either antivenomic approach. Quantitative departures were noticed between both methods, which may be ascribed to differences in calculating the relative amounts of the non-recognized venom proteins. The smoother baseline in chromatograms of the affinity column allowed better resolution and more accurate quantification of the antivenomic outcome than the original immunodepletion protocol. Our results indicate that both methods can be used interchangeably to investigate the in vitro immunoreactivity of antivenoms. However, advantages of the second generation antivenomics are the possibility of analyzing F(ab′)2 antivenoms and the reusability of the affinity columns. These features contribute to the generalization, economy and reproducibility of the method.