Evaluating the Immunological cross-reactivity of Indian polyvalent antivenoms towards the venom of Hypnale hypnale (hump-nosed pit viper) from the Western Ghats

(hump-nosed pit viper) is a venomous pit viper species found in the Western Ghats of India and Sri Lanka. Due to the severe life-threatening envenomation effects induced by its venom components, has been classified under ‘category 1’ of medically important snake species by the World Health Organization. Since there are no specific antivenoms available to combat its envenomation in India, the only option available is to administer Indian polyvalent antivenoms. However, the cross-neutralization potential of the commercially available polyvalent antivenoms on Indian venom has not been explored so far. In the current study, in vitro immunological cross-reactivity of venom towards various Indian polyvalent antivenoms were assessed using end point titration ELISA and Western blotting. A three to four-fold increase in EC values were obtained for venom towards all the antivenoms tested. Observation of minimal binding specificities towards low and high molecular mass venom proteins are suggestive of the fact that commercially available polyvalent antivenoms failed to detect and bind to the antigenic epitopes of considerable number of proteins present in venom. This highlights the importance of including venom in the immunization mixture while raising antivenoms.