Efficacy of the bothropic antivenom from Butantan Institute: obtention, characterization and neutralization of serinepeptidases from the venom of Bothrops jararaca

Abstract

The snake bite poisoning represents a public health issue for many countries in the world and in 2009 was recognized by the WHO as a neglected tropical condition. The genus Bothrops is considered the most important one in cases of snake bite poisoning in Brazil and, like other snakes, their venom is a complex mixture of components that act on different targets in the prey / victim. Taking in account that proteolytic enzymes from the classes of serine peptidases and metallopeptidases are the main toxins present in the venom of B. jararaca (about 65% of the composition of the venom), this work will focus on those components. Previous studies have shown that at least two serine peptidases, identified by mass spectrometry and still not yet characterized in the venom of B. jararaca, are not fully neutralized by the antivenom from Butantan Institute, and therefore the causes of these flaws should be investigated in this PhD project. We intend to evaluate by immunochemistry assays the ability of recognition of serine peptidases not neutralized by the commercial antivenom. Also, we intend to evaluate the immunogenicity of these peptidases, obtaining experimental sera specific for these molecules in rabbits as animal models. Thus, we believe that it is essential from the point of view of public health and biotechnology, investigate failures in commercial serum and suggest possible solutions. Another important fact that led us to write this project is purify the enzyme responsible for the chymotrypsin-like degrading activity of angiotensin I shown by our group in previous studies and that was partially blocked by the commercial antivenom. This new enzyme seems to belong to a class of serine peptidases undescribed in snake venoms. Thus, several chromatographic steps will be used to obtain the pure protein in order to characterize it. (AU)