Echis pyramidum (Epy) is a venomous snake belongs to Viperidae family; it causes fetal coagulopathy systemic effects and death. Searching for more effective and safe
antivenom is mandatory for viper
bites treatment.
Proteases are the most lethal components in
viper venom inducing
hemorrhage,
edema and coagulation problems. Thus, the study aims to evaluate the potency of the prepared
antisera and their neutralizing properties against the
biological activities induced by whole Epy
venom individually. Echis pyramidum
metalloprotease enzyme (60 kDa) was purified using size-exclusion followed by
DEAE-ion exchange chromatography. The purified Epy
metalloprotease enzyme (SVMP) was detoxified with 1.5 kGy gamma rays from cobalt60 gamma cell and used for immunization. 1.5 kGy irradiated Epy
metalloprotease (SVMPi) showed less lethal activity (LD50) compared to the corresponding native immunogen. The prepared
antisera boosted against whole Epy
venom (WV), 1.5 kGy irradiated whole Epy
venom (WVi), SVMP and SVMPi were tested for neutralization of lethality and
biological activities induced by Epy
venom. The
antibodies elicited against WVi and SVMPi were 30,000 and 20,000 EU, respectively. The anti-SVMPi serum showed the highest neutralization of lethality (ED50) compared to the other prepared
antisera. In addition, it prolonged the clotting time from 49.0 ± 2.5 to 176.2 ± 1.4 s. Furthermore, it demonstrated a highly neutralizing activity against
edema induction and
hemorrhage of Epy
venom by 66.8% and 94.3%, respectively compared with the other prepared
antisera. These findings would encourage further studies for using gamma irradiated purified fraction(s) from different
snake venoms as safe
antigen(s) to produce more effective
antivenoms.