Faisal Tasnim, Tan Kae Yi, Tan Nget Hong, Sim Si Mui, Gnanathasan Christeine Ariaranee, Tan Choo Hock
Department of Pharmacology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
Department of Molecular Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
J Venom Anim Toxins Incl Trop Dis. 2021 Apr 30;27:e20200177. doi: 10.1590/1678-9199-JVATITD-2020-0177.
The western Russell's viper () is widely distributed in South Asia, and geographical venom variation is anticipated among distant populations. Antivenoms used for Russell's viper envenomation are, however, raised typically against snakes from Southern India. The present study investigated and compared the venom proteomes of from Sri Lanka (DrSL) and India (DrI), the immunorecognition of Indian VINS Polyvalent Antivenom (VPAV) and its efficacy in neutralizing the venom toxicity.
The venoms of DrSL and DrI were decomplexed with C high-performance liquid chromatography and SDS-polyacrylamide gel electrophoresis under reducing conditions. The proteins fractionated were identified through nano-ESI-liquid chromatography-tandem mass spectrometry (LCMS/MS). The immunological studies were conducted with enzyme-linked immunosorbent assay. The neutralization of the venom procoagulant effect was evaluated in citrated human plasma. The neutralization of the venom lethality was assessed in mice adopting the WHO protocol.
DrSL and DrI venom proteomes showed comparable major protein families, with phospholipases A (PLA) being the most abundant (> 60% of total venom proteins) and diverse (six protein forms identified). Both venoms were highly procoagulant and lethal (intravenous median lethal dose in mice, LD = 0.24 and 0.32 µg/g, for DrSL and DrI, respectively), while lacking hemorrhagic and anticoagulant activities. VPAV was immunoreactive toward DrSL and DrI venoms, indicating conserved protein antigenicity in the venoms. The high molecular weight venom proteins were, however, more effectively immunorecognized than small ones. VPAV was able to neutralize the coagulopathic and lethal effects of the venoms moderately.
Considering that a large amount of venom can be injected by Russell's viper during envenomation, the potency of antivenom can be further improved for optimal neutralization and effective treatment. Region-specific venoms and key toxins may be incorporated into the immunization procedure during antivenom production.
西方锯鳞蝰广泛分布于南亚，预计不同地区的种群之间存在毒液差异。然而，用于锯鳞蝰蛇咬伤的抗蛇毒血清通常是针对印度南部的蛇生产的。本研究调查并比较了来自斯里兰卡（DrSL）和印度（DrI）的锯鳞蝰蛇毒液蛋白质组、印度VINS多价抗蛇毒血清（VPAV）的免疫识别情况及其中和毒液毒性的效果。
采用C高效液相色谱法和还原条件下的SDS聚丙烯酰胺凝胶电泳对DrSL和DrI的毒液进行解聚。通过纳升电喷雾液相色谱-串联质谱（LCMS/MS）鉴定分离出的蛋白质。采用酶联免疫吸附测定法进行免疫学研究。在枸橼酸化人血浆中评估毒液促凝作用的中和情况。按照世界卫生组织的方案在小鼠中评估毒液致死性的中和情况。
DrSL和DrI的毒液蛋白质组显示出相当的主要蛋白质家族，其中磷脂酶A（PLA）最为丰富（占总毒液蛋白的60%以上）且种类多样（鉴定出六种蛋白质形式）。两种毒液都具有高度促凝性和致死性（小鼠静脉注射半数致死剂量，DrSL和DrI分别为0.24和0.32 µg/g），但缺乏出血和抗凝活性。VPAV对DrSL和DrI的毒液具有免疫反应性，表明毒液中蛋白质抗原性保守。然而，高分子量毒液蛋白比小分子量的更易被免疫识别。VPAV能够适度中和毒液的凝血病变和致死作用。
考虑到锯鳞蝰蛇在咬伤时可注入大量毒液，抗蛇毒血清的效力可进一步提高以实现最佳中和及有效治疗。在抗蛇毒血清生产过程中，可将区域特异性毒液和关键毒素纳入免疫程序。
