Equatorial spitting cobra (naja sumatrana) from Malaysia (Negeri Sembilan and Penang), Southern Thailand, and Sumatra: Comparative venom proteomics, immunoreactivity and cross-neutralization by antivenom
Document Type
Article
Publication Date
8-1-2022
Abstract
The Equatorial Spitting Cobra (Naja sumatrana) is a medically important venomous snake species in Southeast Asia. Its wide geographical distribution implies potential intra-specific venom variation, while there is no species-specific antivenom available to treat its envenoming. Applying a protein-decomplexing proteomic approach, the study showed that three-finger toxins (3FTX), followed by phospholipases A(2) (PLA(2)), were the major proteins well-conserved across N. sumatrana venoms of different locales. Variations were noted in the subtypes and relative abundances of venom proteins. Of note, alpha-neurotoxins (belonging to 3FTX) are the least in the Penang specimen (Ns-PG, 5.41% of total venom proteins), compared with geographical specimens from Negeri Sembilan (Ns-NS, 14.84%), southern Thailand (Ns-TH, 16.05%) and Sumatra (Ns-SU, 10.81%). The alpha-neurotoxin abundance, in general, correlates with the venom's lethal potency. The Thai Naja kaouthia Monovalent Antivenom (NkMAV) was found to be immunoreactive toward the N. sumatrana venoms and is capable of cross-neutralizing N. sumatrana venom lethality to varying degrees (potency = 0.49-0.92 mg/mL, interpreted as the amount of venom completely neutralized per milliliter of antivenom). The potency was lowest against NS-SU venom, implying variable antigenicity of its lethal alpha-neurotoxins. Together, the findings suggest the para-specific and geographical utility of NkMAV as treatment for N. sumatrana envenoming in Southeast Asia.
Keywords
Venom variation, Antivenom potency, Naja kaouthia monovalent antivenom (NkMAV), Monocled cobra antivenom, Snakebite envenoming
Divisions
fac_med
Funders
Ministry of Higher Education, Government of Malaysia [FRGS/1/2019/SKK08/UM/02/19]
Publication Title
Toxins
Volume
14
Issue
8
Publisher
MDPI
Publisher Location
ST ALBAN-ANLAGE 66, CH-4052 BASEL, SWITZERLAND