Immunological cross-reactivity and neutralization of the principal toxins of Naja sumatrana and related cobra venoms by a Thai polyvalent antivenom (Neuro Polyvalent Snake Antivenom)

Revisiting Notechis scutatus venom: on shotgun proteomics and neutralization by the “bivalent” Sea Snake Antivenom

“…By incorporating N. scutatus venom in the immunogen, the neutralization of H. schistosus venom by SSAV is likely improved with the additional antibody titer raised against its myotoxic, basic PLA 2 s; however, the overall potency of the antivenom appears to remain limited by the weak neutralization of short neurotoxins which are present in a very large amount in sea snake venom [15]. This is in agreement with recent reports on the consistently weak neutralization of antivenoms against short neurotoxins isolated from Asiatic cobra venoms (Naja naja, Naja kaouthia and Naja sputatrix) [37][38][39]. On the other hand, the neutralization of N. scutatus venom is attributable primarily to SSAV neutralizing the abundant PLA 2 s, and enhanced by the additional anti-titers against the coagulant enzymes and alpha-neurotoxins.…”

“…By examining the venomics, a remarkable difference is noted between the proteomes of the two elapid venoms on their respective major components: H. schistosus venom comprises mainly neurotoxins (short NTX, 55%; long NTX, 15%) and a moderate amount of basic phospholipases A 2 (20%), while N. scutatus contains mainly phospholipases A 2 (75%) and a smaller fraction of hemotoxic serine proteases (6%) and alpha-neurotoxins (short and long NTX, 6%) as its lethal principles. Previous studies have established that the immunoreactivity of low molecular mass neurotoxins (especially for the short NTX) is low in comparison to intermediate or high molecular mass toxins such as PLA 2 , where antivenom neutralization potency for the two toxins could differ as much as 10-fold [15,37]. By incorporating N. scutatus venom in the immunogen, the neutralization of H. schistosus venom by SSAV is likely improved with the additional antibody titer raised against its myotoxic, basic PLA 2 s; however, the overall potency of the antivenom appears to remain limited by the weak neutralization of short neurotoxins which are present in a very large amount in sea snake venom [15].…”

Venom and Purified Toxins of the Spectacled Cobra (Naja naja) from Pakistan: Insights into Toxicity and Antivenom Neutralization

“…18 The findings are consistent with previous studies that revealed weak neutralization capacity of antivenoms toward SNTXs. 19,25 The findings also reflect the difficulty in raising immunoglobulins with sufficiently good reactivity toward SNTXs of elapid species. This could be due to the small molecular size and short peptide sequence of SNTX that limit its immunogenicity in host animals.…”

“…32 The IV LD 50 values of the two NTX subtypes are in agreement with findings for other elapid species. 19,25 Indeed, these are highly potent toxins that are responsible for the rapid onset of neuromuscular paralysis and death in most elapid envenomations, via the blockade of postsynaptic nicotinic cholinergic receptors. 33 Neutralization of these toxins is therefore essential to halt or reverse the venom-induced neurotoxicity.…”

“…2,18 This is particularly relevant in the case of cobra for two obvious reasons: first, cobra distributes widely in many parts of Pakistan and adapts well to human settlements, constituting a common cause of bites in the country; second, antivenom neutralization potency against cobra venom has been reported to be low, ostensibly due to the poor immunogenicity of small polypeptide toxins in the venom. 19 In view of these, this study was conducted to investigate the immunoneutralization profile of the Pakistani N. naja venom, using different cobra antivenoms available in the region. The principal toxins of the venom were also purified and tested for toxin-specific antivenom neutralization.…”