A comparative study of venomics of Naja naja from India and Sri Lanka, clinical manifestations and antivenomics of an Indian polyspecific antivenom

Liew

et al. 2016

Sci Rep

Serum Anti Ular Bisa (SABU) is the only snake antivenom produced locally in Indonesia; however, its effectiveness has not been rigorously evaluated. This study aimed to assess the protein composition and neutralization efficacy of SABU. SDS polyacrylamide gel electrophoresis, size-exclusion liquid chromatography and shotgun proteomics revealed that SABU consists of F(ab’)2 but a significant amount of dimers, protein aggregates and contaminant albumins. SABU moderately neutralized Calloselasma rhodostoma venom (potency of 12.7 mg venom neutralized per ml antivenom, or 121.8 mg venom per g antivenom protein) and Bungarus fasciatus venom (0.9 mg/ml; 8.5 mg/g) but it was weak against the venoms of Naja sputatrix (0.3 mg/ml; 2.9 mg/g), Naja sumatrana (0.2 mg/ml; 1.8 mg/g) and Bungarus candidus (0.1 mg/ml; 1.0 mg/g). In comparison, NPAV, the Thai Neuro Polyvalent Antivenom, outperformed SABU with greater potencies against the venoms of N. sputatrix (0.6 mg/ml; 8.3 mg/g), N. sumatrana (0.5 mg/ml; 7.1 mg/g) and B. candidus (1.7 mg/ml; 23.2 mg/g). The inferior efficacy of SABU implies that a large antivenom dose is required clinically for effective treatment. Besides, the antivenom contains numerous impurities e.g., albumins that greatly increase the risk of hypersensitivity. Together, the findings indicate that the production of SABU warrants further improvement.

Section: Discussionsupporting

confidence: 69%

Assessing SABU (Serum Anti Bisa Ular), the sole Indonesian antivenom: A proteomic analysis and neutralization efficacy study

Liew

et al. 2016

Sci Rep

“…Thus there is convergence between the two groups in upright hooding displays being associated with defensive cytotoxic function, and as they have evolved the function independently the underlying chemical mechanisms are not homologous. Hemachatus + Naja venoms have a high concentration of the cytotoxic 3FTx unique to this clade [36,37,38,39,40,41,42,43,44,45]. Similarly O. hannah venoms have the highest concentration of L-amino acid oxidase of any snake venom and also the most derived forms of venom L-amino acid oxidase [23,46,47,48,49,50,51].…”

Section: Resultsmentioning

confidence: 99%

How the Cobra Got Its Flesh-Eating Venom: Cytotoxicity as a Defensive Innovation and Its Co-Evolution with Hooding, Aposematic Marking, and Spitting

Panagides

Jackson

Ikonomopoulou

et al. 2017

Toxins

The cytotoxicity of the venom of 25 species of Old World elapid snake was tested and compared with the morphological and behavioural adaptations of hooding and spitting. We determined that, contrary to previous assumptions, the venoms of spitting species are not consistently more cytotoxic than those of closely related non-spitting species. While this correlation between spitting and non-spitting was found among African cobras, it was not present among Asian cobras. On the other hand, a consistent positive correlation was observed between cytotoxicity and utilisation of the defensive hooding display that cobras are famous for. Hooding and spitting are widely regarded as defensive adaptations, but it has hitherto been uncertain whether cytotoxicity serves a defensive purpose or is somehow useful in prey subjugation. The results of this study suggest that cytotoxicity evolved primarily as a defensive innovation and that it has co-evolved twice alongside hooding behavior: once in the Hemachatus + Naja and again independently in the king cobras (Ophiophagus). There was a significant increase of cytotoxicity in the Asian Naja linked to the evolution of bold aposematic hood markings, reinforcing the link between hooding and the evolution of defensive cytotoxic venoms. In parallel, lineages with increased cytotoxicity but lacking bold hood patterns evolved aposematic markers in the form of high contrast body banding. The results also indicate that, secondary to the evolution of venom rich in cytotoxins, spitting has evolved three times independently: once within the African Naja, once within the Asian Naja, and once in the Hemachatus genus. The evolution of cytotoxic venom thus appears to facilitate the evolution of defensive spitting behaviour. In contrast, a secondary loss of cytotoxicity and reduction of the hood occurred in the water cobra Naja annulata, which possesses streamlined neurotoxic venom similar to that of other aquatic elapid snakes (e.g., hydrophiine sea snakes). The results of this study make an important contribution to our growing understanding of the selection pressures shaping the evolution of snake venom and its constituent toxins. The data also aid in elucidating the relationship between these selection pressures and the medical impact of human snakebite in the developing world, as cytotoxic cobras cause considerable morbidity including loss-of-function injuries that result in economic and social burdens in the tropics of Asia and sub-Saharan Africa.

The American Society of Tropical Medicine and Hygiene

“…Of the three antivenoms tested, the highest efficacy shown by VPAV in neutralizing CTX is consistent with the composition of Indian N. naja venom (the immunogen) that contains predominantly CTXs. 11 Both the Thai N. kaouthia and Taiwanese N. atra venoms contain lower abundance of CTXs compare with venom of the Indian N. naja.…”

Section: Discussionmentioning

confidence: 99%

“…This is supported by the venom profiling where α-NTXs (with LD 50 values of 0.07-0.18 μg/g) made up nearly 40% abundance of the Pakistani N. naja venom, comparable to that found in the Thai monocled cobra. On the other hand, the venoms from the Indian and Sri Lankan species were known to contain much lesser α-NTXs (3-6%) 11 while being dominated by CTXs (higher LD 50 value > 1 μg/g). This phenomenon has great implication on the management practice of N. naja envenomation in South Asia, as imported antivenoms used in Sri Lanka, Bangladesh, Pakistan, and Nepal basically are sourced from India where most of the products are raised against snakes from a single source in Tamil Nadu (southeastern India).…”

Section: Discussionmentioning

confidence: 99%

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

Wong¹,

Tan²,

Tan³

2016

Abstract. Geographical variations of snake venoms can result in suboptimal effectiveness of Indian antivenoms that are currently used in most South Asian countries. This study investigated the toxicity and neutralization profile of the venom and toxins from Pakistani spectacled cobra, Naja naja, using VINS polyvalent antivenom (VPAV, India), Naja kaouthia monovalent antivenom (NKMAV, Thailand), and neuro bivalent antivenom (NBAV, Taiwan). Cationexchange and reverse-phase high-performance liquid chromatography fractionations followed by toxin identification through liquid chromatography-mass spectrometry (MS)/MS indicated that the venom comprised mainly of postsynaptic neurotoxins (NTXs) (long neurotoxins [LNTXs], 28.3%; short neurotoxins [SNTXs], 8%), cytotoxins (CTXs) (31.2%), and acidic phospholipases A 2 (12.3%). NKMAV is the most effective in neutralizing the lethal effect of the venom (potency = 1.1 mg venom/mL) and its LNTX (potency = 0.5 mg toxin/mL), consistent with the high content of LNTX in N. kaouthia venom. VPAV was effective in neutralizing the CTX (potency = 0.4 mg toxin/mL), in agreement with the higher CTX abundance in Indian cobra venom. All the three antivenoms were weak in neutralizing the SNTX (potency = 0.03-0.04 mg toxin/mL), including NBAV that was raised from the SNTX-rich Taiwanese cobra venom. In a challenge-rescue experiment, envenomed mice were prevented from death by a maximal dose of VPAV (intravenous 200 μL) but the recovery from paralysis was slow, indicating the need for higher or repeated doses of VPAV. Our results suggest that optimal neutralization for Pakistani N. naja venom may be achieved by improving the formulation of antivenom production to enhance antivenom immunoreactivity against long and SNTXs.