Development of a Broad-Spectrum Antiserum against Cobra Venoms Using Recombinant Three-Finger Toxins.

Bing-Sin Liu,Bo-Rong Jiang,Wen-Chin Hsieh,Kai-Chieh Hu,Min-Han Lin,Wang-Chou Sung,Chien-Hsin Liu

doi:10.3390/toxins13080556

Bing-Sin Liu, Bo-Rong Jiang + Show 5 more

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https://doi.org/10.3390/toxins13080556

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Abstract

Three-finger toxins (3FTXs) are the most clinically relevant components in cobra (genus Naja) venoms. Administration of the antivenom is the recommended treatment for the snakebite envenomings, while the efficacy to cross-neutralize the different cobra species is typically limited, which is presumably due to intra-specific variation of the 3FTXs composition in cobra venoms. Targeting the clinically relevant venom components has been considered as an important factor for novel antivenom design. Here, we used the recombinant type of long-chain α-neurotoxins (P01391), short-chain α-neurotoxins (P60770), and cardiotoxin A3 (P60301) to generate a new immunogen formulation and investigated the potency of the resulting antiserum against the venom lethality of three medially important cobras in Asia, including the Thai monocled cobra (Naja kaouthia), the Taiwan cobra (Naja atra), and the Thai spitting cobra (Naja Siamensis) snake species. With the fusion of protein disulfide isomerase and the low-temperature settings, the correct disulfide bonds were built on these recombinant 3FTXs (r3FTXs), which were confirmed by the circular dichroism spectra and tandem mass spectrometry. Immunization with r3FTX was able to induce the specific antibody response to the native 3FTXs in cobra venoms. Furthermore, the horse and rabbit antiserum raised by the r3FTX mixture is able to neutralize the venom lethality of the selected three medically important cobras. Thus, the study demonstrated that the r3FTXs are potential immunogens in the development of novel antivenom with broad neutralization activity for the therapeutic treatment of victims involving cobra snakes in countries.

Highlights

Snake envenoming remains a threat to public health worldwide and leads to an estimated 1,841,000 snakebite cases and over 94,000 fatalities per year [1,2]
Key Contribution: This study presents the potency of recombinant three-finger toxins for the development of animal antiserum with cross-neutralization potency against the venoms of three medically important cobra species
With the fusion of Disulfide bond C (DsbC) isomerase, three recombinant 3FTXs (r3FTXs) with correct disulfide bonds were generated with the E coli expression systems, which was confirmed by MS and circular dichroism (CD) characterization

Summary

Introduction

Snake envenoming remains a threat to public health worldwide and leads to an estimated 1,841,000 snakebite cases and over 94,000 fatalities per year [1,2]. In Asia, approximately 12–34% of snakebite envenoming was estimated to be caused by cobra species [3,4,5,6]. Administration of the antivenom is the recommended approach for the therapy of snakebite envenomation, which consists of neutralizing antibodies to block the toxicity of venom components. According to the hospital reports and records, there are nine cobra species ranked as category 1 in Asia regions—i.e., the most medical important species responsible for the highest morbidity and mortality [7]. In 2017, the WHO restated that snakebite is a neglected tropical disease and aimed to develop effective strategies to decrease the life-threatening accidents by 50% before 2030 [14,15,16]

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