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

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.

Exploring the Utility of Recombinant Snake Venom Serine Protease Toxins as Immunogens for Generating Experimental Snakebite Antivenoms

“…Consequently, there have been many experimental attempts to improve conventional antivenoms by focusing the immune response towards the generation of polyclonal antibodies against key pathogenic toxins, rather than all toxins, via the use of immunogens distinct from crude venom. Examples of such strategies include the use of strings of linear epitopes [ 49 ], virus-like particles decorated in conserved epitopes [ 44 ], recombinantly expressed venom toxins [ 50 ] and recombinantly expressed consensus toxins [ 51 ].…”

Exploring the utility of recombinantly expressed snake venom serine protease toxins as immunogens for generating experimental snakebite antivenoms

“…Consequently, there have been many experimental attempts to improve conventional antivenoms by focusing the immune response towards the generation of polyclonal antibodies against key pathogenic toxins, rather than all toxins, via the use of immunogens distinct from crude venom. Examples of such strategies include the use of strings of linear epitopes (49), virus-like particles decorated in conserved epitopes (50), recombinantly expressed venom toxins (51) and recombinantly expressed consensus toxins (52).…”

Evaluating Antivenom Efficacy against Echis carinatus Venoms—Screening for In Vitro Alternatives

“…This could be because toxins that are low in toxicity could be highly immunogenic or vice versa. For instance, in the case of neurotoxic venoms, three-finger toxins (3FTx) are highly neurotoxic but show low immunogenicity due to their small size [ 29 ]. To tackle this, some research groups have attempted to isolate the toxic component of venoms and quantified antibodies against them with better correlation [ 30 ].…”