Isolation of polyclonal scFv fragments against venomous snakes of Iran and evaluation of its capability in neutralizing the venom

Several species of dangerous snakes are found in Iran and, according to the Emergency Response Center of Iran from 2002 to 2011, 53,787 Iranians have suffered from snakebite. Although the mortalities caused by snakebite are very low, snakebite-related amputations are still a major concern. Currently, anti-venom polyclonal antibodies derived from animals, such as horses are used to treat snakebites; however, in some cases they can cause anaphylactic shock and serum sickness. In line with this premise, generation of recombinant anti-venom antibodies can be considered as an alternative strategy. Single-chain fragment variable (scFv) antibodies offer several advantages compared to the whole antibodies, including ease of production, high affinity and specificity. In the present study, scFv antibodies were selected against the venom of the most poisonous snakes in Iran using phage display technology. Phage particles harboring anti-venom specific scFv were separated and scFv antibodies were produced in bacteria. In-vitro assay showed that polyclonal scFvs specifically bind to the venom. Furthermore, in-vivo experiment in mice BALB/c indicated effective toxin neutralization using 20 µg of polyclonal scFv. Our study indicates the neutralizing capacity of anti-venom polyclonal scFvs, although further neutralization assays are needed to confirm their effectiveness.