Cloning and Expression of N-CFTX-1 Antigen from Chironex fleckeri in Escherichia coli and Determination of Immunogenicity in Mice

Background: most jellyfish species are poisonous. human victims of jellyfish sting each year are 120 million. chironex fleckeri is a venomous box jellyfish that inflicts painful and potentially fatal stings to humans. the cftx-1 is one of the antigenic proteins of venom that is suggested to stimulate the immune system for treatment and vaccine. this study aimed to clone and express the cftx-1 antigen in e. coli and then to determine the synthesis of related antibody in the mice. methods: the study was performed in the persian gulf and oman sea ecology research center, bandar abbas, iran in autumn 2016. the synthetic cftx-1 gene in puc57 plasmid was purchased from nedaye fan company. the 723 bp fragment of n-cftx-1 was amplified by pcr, puc57 plasmid containing cftx-1 with bamhi sali restriction enzyme sites were subcloned in pet28a [+] expression vector and transformed into e. coli bl21 (de3). the cftx-1 gene expression was induced by iptg. then antibody produced from the mice serum were isolated and confirmed by elisa. after protein purification, resulted antigen was injected to mice in 4 repeats and then evaluated the rate of antibody in mice serum. mice were challenged by the carybdea alata. results: the 726 bp of n-cftx-1 were cloned in a vector of expression pet28a [+] and confirmed by pcr, sequencing and enzymatic analysis. moreover, the recombinant protein was confirmed by sds-page and western blotting. then the antibody was isolated from mice serum and confirmed by elisa test. the results showed that immunized mice tolerated 50x ld50^1 of jellyfish venom. conclusion: the cftx-1 recombinant protein was able to protect the balb/c mice against jellyfish venom. the produced protein can be used as a candidate for vaccine against jellyfish venom.