مجله بیوتکنولوژی کشاورزی (May 2023)
Induction of specific immune responses in inoculated mice by a eukaryotic plasmid expressing the G1 epitope of bovine ephemeral fever virus
Abstract
Objective Bovine ephemeral fever (BEF) is an arthropod-borne viral disease of cattle and water buffalos which causes considerable economic and commercial losses in the cattle industry. The G glycoprotein of bovine ephemeral fever virus (BEFV) has been identified as a plausible candidate to product recombinant vaccines against this disease. The aim of this study was to investigate the immunogenicity of a eukaryotic plasmid expressing the G1 epitope of bovine ephemeral fever virus G glycoprotein as a possible DNA vaccine in mice. Materials and methods At first, a eukaryotic plasmid expressing the G1 epitope of bovine ephemeral fever virus G glycoprotein was constructed and designated as pEGFPN1-G1. After transfection of the pEGFPN1-G1 recombinant construct to human embryonic kidney 293 (HEK 293) cells, the expression of G1 protein was confirmed by indirect immunofluorescent staining (IFA). Immunization experiments were intramuscularly carried out by inoculating 6-8-week-old female mice in four groups with five repeats, including the pEGFPN1-G1 recombinant construct, bovine ephemeral fever-inactivated vaccine, pEGFP-N1 plasmid alone, and phosphate-buffered saline (PBS) (1X) three times with 2-week intervals. Fourteen days after the last immunization, the animals were bled and the resulting sera were tested for anti-G1-specific antibodies by immunoblotting analysis, indirect enzyme-linked immunosorbent assay (ELISA) and virus neutralisation (VN) test. The optical density values of all the serum samples obtained from the ELISA assay were statistically analyzed in the form of a completely randomized design with four treatments and five replications using SAS software. Results Immunoblotting analysis and statistical analysis of serum samples obtained from the ELISA assay showed that the pEGFPN1-G1 recombinant construct was able to elicit specific antibodies against G1 antigen of bovine ephemeral fever virus in mice. However, the serum of mice inoculated with this plasmid could not neutralize the replicating bovine ephemeral fever virus in virus neutralization assay. Conclusions Since the pEGFPN1-G1 recombinant construct had the ability to produce specific antibodies against the G1 antigen of bovine ephemeral fever virus, the results of this study can be a step towards the development of new vaccines for bovine ephemeral fever in the future.
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