Cloning and expression of truncated ORF2 as a vaccine candidate against hepatitis E virus
Hepatitis E virus infection is responsible for acute viral hepatitis and associated with high mortality and still birth in pregnant women in developing countries. We report expression of truncated forms of HEV ORF2 as potential vaccine candidates for nanoparticle-based delivery. These two truncated ORF2 proteins (54 kDa and 26 kDa) have been reported to be highly immunogenic and can be used as nanoparticle-based vaccine candidate. The bacterial expressed protein was purified by affinity chromatography and further confirmed by western blot using anti-HEV antibody. The chitosan nanoemulsion was synthesized using ultrasonic waves. The nanoparticle size was found to be 120–160 nm and the entrapment efficiency of purified truncated ORF2 proteins within these nanoparticles was 70% (26 kDa) and 59% (54 kDa). In cell cytotoxicity analysis, 100 µg/mL nanoemulsion was found suitable for cell viability in both HeLa and THP1 cell lines. Release kinetics of encapsulated proteins at physiological pH 7.4 showed 26–59% and 9.7–40% release of 26 kDa and 54 kDa protein within 1 h that gradually increased with time (48 h). Encapsulated proteins were found to be unstable at pH 1.2.
KeywordsChitosan Nanoemulsion Hepatitis E virus Truncated ORF2
Authors SS, DR and RS are thankful to Jaypee Institute of Information Technology and BN is thankful to AIIMS for the support for carrying out research work. DR and RS are also thankful to DST-INSPIRE (IF 150454 and IF 150897), Government of India for the fellowship and contingency Grant.
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Conflict of interest
All authors hereby declare that there is no conflict of interest.