Expression of Immunodominant Regions of E2 from an Indian Isolate of Classical Swine Fever Virus Bachan Ram1, Bhattacharya Supriya2, Saini Mohini1, Rama T.1, Rana Mashidur1, Gupta Praveen K.2,* 1Division of Biochemistry, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India 2Division of Veterinary Biotechnology, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India *Corresponding author: PK Gupta; E-mail: praveen.indian@gmail.com
Online published on 19 July, 2019. Abstract Classical swine fever (CSF) is an economically important contagious fatal disease of domestic pigs and wild boars. This disease is caused by classical swine fever virus (CSFV), a member of the Pestivirus genus within the Flaviviridae family. Upon infection, three proteins of CSFV, namely E2, Erns and NS3 induce detectable antibodies. Since E2 is a major glycoprotein that produces neutralizing antibodies and provides protective immunity, it is widely used as a marker for measuring vaccine efficacy and antibody titer. In the present study, immunodominant regions of E2 glycoprotein from Indian field isolate of CSFV were expressed in E. coli. The 336 amino acid long N-terminal ectodomain (full-E2) and the 207 amino acid (aa 173–380) long C-terminal immunodominant region (partial-E2) were expressed and purified as 54kDa and 24kDa recombinant proteins, respectively. Both full-E2 and partial-E2 recombinant proteins were also characterized using MALDI-TOF-TOF analysis as CSFV-E2 structural proteins. The yield of purified full-E2 and partial-E2 recombinant protein was 26 mg and 84 mg/liter culture, respectively. For raising hyperimmune sera against these proteins, chickens and rabbits were immunized with 200μg purified protein and boosted three times with 100μg purified protein intramuscularly. The sera collected one week after last booster were analyzed for CSFV-specific IgG antibody response using purified CSFV as coating antigen in ELISA. The results revealed that full-E2 induced better antibody response in both rabbits and chicken as compared to partial-E2. This study also indicated that these recombinant E2 proteins can be used as diagnostic antigen in ELISA. Top Keywords CSFV, recombinant, E2, prokaryotic expression, ELISA. Top |