Prokaryotic expression and purification of highly soluble partial glycoprotein erns of indian strain of classical swine fever virus

Classical swine fever (CSF) or hog cholera, caused by a positive stranded RNA virus belonging to the genus Pestivirus of the Flaviviridae family, is highly contagious and fatal disease of pigs. We report the novel design of construct for production of highly soluble glycoprotein Erns fragment using prokaryotic expression system. A truncated fragment of the Erns gene (coding for aa 109-170) denoted as 'Erns-Ag' was subcloned and expressed as hexa-histidine tag fusion on both terminus of protein in Escherichia coli. The highly soluble recombinant Erns-Ag protein with purity >95 % was purified by one step Ni-NTA affinity chromatography under native condition. Anti Erns-Ag polyclonal antibodies raised in guinea pig was found to react with CSFV antigen in infected MDCK cell line during immunoperoxidase test. The described methodology of producing a highly soluble recombinant protein with native conformation would likely to assist in development of differential diagnostic test as well as its application in raising hyperimmune sera for detection of CSFV antigen either in tissue materials or infected cell lines.