title: Evidence of a humoral immune response against the prokaryotic expressed N-terminal autoprotease (N(pro)) protein of bovine viral diarrhoea virus.
abstract: Bovine viral diarrhoea virus (BVDV) is an economically important pathogen of cattle and sheep belonging to the genus Pestivirus of the family Flaviviridae. Although the BVDV non-structural N-terminal protease (N(pro)) acts as an interferon antagonist and subverts the host innate immunity, little is known about its immunogenicity. Hence, we expressed a recombinant BVDV N(pro)-His fusion protein (28 kDa) in E. coli and determined the humoral immune response generated by it in rabbits. The antigenicity of the N(pro) protein was confirmed by western blot using anti-BVDV hyperimmune cattle, sheep and goat serum, and anti-N(pro) rabbit serum. When rabbits were immunized with the N(pro) protein, a humoral immune response was evident by 4 weeks and persisted till 10 weeks post immunization as detected by ELISA and western blot. Despite N(pro)-specific antibodies remaining undetectable in 80 serum samples from BVDV-infected sheep and goats, BVDV hyperimmune sera along with some of the field cattle, sheep and goat sera with high BVDV neutralizing antibody titres were found positive for N(pro) antibodies. Our results provide evidence that despite the low immunogenicity of the BVDV N(pro) protein, a humoral immune response is induced in cattle, sheep and goats only with repeated BVDV exposure.
authors.affiliation: High Security Animal Disease Laboratory, Indian Veterinary Research Institute, Anand Nagar, Bhopal 462 021, India. mishranir@rediffmail.com
authors.forename: Niranjan
authors.initials: N
authors.lastname: Mishra
authors.forename: Katherukamem
authors.initials: K
authors.lastname: Rajukumar
authors.forename: Shruti Shrikant
authors.initials: SS
authors.lastname: Pitale
authors.forename: Anil
authors.initials: A
authors.lastname: Prakash
authors.forename: Ram Kumar
authors.initials: RK
authors.lastname: Nema
authors.forename: Sthita Pragnya
authors.initials: SP
authors.lastname: Behera
authors.forename: Shiv Chandra
authors.initials: SC
authors.lastname: Dubey
mesh_terms: D000818:Animals; D001912:Bovine Virus Diarrhea-Mucosal Disease / Q000276:immunology* / Q000821:virology*; D002417:Cattle; D001908:Diarrhea Viruses, Bovine Viral / Q000201:enzymology* / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D004926:Escherichia coli / Q000378:metabolism; D006041:Goats; D007107:Immune System; D056724:Immunity, Humoral; D008297:Male; D008954:Models, Biological; D010447:Peptide Hydrolases / Q000737:chemistry* / Q000276:immunology; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000737:chemistry; D011994:Recombinant Proteins / Q000737:chemistry
chemical_list: D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D010447:Peptide Hydrolases