Identification of antigenic regions of the Erns protein for pig antibodies elicited during classical swine fever virus infection.
The structural glycoprotein E(rns) of classical swine fever virus (CSFV) is one of the major antibody targets upon infection of pigs with the virus. Molecular dissection of the structure of E(rns) would define the minimal immunodominant regions that induce antibody responses after infection and may thus help design an effective diagnostic reagent or vaccine. In this study, deletion analysis was made within amino acids (aa) 297 to 776 of the CSFV Alfort/187 polyprotein containing the large C-terminal portion of the E(rns) protein (aa 27 to 227), the entire E1 protein (aa 1 to 195), and the N-terminal portion of the E2 protein (aa 1 to 87). Various protein fragments with target deletions from N- or/and C-terminal ends were constructed with pET30, expressed in Escherichia coli and probed on Western blots with antisera from pigs infected with CSFV. This has resulted in the identification within E(rns) of three overlapping antigenic regions: AR1(E(rns)aa 65-145), AR2 (E(rns)aa 84-160) and AR3 (E(rns)aa 109-220). N- or C-terminal deletions as small as 3 residues introduced into these regions disrupt their reactivity with antibodies, indicating that they are the minimum requirements for recognition by pig antibodies. The three minimal antigenic regions correlated well with the hydropathy profiles and the 3D structural model of E(rns). Each individual region and a protein fragment containing AR1, AR2 and AR3 reacted equally well with pig anti-CSFV sera. Since variable and conserved sequences are present within the three overlapping antigenic regions of E(rns) of different pestiviruses, specific serological detection of CSFV infection or broad detection of pestivirus infections may be achieved with the use of a single E(rns) region or a combination of two or three E(rns) regions.
Lin
Min
M
Animal Diseases Research Institute, Nepean, Ontario, Canada K2H 8P9. linm@inspection.gc.ca
Trottier
Erin
E
Pasick
John
J
Sabara
Marta
M
D000595:Amino Acid Sequence; D000818:Animals; D000956:Antigens, Viral / Q000276:immunology*; D006691:Classical Swine Fever / Q000276:immunology* / Q000378:metabolism; D006692:Classical Swine Fever Virus / Q000472:pathogenicity*; D018604:Epitope Mapping; D007074:Immunoglobulin G / Q000276:immunology*; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000276:immunology / Q000378:metabolism; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D013552:Swine; D014759:Viral Envelope Proteins / Q000276:immunology* / Q000378:metabolism
D000956:Antigens, Viral; D007074:Immunoglobulin G; D011994:Recombinant Proteins; D014759:Viral Envelope Proteins