title: Single amino acid mutations in the capsid switch the neutralization phenotype of porcine circovirus 2.
abstract: Porcine circovirus 2 (PCV2) is the causative agent of porcine circovirus-associated diseases in pigs. Previously, it was demonstrated that mAbs 16G12, 38C1, 63H3 and 94H8 directed against the PCV2 capsid protein recognize PCV2 strains Stoon-1010 (PCV2a), 48285 (PCV2b), 1121 (PCV2a), 1147 (PCV2b) and II9F (PCV2b), but only neutralize Stoon-1010 and 48285. This points to the existence of two distinct PCV2 neutralization phenotypes: phenotype α (mAb recognition with neutralization; Stoon-1010 and 48285) and phenotype β (mAb recognition without neutralization; 1121, 1147 and II9F). In the present study, amino acids that are important in determining the neutralization phenotype were identified in the capsid. Mutation of T at position 190 to A in strain 48285 (phenotype α) resulted in a capsid resembling that of strain 1147 (phenotype β) and caused a loss of neutralization (switch from α to β). Mutations of P at position 151 to T and A at position 190 to T in strain II9F (phenotype β) resulted in a capsid resembling that of strain 48285 (phenotype α) and gave a gain of neutralization (switch from β to α). Mutations of T at position 131 to P and of E at position 191 to R in Stoon-1010 (phenotype α) changed the capsid into that of 1121 (phenotype β) and reduced neutralization (switch from α to β). This study demonstrated that single amino acid changes in the capsid result in a phenotypic switch from α to β or β to α.
authors.affiliation: Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
authors.forename: Dipongkor
authors.initials: D
authors.lastname: Saha
authors.forename: David J
authors.initials: DJ
authors.lastname: Lefebvre
authors.affiliation: Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
authors.forename: Karen
authors.initials: K
authors.lastname: Ooms
authors.affiliation: Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
authors.forename: Liping
authors.initials: L
authors.lastname: Huang
authors.affiliation: Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
authors.forename: Peter L
authors.initials: PL
authors.lastname: Delputte
authors.affiliation: Department of Health Care and Biotechnology, KATHO Catholic University College of South-West Flanders, Wilgenstraat 32, 8800 Roeselare, Belgium.
authors.forename: Jan
authors.initials: J
authors.lastname: Van Doorsselaere
authors.affiliation: Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
authors.forename: Hans J
authors.initials: HJ
authors.lastname: Nauwynck
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D057134:Antibodies, Neutralizing / Q000276:immunology*; D000914:Antibodies, Viral / Q000276:immunology*; D036022:Capsid Proteins / Q000235:genetics* / Q000276:immunology*; D017925:Circovirus / Q000235:genetics* / Q000276:immunology*; D020125:Mutation, Missense; D009500:Neutralization Tests
chemical_list: D000911:Antibodies, Monoclonal; D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D036022:Capsid Proteins