title: African swine fever virus structural protein p72 contains a conformational neutralizing epitope.
abstract: We have previously described a monoclonal antibody (mAb 135D4) to an unidentified 70- to 72-kDa African swine fever virus (ASFV) protein that exhibited high levels of neutralizing activity against various virulent ASFV isolates. Here, we identify the reactive ASFV protein as the major virus structural protein p72. In vitro-translated products of the p72 protein gene were specifically immunoprecipitated by mAb 135D4. Immunoprecipitation of a nested set of truncated p72 in vitro translation products defined the region between amino acid residues 400 and 404 as necessary for mAb 135D4 reactivity. Five partially overlapping peptides (15mers) covering residues 388-446 failed to react with mAb 135D4, suggesting the conformational dependence of the epitope. Supporting this interpretation, larger in vitro translation products representing residues 56-282, 159-361, 360-508, and 507-646 also failed to react with mAb 135D4. Consistent with its involvement in virus neutralization, immunoelectromicroscopy, using a rabbit antiserum against mAb 135D4-purified p72, located the protein on the surface of unenveloped virus particles.
authors.affiliation: Plum Island Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Greenport, New York 11948-0848.
authors.forename: M V
authors.initials: MV
authors.lastname: Borca
authors.forename: P
authors.initials: P
authors.lastname: Irusta
authors.forename: C
authors.initials: C
authors.lastname: Carrillo
authors.forename: C L
authors.initials: CL
authors.lastname: Afonso
authors.forename: T
authors.initials: T
authors.lastname: Burrage
authors.forename: D L
authors.initials: DL
authors.lastname: Rock
mesh_terms: D000358:African Swine Fever Virus / Q000276:immunology*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002213:Capsid / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D036022:Capsid Proteins; D002478:Cells, Cultured; D004279:DNA, Viral; D000939:Epitopes / Q000737:chemistry / Q000276:immunology*; D008969:Molecular Sequence Data; D009500:Neutralization Tests; D011233:Precipitin Tests; D014176:Protein Biosynthesis; D011487:Protein Conformation; D013552:Swine
chemical_list: D036022:Capsid Proteins; D004279:DNA, Viral; D000939:Epitopes; C063745:capsid protein p72, African swine fever virus