title: Selective interference with P protein binding to paramyxovirus nucleocapsids.
abstract: We previously observed that some anti-nucleoprotein monoclonal antibodies were able to displace P protein from Sendai virus (SV) nucleocapsid cores. The current work extends that observation by showing that such antibody-mediated P displacement is not unique to Sendai virus nucleocapsids, but can also occur with nucleocapsids of a related human respiratory pathogen. Anti-NP antibody prevents binding of SV P protein to nucleocapsids from human parainfluenza virus type 1 (PIV1) or from SV. Antibody also prevents binding of PIV1 P protein to PIV1 nucleocapsids, but not to SV nucleocapsids. We have also examined the stoichiometry of antibody interference with P binding, to determine how large a nucleocapsid region can be protected from P binding by a single antibody molecule. We found that approximately 40 antibody molecules per nucleocapsid complex can block attachment of most P protein. This indicates that a single antibody molecule can prevent P binding to a region representing about 65 nucleoprotein monomers on the nucleocapsid core.
authors.affiliation: Department of Virology & Molecular Biology, St. Jude Children's Research Hospital, Memphis, TN 38101.
authors.forename: K W
authors.initials: KW
authors.lastname: Ryan
authors.forename: U F
authors.initials: UF
authors.lastname: Power
mesh_terms: D000914:Antibodies, Viral / Q000378:metabolism*; D000937:Antigen-Antibody Reactions; D002213:Capsid / Q000378:metabolism*; D000939:Epitopes / Q000378:metabolism; D006801:Humans; D019590:Nucleocapsid Proteins; D009698:Nucleoproteins; D010222:Parainfluenza Virus 1, Human / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism*; D011485:Protein Binding; D014758:Viral Core Proteins / Q000276:immunology*; D014764:Viral Proteins / Q000378:metabolism*
chemical_list: D000914:Antibodies, Viral; D000939:Epitopes; D019590:Nucleocapsid Proteins; D009698:Nucleoproteins; C055859:P protein, Sendai virus; D010750:Phosphoproteins; D014758:Viral Core Proteins; D014764:Viral Proteins; C068855:P protein, parainfluenza virus 1