title: Epitope mapping of the V3 domain of feline immunodeficiency virus envelope glycoprotein by monoclonal antibodies.
abstract: A panel of six IgG monoclonal antibodies (MAbs) was produced by immunizing mice with a 22 amino acid synthetic peptide, designated V3.3, of the third variable region of feline immunodeficiency virus (FIV) envelope glycoprotein. This peptide is known to induce neutralizing antibodies in cats. In ELISA all MAbs reacted with purified SDS-disrupted FIV and in flow cytometry all MAbs stained permeated, persistently infected FL4 cells but not unfixed FL4 cells; this indicated that the MAbs recognize essentially cryptic epitopes of the gp100 V3 loop. By direct ELISA using partially overlapping synthetic peptides and by competition binding studies, the anti-V3.3 MAbs were shown to detect at least four distinct epitopes, two located in the amino-terminal half and two in the carboxy-terminal half of the sequence. When tested for neutralizing activity by the syncytium inhibition assay in Crandell feline kidney cells, all anti-V3.3 MAbs neutralized FIV at high dilution. However, at low dilution two MAbs exhibited much less neutralizing activity. These results indicate that the V3 region of FIV contains multiple epitopes involved in neutralization.
authors.affiliation: Department of Biomedicine, University of Pisa, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Lombardi
authors.forename: C
authors.initials: C
authors.lastname: Massi
authors.forename: F
authors.initials: F
authors.lastname: Tozzini
authors.forename: L
authors.initials: L
authors.lastname: Zaccaro
authors.forename: A
authors.initials: A
authors.lastname: Bazzichi
authors.forename: P
authors.initials: P
authors.lastname: Bandecchi
authors.forename: C
authors.initials: C
authors.lastname: La Rosa
authors.forename: M
authors.initials: M
authors.lastname: Bendinelli
authors.forename: C
authors.initials: C
authors.lastname: Garzelli
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000914:Antibodies, Viral / Q000096:biosynthesis*; D001667:Binding, Competitive; D002415:Cats; D002460:Cell Line; D018604:Epitope Mapping; D015686:Gene Products, env / Q000737:chemistry / Q000276:immunology*; D016089:Immunodeficiency Virus, Feline / Q000737:chemistry / Q000276:immunology*; D007074:Immunoglobulin G / Q000096:biosynthesis; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D009500:Neutralization Tests; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D015686:Gene Products, env; D007074:Immunoglobulin G; D010446:Peptide Fragments