Fusion regulation proteins on the cell surface: isolation and characterization of monoclonal antibodies which enhance giant polykaryocyte formation in Newcastle disease virus-infected cell lines of human origin.
Newcastle disease virus (NDV)-infected HeLa and FL cells showed small polykaryocytes at about 24 h postinfection, while the addition of anti-FL-cell rabbit, rat, or mouse serum to the NDV-infected cells gave rise to giant polykaryocytes at 15 h postinfection. We isolated three monoclonal antibodies (MAbs) (4-5-1, 6-1-13, and 7-2-1) capable of enhancing giant polykaryocyte formation in NDV-infected HeLa cells. These MAbs immunoprecipitated gp80 or gp135, which were detected mainly on the surface of HeLa cells. A functionally intact F protein was essential for antibody-enhanced cell fusion, and hemagglutinating (receptor-binding) activity of HN protein was involved in the fusion at an early stage; that is, the MAbs enhanced NDV-mediated syncytium formation. These molecules were considered to have the ability to regulate NDV-mediated cell fusion and thus were designated fusion regulation protein (FRP)-1 (gp80) and FRP-2 (gp135). Anti-FRP MAbs enhanced the susceptibility of cells to fusion activity of NDV. Anti-FRP-1 MAbs reacted with a molecule on the surface of every cell derived from humans and monkeys but showed no cross-reactivity with mouse or hamster cells. FRP-2 could be detected in limited cell lines of human origin.
Ito
Y
Y
Department of Microbiology, Mie University School of Medicine, Japan.
Komada
H
H
Kusagawa
S
S
Tsurudome
M
M
Matsumura
H
H
Kawano
M
M
Ohta
H
H
Nishio
M
M
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D002459:Cell Fusion; D002460:Cell Line; D006224:Cricetinae; D004591:Electrophoresis, Polyacrylamide Gel; D005455:Fluorescent Antibody Technique; D015726:Giant Cells / Q000166:cytology; D015707:HN Protein / Q000502:physiology; D006367:HeLa Cells; D006801:Humans; D007668:Kidney; D008565:Membrane Proteins / Q000276:immunology / Q000502:physiology*; D009522:Newcastle disease virus / Q000502:physiology*; D011233:Precipitin Tests; D015531:Radioimmunoprecipitation Assay; D014760:Viral Fusion Proteins / Q000502:physiology
D000911:Antibodies, Monoclonal; D015707:HN Protein; D008565:Membrane Proteins; D014760:Viral Fusion Proteins