title: Antibody-induced internalization of viral glycoproteins in pseudorabies virus-infected monocytes and role of the cytoskeleton: a confocal study.
abstract: Addition of pseudorabies virus (PrV)-specific polyclonal immunoglobulins to PrV-infected monocytes induces internalization of plasma membrane anchored viral glycoproteins. This process may interfere with antibody-dependent cell lysis and resembles the well-studied physiological endocytosis process. A confocal study was designed to investigate whether the major cellular components, involved in physiological endocytosis (clathrin, actin, dynein and microtubules), play a role in this virological internalization process. In order to visualize the interaction of endosomes, which contain the internalized viral glycoproteins, with clathrin, actin, dynein and microtubules, a double labeling of viral glycoproteins and different cellular proteins was performed. Porcine monocytes were inoculated with the PrV-strain 89V87 at a multiplicity of infection of 50 for 13h. After the addition of FITC-labeled porcine polyclonal PrV-specific antibodies, cells were fixed with para-formaldehyde at different time points and afterwards permeabilized. The different cellular components were visualized with monoclonal antibodies and a Texas Red-conjugate, with the exception of actin, which was stained with phalloidin-Texas Red. The cells were analyzed by confocal microscopy. A clear co-localization was observed between the viral glycoproteins and clathrin and dynein during the internalization process. The microtubules were in close contact with the internalized vesicles. For actin no co-localization could be observed. It can be stated that clathrin, dynein and microtubules, important components during physiological endocytosis, are also of importance during the antibody-induced internalization of viral glycoproteins.
authors.affiliation: Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium.
authors.forename: Gerlinde R
authors.initials: GR
authors.lastname: Van de Walle
authors.forename: Herman W
authors.initials: HW
authors.lastname: Favoreel
authors.forename: Hans J
authors.initials: HJ
authors.lastname: Nauwynck
authors.forename: Patrick
authors.initials: P
authors.lastname: Van Oostveldt
authors.forename: Maurice B
authors.initials: MB
authors.lastname: Pensaert
mesh_terms: D000199:Actins / Q000276:immunology; D000818:Animals; D000914:Antibodies, Viral / Q000276:immunology*; D002966:Clathrin / Q000276:immunology; D003599:Cytoskeleton / Q000276:immunology*; D004398:Dyneins / Q000276:immunology; D011558:Herpesvirus 1, Suid / Q000276:immunology*; D007963:Leukocytes, Mononuclear / Q000276:immunology* / Q000378:metabolism / Q000821:virology; D018613:Microscopy, Confocal; D008870:Microtubules / Q000276:immunology; D011557:Pseudorabies / Q000097:blood / Q000276:immunology* / Q000821:virology; D013552:Swine; D013553:Swine Diseases / Q000097:blood / Q000276:immunology* / Q000821:virology; D014764:Viral Proteins / Q000276:immunology* / Q000378:metabolism
chemical_list: D000199:Actins; D000914:Antibodies, Viral; D002966:Clathrin; D014764:Viral Proteins; D004398:Dyneins