Ligation of cell surface heparan sulfate proteoglycans by antibody-coated beads stimulates phagocytic uptake into epithelial cells: a model for cellular invasion by Neisseria gonorrhoeae.
Binding of a particular opacity outer membrane protein (Opa) of Neisseria gonorrhoeae to cell surface heparan sulfate proteoglycans (HSPGs) of epithelial cells results in tight bacterial adherence; however, the role of this ligand-receptor interaction in triggering the subsequent bacterial internalization step is uncertain. Here we have used latex beads coated with HSPG-ligating antibodies as an in vitro model to study the role of HSPGs in gonococcal uptake into epithelial cells. Beads and gonococci showed the same cell line-specified adherence patterns and increase in phagocytic uptake mediated by serum or purified vitronectin (Vn). Heparitinase digestion as well as antibody competition experiments indicate that a critical level of HSPG ligation is necessary and sufficient to trigger phagocytic uptake into epithelial cells. Vn was found to specifically enhance HSPG-dependent phagocytic uptake while phagocytosis resulting from the ligation of other cell surface receptors was unaffected in the presence of Vn. Pharmacological studies with PKC inhibitors suggest a role for PKC in phagocytic uptake of HSPG-ligating beads. The use of drugs impairing cytoskeletal functions indicates that HSPG-dependent phagocytosis requires actin polymerization by a process distinct from receptor-mediated endocytosis.
Max-Planck-Institut für Biologie, Abteilung Infektionsbiologie, Spemannstrasse 34, Tübingen, D-72076, Germany.
C
C
Dehio
E
E
Freissler
C
C
Lanz
O G
OG
Gómez-Duarte
G
G
David
T F
TF
Meyer
D000199:Actins / Q000378:metabolism; D000907:Antibodies, Bacterial / Q000276:immunology / Q000378:metabolism*; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000378:metabolism*; D000942:Antigens, Bacterial / Q000276:immunology / Q000378:metabolism; D001422:Bacterial Adhesion / Q000502:physiology; D001704:Biopolymers / Q000378:metabolism; D003432:Cross-Linking Reagents; D004705:Endocytosis / Q000187:drug effects / Q000276:immunology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism* / Q000382:microbiology; D006367:HeLa Cells; D019812:Heparan Sulfate Proteoglycans / Q000276:immunology / Q000378:metabolism* / Q000493:pharmacokinetics*; D006801:Humans; D008024:Ligands; D008863:Microspheres; D009344:Neisseria gonorrhoeae / Q000276:immunology / Q000378:metabolism; D010587:Phagocytosis / Q000187:drug effects / Q000276:immunology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000276:immunology / Q000378:metabolism; D012680:Sensitivity and Specificity; D014407:Tumor Cells, Cultured / Q000166:cytology / Q000378:metabolism / Q000382:microbiology; D019096:Vitronectin / Q000494:pharmacology
D000199:Actins; D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D001704:Biopolymers; D003432:Cross-Linking Reagents; D004791:Enzyme Inhibitors; D019812:Heparan Sulfate Proteoglycans; D008024:Ligands; D011956:Receptors, Cell Surface; D019096:Vitronectin; D011493:Protein Kinase C