title: Chlamydia pneumoniae uses the mannose 6-phosphate/insulin-like growth factor 2 receptor for infection of endothelial cells.
abstract: Several mechanisms for attachment and entry of Chlamydia have been proposed. We previously determined that the major outer membrane protein of Chlamydia trachomatis is glycosylated with a high-mannose oligosaccharide, and a similar structure inhibited the attachment and infectivity of C. trachomatis in epithelial cells. Because insulin-like growth factor 2 (IGF2) was shown to enhance the infectivity of Chlamydia pneumoniae but not C. trachomatis in endothelial cells, a hapten inhibition assay was used to analyze whether the mannose 6-phosphate (M6P)/IGF2 receptor that also binds M6P could be involved in infection of endothelial cells (HMEC-1) by Chlamydia. M6P and mannose 6-phosphate-poly[N-(2-hydroxyethyl)-acrylamide] (M6P-PAA) inhibited the infectivity of C. pneumoniae AR-39, but not C. trachomatis serovar UW5 or L2, while mannan inhibited the growth of C. trachomatis, but not C. pneumoniae. Using metabolically labeled organisms incubated with cells at 4 degrees C (organisms attach but do not enter) or at 37 degrees C (organisms attach and are internalized), M6P-PAA was shown to inhibit attachment and internalization of C. pneumoniae in endothelial cells but did not inhibit attachment or internalization of C. trachomatis serovar E or L2. These findings indicate that C. pneumoniae can utilize the M6P/IGF2 receptor and that the use of this receptor for attachment and entry differs between C. pneumoniae and C. trachomatis.
authors.affiliation: Department of Pathobiology, Box 357238, University of Washington, Seattle, WA 98195, USA.
authors.forename: Mirja
authors.initials: M
authors.lastname: Puolakkainen
authors.forename: Cho-Chou
authors.initials: CC
authors.lastname: Kuo
authors.forename: Lee Ann
authors.initials: LA
authors.lastname: Campbell
mesh_terms: D000469:Alkaline Phosphatase / Q000494:pharmacology; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002690:Chlamydia Infections / Q000276:immunology / Q000378:metabolism; D002692:Chlamydia trachomatis / Q000276:immunology / Q000378:metabolism / Q000472:pathogenicity; D023521:Chlamydophila Infections / Q000188:drug therapy / Q000276:immunology / Q000378:metabolism*; D016993:Chlamydophila pneumoniae / Q000187:drug effects / Q000276:immunology / Q000378:metabolism* / Q000472:pathogenicity; D042783:Endothelial Cells / Q000276:immunology / Q000378:metabolism / Q000382:microbiology*; D006241:Haptens / Q000276:immunology; D006801:Humans; D051379:Mice; D017527:Receptor, IGF Type 2 / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D006241:Haptens; D017527:Receptor, IGF Type 2; D000469:Alkaline Phosphatase