title: Induction of beta2 integrin-dependent neutrophil adhesion to human alveolar epithelial cells by type 1 Streptococcus pneumoniae and derived soluble factors.
abstract: Pneumonia caused by Streptococcus pneumoniae is characterized by neutrophil infiltration and variable epithelial injury. Neutrophil adhesion to alveolar epithelial pneumocytes (A549) was measured and demonstrated to be dose-dependent following preincubation of these (A549) pneumocytes with type 1 S. pneumoniae. Adhesion peaked at a bacteria-to-epithelial cell ratio of 5:1 after a 4-h incubation but was absent after 2 h and without FMLP. Filtered conditioned media (CM) from pneumococci cultured with (CM+) or without (CM-) epithelial cells were tested. CM+ induced significant adhesion in the absence of FMLP (P < .001); CM- had no effect. In the presence of FMLP, adhesion induced by both media was significantly greater than by FMLP alone (P < .001) and was significantly blocked (P < .01) by antibodies to CD11b and CD18. CM+ upregulated epithelial intercellular adhesion molecule 1 but CM- did not. These data provide new information concerning the interactions of S. pneumoniae, alveolar epithelial cells, and neutrophils.
authors.affiliation: Department of Paediatrics, University of Sheffield, United Kingdom.
authors.forename: J D
authors.initials: JD
authors.lastname: Smith
authors.forename: N J
authors.initials: NJ
authors.lastname: Cortes
authors.forename: G S
authors.initials: GS
authors.lastname: Evans
authors.forename: R C
authors.initials: RC
authors.lastname: Read
authors.forename: A
authors.initials: A
authors.lastname: Finn
mesh_terms: D000469:Alkaline Phosphatase / Q000032:analysis / Q000378:metabolism; D019138:Antibodies, Blocking / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000276:immunology; D018845:CD11 Antigens / Q000276:immunology; D018821:CD18 Antigens / Q000276:immunology; D002448:Cell Adhesion / Q000276:immunology*; D002478:Cells, Cultured; D017077:Culture Media, Conditioned / Q000494:pharmacology; D004847:Epithelial Cells; D004848:Epithelium / Q000276:immunology / Q000473:pathology; D005434:Flow Cytometry; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000276:immunology / Q000378:metabolism; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000276:immunology*; D011018:Pneumonia, Pneumococcal / Q000276:immunology*; D013296:Streptococcus pneumoniae / Q000276:immunology*; D015854:Up-Regulation
chemical_list: D019138:Antibodies, Blocking; D000911:Antibodies, Monoclonal; D018845:CD11 Antigens; D018821:CD18 Antigens; D017077:Culture Media, Conditioned; D018799:Intercellular Adhesion Molecule-1; D009240:N-Formylmethionine Leucyl-Phenylalanine; D000469:Alkaline Phosphatase