Induction of beta2 integrin-dependent neutrophil adhesion to human alveolar epithelial cells by type 1 Streptococcus pneumoniae and derived soluble factors.
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.
Smith
J D
JD
Department of Paediatrics, University of Sheffield, United Kingdom.
Cortes
N J
NJ
Evans
G S
GS
Read
R C
RC
Finn
A
A
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
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