Porphyromonas gingivalis induces ultrastructural and cytoskeletal changes in adherent human polymorphonuclear leucocytes.
The response of polymorphonuclear leucocytes (PMN) from healthy humans to culture supernatant from the periodontopathogen, Porphyromonas gingivalis, was examined using light, fluorescence and electron microscopy. Exposure of adherent cells to bacterial culture supernatant resulted in a 4-fold increase in the proportion of spread, flattened PMN. Scanning and transmission electron microscopy demonstrated that these cells had long dendritic cytoplasmic projections closely adherent to the substratum, in contrast with the more rounded, less adherent, control PMN. These shape changes were accompanied by a mean reduction in granule density to 57% compared with control cells (p<0.05) and a reduction in F-actin levels to 62% of controls (p<0.001), but no loss of viability and suggest a bacterially-induced mechanism of suppression of PMN motility which is likely to contribute to the pathogenic potential of P. gingivalis.
Scragg
M A
MA
Department of Oral Pathology, St. Bartholomew's and the Royal London School of Medicine and Dentistry, UK. m.a.scragg@mds.qmw.ac.uk
Kelly
M J
MJ
Williams
D M
DM
D000328:Adult; D016866:Bacteroidaceae Infections / Q000473:pathology*; D002448:Cell Adhesion; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000382:microbiology / Q000648:ultrastructure*; D006801:Humans; D008854:Microscopy, Electron; D018375:Neutrophil Activation; D009504:Neutrophils / Q000382:microbiology* / Q000648:ultrastructure*; D016966:Porphyromonas gingivalis