Phosphatidyl choline-mediated inhibition of Streptococcus pneumoniae adherence to type II pneumocytes in vitro.
Nearly 80% of the adherence of several strains of Streptococcus pneumoniae to A549 lung cells was inhibited by dimyristoylphosphatidylcholine (DMPC), as well as by the following mixtures of lipids: DMPC/globoside, DMPC/asialo GM-1 and DMPC/asialo GM-1/globoside liposomes. Control phosphatidylserine liposomes were ineffective at inhibiting bacterial adherence demonstrating the specificity of the interaction between bacteria and liposomes. FITC-labelled bacteria were shown to adhere directly to silica beads coated with DMPC. The proportion of S. pneumoniae bacteria binding to DMPC-coated beads did not exceed 20% of the bacterial population as shown by the binding isotherm. This clearly demonstrates that only a fraction of the bacterial population (a subpopulation) was capable of binding to the beads. The specificity of bacterial binding to DMPC was further demonstrated by surface plasmon resonance. By this latter technique, the affinity between DMPC and bacteria was shown to be high and substantially non-reversible. Finally, we established that in order to be efficient at inhibiting bacterial binding to A549 cells the average liposome diameter must be greater than approximately 200 nm suggesting that a multivalent attachment of the bacterium to a liposome is required for high affinity binding.
Bérubé
L R
LR
Institute for Biological Sciences, National Research Council Canada, 100 Sussex Dr., Ottawa, Ontario, K1A 0R6, Canada.
Schur
M K
MK
Latta
R K
RK
Hirama
T
T
McKenzie
C R
CR
Jarrell
H C
HC
D001422:Bacterial Adhesion / Q000187:drug effects*; D004134:Dimyristoylphosphatidylcholine / Q000494:pharmacology*; D006017:Glycolipids / Q000494:pharmacology; D006801:Humans; D008081:Liposomes / Q000494:pharmacology; D008168:Lung / Q000166:cytology / Q000187:drug effects / Q000382:microbiology / Q000502:physiology*; D008855:Microscopy, Electron, Scanning; D008856:Microscopy, Fluorescence; D008863:Microspheres; D010718:Phosphatidylserines / Q000494:pharmacology; D013296:Streptococcus pneumoniae / Q000502:physiology*; D020349:Surface Plasmon Resonance; D014407:Tumor Cells, Cultured
D006017:Glycolipids; D008081:Liposomes; D010718:Phosphatidylserines; D004134:Dimyristoylphosphatidylcholine