Phagocytosis and membrane fluidity: application to the evaluation of opsonizing properties of fibronectin.
The uptake of particles by phagocytic cells involves an increase in the membrane fluidity determined by steady-state fluorescence polarization. Binding and endocytosis of target particles is in vivo enhanced by humoral factors called opsonins. In this work, fluorescence polarization was used to detect in vitro the opsonic activity of a plasma protein: fibronectin. The assay is based on the analysis of membrane fluidity variations following the uptake of gelatinized latex beads by phagocytic cells in the presence or in the absence of fibronectin. Using TMA-DPH as fluorescent probe, it was observed that the increase in membrane fluidity was enhanced in presence of fibronectin and depended upon the enhanced in presence of fibronectin and depended upon the opsonic activity was related to the integrity of the molecule. Using this method, the opsonic activity of various plasmas could be also determined.
Muller
S
S
INSERM U 284, Vandoeuvre Les Nancy, France.
Masson
V
V
Droesch
S
S
Donner
M
M
Stoltz
J F
JF
D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D004161:Diphenylhexatriene / Q000031:analogs & derivatives; D005353:Fibronectins / Q000502:physiology*; D005454:Fluorescence Polarization; D005456:Fluorescent Dyes; D005780:Gelatin / Q000378:metabolism; D006801:Humans; D007840:Latex; D008264:Macrophages / Q000378:metabolism; D008560:Membrane Fluidity / Q000502:physiology*; D008863:Microspheres; D009504:Neutrophils / Q000378:metabolism; D009895:Opsonin Proteins; D010587:Phagocytosis / Q000502:physiology*
D005353:Fibronectins; D005456:Fluorescent Dyes; D007840:Latex; D009895:Opsonin Proteins; D004161:Diphenylhexatriene; C033628:1-(4-(trimethylamino)phenyl)-6-phenylhexa-1,3,5-triene; D005780:Gelatin