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Fig. 5. Characterisation of the VEGFR-1/
5ß1 integrin interaction. (A)
Dose-dependent VEGFR-1 binding to purified
5ß1-coated wells.
Different concentrations (10-1-104 ng/ml) of VEGFR-1/Fc
were added to
5ß1 coated wells (1 µg/ml) and bound molecules
were detected using an anti-human IgG (Fc specific)-alkaline phosphatase
conjugated antibody. Results represent the mean absorbance value of medium
from triplicate wells ± s.e.m. (B) VEGFR-1/Fc and VEGFR-2/Fc (20
µg/ml) were added to
5ß1-coated wells. In competition
experiments, EDTA (1 mM) or a blocking anti-
5ß1 antibody (10
µg/ml) was added during the assay. Absorbance resulting from non-specific
cell adhesion was measured on BSA-coated wells. Histograms represent the mean
absorbance value of medium from triplicate wells ± s.e.m. (C) Effect of
RGD peptides or VEGFR-1 growth factor ligands on cell attachment. Cells were
pretreated with 0.4 mM of RGD or RGE peptides, before plating on fibronectin
(FN) or VEGFR-1/Fc (5 µg/ml), or the adhesion assays were performed in the
presence of 20 µg/ml VEGF and placenta growth factor (PlGF). Results are
expressed as the percentage of adherent cells compared to untreated
controls.