IgE alone stimulates the adhesion of BMMCs to FN via an increase in the avidity of VLA-5. (A) Adhesion of normal BMMCs to FN in response to assay medium alone (C), 1 μg/mL IgE, or 5 ng/mL SF in the absence (□) or presence of 400 μg/mL RGD-containing peptide (▪)or400 μg/mL control RGE-containing peptide (▨) for 15 minutes. Adhesion in response to IgE and IgE + RGE peptide, but not IgE + RGD peptide, was significantly (P < .05) different from control values. (B) Adhesion of BMMCs to FN in response to assay medium alone (C), 0.5 μg/mL IgE, or 5 ng/mL SF for 15 minutes in the absence (□) or presence (▪)of40 μg/mL anti-CD49e added 30 minutes prior to stimulation. Adhesion was significantly (P < .05) different between control (C) and all stimulated samples as well as between stimulated and stimulated + anti-CD49e–treated samples. Results shown are the mean ± SEM of triplicate determinations and similar results were obtained in 3 (A) and 3 (B) separate experiments. BMMCs were incubated on (C) BSA for 1 hour or (D) BSA for 4 hours (top panel) or on FN for 4 hours (bottom panel) in the absence (solid line) or presence (dashed line) of 2 μg/mL IgE. The cells were then stained with anti-CD49e antibody (1 μg/5 × 105 cells) for 30 minutes at 4°C and analyzed by FACS. The blackened area profiles were obtained with isotype control antibody.
