Defensin stimulates the binding of¹²⁵I-apo(a) to HUVEC matrix and to fibronectin. Complexes composed of 5 μmol/L defensin/20 nmol/L ¹²⁵I-apo(a) were incubated with HUVEC matrices (A) or well coated with 5 μg/mL fibronectin (C) for 1 hour at 37°C alone or in the presence of 100 mmol/L EACA or 2 U/mL heparin, and the bound radioactivity was determined and expressed as described above. The binding of¹²⁵I-Lp(a)/defensin complexes to cell matrix (B) and to fibronectin (D) was performed under the same conditions as described above. The mean ± SD of 3 experiments performed in triplicate is shown.