Peripheral blood lymphocyte binding to a soluble FITC-fibronectin conjugate

Fibronectin receptors are critical to lymphocyte-mediated inflammation, and binding between immobilised plasma fibronectin and peripheral blood lymphocytes (pbl) is enhanced in patients with inflammatory diseases. Such enhancement could be due to an overall increase in receptor capacity and/or be a feature of a subset of cells. It could also depend on the initial binding and/or on events that follow receptor occupancy (e.g., cell spreading). To address these questions, we used fluorescein isothiocyanate-conjugated soluble fibronectin (FITC-FN) in a flow cytometric assay of lymphocyte-fibronectin binding. EDTA-inhibitable adhesiveness to FITC-FN is enhanced in lymphocytes cultured with Interleukin 2 and in fresh peripheral blood lymphocytes (pbl) from untreated patients with acute exacerbations of chronic inflammatory diseases. The enhanced binding was noted on both CD4+ and CD8+ subsets, and decreased with anti-inflammatory therapy.