INTERFERON-GAMMA AND TUMOR-NECROSIS-FACTOR-ALPHA PROMOTE THE BINDING OF DENDRITIC CELLS TO FIBRONECTIN

Connective tissue dendritic accessory cells (DC) accumulate at sites of extracellular matrix (ECM) deposition. The adherence of DC to purified ECM proteins was examined. Splenic and pulmonary DC were purified from Lewis rats and incubated on slides coated with fibronectin (FN), laminin (LN), or collagen (COLL) types I, III and IV. In other experiments, DC were pre-incubated with selected proinflammatory cytokines (IL-1, IL-2, IFN-gamma), TNF-alpha in order to determine their abilities to modulate cell adherence to ECM. Both splenic and pulmonary DC showed dose-dependent binding to FN that was inhibited by the synthetic peptide arg-gly-asp-ser. There was minimal DC binding to LN or COLL. Pretreating DC with IFN-gamma or TNF-alpha enhanced DC binding to FN but did not increase binding to LN or COLL. IL-1 and IL-2 had no demonstrable effect on DC binding to ECM. Our results suggest that FN is a critical ligand for DC in their binding to the ECM. IFN-gamma and TNF-alpha increase adherence of DC to FN and may promote their accumulation in the lung during inflammation.