Leukocyte Mobilization from Bone Marrow: Effect of the RGD-Containing Peptides of C3 and Fibronectin

A peptide derived from complement component C3 caused leukocyte release in a perfused rat femur model. The function was related to the complement receptor 3 (CR3)-binding region in the α-chain of human C3. The peptide spanning this region contained RGD, a known ligand mediating cell-cell and cell-matrix interactions. We present data that also RGD and RGDS released leukocytes. Moreover the 120 kD RGD-containing fragment of fibronectin and monoclonal antibodies to its receptor α5β1 induced a massive leukocyte release. Leukocyte detachment from the marrow is mediated by interference with RGD-peptides of C3 and fibronectin.