The role of adhesion molecules in cultured human osteoblasts (OB) and osteoclasts (OC) in bone destruction was studied. OB and OC were obtained from human periosteum and human bone marrow. Adhesion molecules were quantified by cell ELISA using monoclonal antibodies (mab) . Ca release was estimated by 45Ca release assay.
In OC, both ICAM-1 and VCAM-1 were expressed and strongly enhanced by IL-1β, TNF-α and mildly by IL-6. LFA-1, Mac -1 and VLA-4 were also expressed and enhanced by IL-1β and TNF-α. In OB, both ICAM-1 and VCAM-1 were highly expressed. OC strongly adhered to IL-1β-stimulated OB, and released Ca from OB. ICAM-1 mab did not abolish the adhesion and Ca release. The results obtained suggest that OB-OC cell interaction and OC-matrix interaction play important roles in OC-mediated bone resorption and that not only ICAM-1/LFA-1 (Mac -1) adhesion pathway but also other adhesion pathways mediate cell-cell or cell-matrix interaction in bone.
