Abstract
Multinucleated giant cells were formed from bone marrow cells of rats during the long term culture on glass strips. These giant cells appeared in high number when the cells were cultured with a medium containing either fetal bovine serum (10% or 30%) or horse serum (30%), although these cells did not appear in cultures with the medium containing the rat serum. These giant cells began to appear first on 5th day, reach a maximum number about on 10th day and then decrease. These giant cells did not appear in 10-day-culture on human tooth slice. These giant cells were different from the isolated osteoclasts in such points as the positiveness of Fc and C3 receptor, the ineffectiveness to calcitonin, and the inability of bone resorption. These results show that the giant cells are distinct from osteoclasts. These giant cells were thought to be macrophage polykaryons, which were probably formed from macrophages of bone marrow during long contact with foreign body like a glass.
