Phagocytosis and allogeneic T cell stimulation by cultured human osteoblast-like cells.

Background/aims: The antigen phenotype of human osteoblast-like cells suggests that they are related to other cellular populations and may also have immunologic functions in common.

Methods: Flow cytometry and transmission electron microscopy were used to show the phagocytotic activity of osteoblast-like cells in culture. The allogeneic stimulation of T cells by human osteoblast-like cells was determined by the measurement of T cell proliferation.

Results: We demonstrated in vitro that human osteoblast-like cells isolated from normal bone specimens obtained during mandibular osteotomy can phagocytose particles of different nature and size and can stimulate allogeneic T cells. Phagocytosis of microorganisms (E.coli, Klebsiella or C. albicans) was observed, although at a very low rate of activity in comparison with the phagocytosis of latex particles.

Conclusion: Our results suggest that human osteoblast-like cells may perform immunologic functions and act as antigen presentation cells.