In vitro characterization of immune-related properties of human fetal bone cells for potential tissue engineering applications

We describe herein some immunological properties of human fetal bone cells recently tested for bone tissue engineering applications. Adult mesenchymal stem cells and adult osteoblasts were included in the study for comparison. Surface markers involved in bone metabolism and immune recognition were analyzed by flow cytometry before and after differentiation or treatment with cytokines. Immunomodulatory properties were studied on activated peripheral blood mononuclear cells (PBMCs). The immuno-profile of fetal bone cells was further investigated at the gene expression level. Fetal bone cells and adult mesenchymal stem cells were positive for Stro-1, ALP, CD10, CD44, CD54 and β2-microglobulin, but HLA-I and CD80 were less present than on adult osteoblasts. All cells were negative for HLA-II. Treatment with rhIFN-γ strongly increased the presence of HLA-I in adult cells, compared to fetal cells. In the presence of activated PBMCs, fetal cells had antiproliferative effects, although with patterns not always comparable to those of adult mesenchymal and osteoblast cells. Due to the immunological profile and with their more differentiated phenotype as compared to stem cells, fetal bone cells present an interesting potential for allogeneic cell source in tissue engineering application.