Human Myeloma Cell Lines Induce Osteoblast Downregulation of CD99 Which Is Involved in Osteoblast Formation and Activity

Figure 4

CD99 agonist monoclonal antibody increases Alkaline Phosphatase (ALP) activity and Collagen I (COLLI) expression in normal human osteoblasts (hOBs). (a) Histochemical staining for ALP in differentiated normal hOBs treated for 6 days with or without anti-CD99 agonist monoclonal antibody or mouse IgG. This experiment has been performed in triplicate. The histograms represent the number of ALP positive cells respect to total cells ± SE in three different fields (10x), of three independent experiments. (b) hOBs, treated with anti-CD99 agonist monoclonal antibody or with mouse IgG for 0, 4, and 6 hours (h), were lysed and analyzed by western blot analysis to detect the protein levels of COLLI. The histograms represent the mean optical density (OD) of COLLI ratio normalized to the OD of -Actin. Data are presented as mean ± SE. The figure shows one of three independent experiments.

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