Figure 2.

MSCs differentially express CTLA-4 protein with regard to oxygen availability. (A) Representative histogram of CTLA-4 surface expression on human bone marrow-derived MSCs and surface CTLA-4 staining of human MSCs as analyzed by flow cytometry. (B) Fluorescence intensities are depicted as box plots of delta of geometric means normalized to an antibody block (n = 5; * p < 0.05; paired t-test). (C,D) Intracellular CTLA-4 expression and secretion by human MSCs was confirmed by immunoblotting after native PAGE and ELISA. (C) Intracellular fl/sCTLA-4 (n = 4; * p < 0.05; paired t-test) and (D) secreted sCTLA-4 was enhanced in MSCs cultured under hypoxic conditions (Hox; 1% O₂) as compared to normoxic conditions (Nox; 18% O₂) (n = 6; * p < 0.05; paired t-test).