Expression of surface antigens by from freshly dissociated MGNTs cells and MGNT-derived cells forming spheres in culture. A. Control IgGs. B. Fresh tumors were dissociated enzymatically with trypsin and immediately immunolabeled with either CD133 (left panel) or CD34 (right panel). C. MGNT-derived cellular spheres were dissociated mechanically as described (see text), and immunolabeled. Cells were analyzed by flow cytometry and the positive gates indicated were defined based on analysis done after double labeling with FITC- or PE-labeled isotype-matched non-immune immunoglobulin and another specific antibody. Results are expressed in a morphological gate including all viable nucleated cells. Data shown are from one experiment out of three giving similar results.