Bone marrow mononuclear cells were tested for kit and VLA4 expression after three daily injections of anti-VLA4. Labeling of cells with 2° antibody only, or anti-VLA4 and 2° antibody, gave superimposable profiles (not shown) indicating that cells were saturated by anti-VLA4 in vivo. Scattergram on the left panel was identical when untreated or treated animals were tested and the insert depicts cells in blast window analyzed for both kit expression (using directly conjugated anti-kit) and VLA4 expression. Note that after anti-VLA4 treatment both kit and VLA4 expression are downmodulated (middle and right panel). Downmodulation of kit was similar in two other experiments comparing untreated and treated bone marrow cells.