Expression of CD19 and NK1.1 on cells produced in response to FL + IL-7 or FL + IL-7 + IL-10. A total of 1,000 Lin⁻Sca-1⁺c-kit⁺ cells was seeded in complete IMDM in FL + IL-7 (left panels) or FL + IL-7 + IL-10 (right panels). After 10 days of incubation at 37°C in 5% CO₂ , cells were analyzed for expression of CD19 (A + B) and NK1.1 (C + D) as described in the Materials and Methods. The histograms represent data from one of three independent experiments with similar results. Gray lines show irrelevant control antibody staining, whereas black lines represent the binding of specific antibodies. For all panels, the x-axis represents relative logarithmic fluorescence intensity, and the y-axis represents relative cell number.