Real-time kinetic analysis of calcium influx in B220^– and B220⁺ T lymphocytes stimulated with ATP.

<p>Spleen cells from 4-mo-old MRL<i>^+/+</i> (<i>red</i>) MRL/<i>lpr</i> (<i>blue</i>) and B6<i>^P2X7−/−</i> (<i>black</i>) mice (n = 3 mice/group) were loaded with calcium-reactive fluorescence probe, Oregon Green 488 BAPTA-1. After loading, cells were stained with anti-CD90, anti-CD19 and anti-B220 mAbs. Baseline MFI of the calcium probe was recorded in the gated B220^–CD90⁺ (○) and B220⁺CD90⁺ (▵) T cells during 50 s by flow cytometry, and was followed by the addition of 500 µM ATP (at time t0, arrow). Changes over time in MFI values of the calcium probe were monitored in the T-cell subsets by flow cytometry. MFI values were normalized by subtracting the baseline MFI.