Figure 5

S1P inhibition alters phenotypic maturation and prevents antibody secretion. (A) In vitro activated human B-cells were treated with 10 μM PF-429242 at day 3 and analyzed at 12 h intervals. Live cells were evaluated for surface phenotype. (B) The levels of CD38 expression in the lower left quadrant (CD38 low) or upper left quadrant (CD38 high) were determined for 7 donors at the 72 h time point. Data depict the mean ± standard deviation with significance determined by t-test (**P = 0.003, ***P = 0.001). (C) Day 3 human differentiated B-cells were treated with 10 μM PF-429242 or dH2O for 72 h. After the incubation, the cells were sorted based on CD38 (high and low). An equal number of sorted cells (2,000 cells) were used to quantify ASCs using ELISpot for IgM and IgG.