Figure 6.

Phosphatases in Um B cells are more susceptible to inhibition by H₂O₂. PBMC were treated with 6 mM of H₂O₂ and phosphorylation of proteins associated with the BCR were measured in naïve and Um B cells (A and B) after 5 min of stimulation at 37°C. Displayed are overlaps of unstimulated (1% BSA) (red) and stimulated (H₂O₂ without anti-IgM) (purple) naïve B cells (A). Similar data display was used for Um B cells (B). Shown are percentages (red letter/numbers = negative controls; purple letter/numbers = H₂O₂ stimulation) as well as fold changes in mean fluorescence intensity (MFI) of stimulated compared to unstimulated cells. Um cells showed enhanced phosphorylation of Syk and p38MAPK (B), compared to naïve B cells (A). Akt phosphorylation was similar in both cell populations (A and B).