Fig. 4.
Engagement of CD22 with epratuzumab directly stimulates CD22 Tyr822 phosphorylation in HD B cells assessed by flow cytometry. PBMC from HD were incubated over time with epratuzumab (a; n = 7) or anti-IgM/IgG (b; n = 8), fixed and permeabilised and stained with B cell subset markers and anti-CD22 Tyr822. Data show CD22 Tyr822 signal on CD20+/CD27- naïve B cells (grey symbols) and CD20+/CD27+ memory B cells (blue symbols). MFI = mean fluorescence intensity after subtraction of time zero values