Research Article

Internalization of B Cell Receptors in Human EU12 μHC+ Immature B Cells Specifically Alters Downstream Signaling Events

Figure 5

Internalization of BCR changes downstream signaling events upon restimulation. EU12 μHC+, Daudi, and Ramos cells were directly stimulated with Cy5 labeled anti-IgM antibodies (10 μg/mL) for 3 min or pretreated with goat anti-IgM antibody F(ab′)2 fragments (2 μg/mL) for 30 min, washed, recovered for 4 h, and restimulated with Cy5 labeled anti-IgM antibodies (10 μg/mL) for 3 min. Fixed and permeabilized cells were analyzed by immunofluorescence microscopy for phosphorylated SYK (a) and ERK1/2 (b). Scale bar, 10 μm. Results shown are representatives from three independent experiments with more than 150 cells analyzed.