CCR7 up-regulation is dependent on ERK1/2 activation. (A) Ramos GFP (left panel) and Ramos GFP-ZAP-70 (right panel) cells were incubated for 1 hour in the presence of 50μM or 100μM PD98059 for ERK1/2 inhibition, and in the presence of 5μM or 10μM LY294002 for Akt inhibition before 5 minutes of stimulation with 5 μg/mL F(ab′)2 anti-IgM. Inhibition of phosphorylation of Akt and ERK1/2 was confirmed by immunoblotting. Jurkat cells treated with PV were used as positive control. (B) IgM stimulation was performed for 4 hours after 1 hour of preincubation with Akt and ERK1/2 inhibitors, and the levels of CCR7 were measured by flow cytometry. Inhibition of ERK1/2 phosphorylation with PD98059 significantly reduced the IgM-mediated induction of CCR7 expression, whereas inhibition of Akt had only a minor effect on CCR7 expression. *P < .05, versus the IgM activated cells. MFIR was calculated relative to unstimulated samples.
