Figure 3.

Effect of aging on CCR7 expression and function. (A) Transwell migration of DCs in response to CCL21 was determined as described in Materials and Methods. Values represent the average of three independent experiments, each of them with at least 3 mice per group. (B) CCR7 cell surface expression on young and old tDCs. Cells were stained with PE-labeled anti-CCR7 mAb. A representative experiment is shown: open profiles show the background with isotype-matched control antibody; filled profiles show the fluorescence staining of CCR7. (C) Time-dependent tyrosine phosphorylation of young and old tDCs. Cells were treated with CCL21 for the times indicated and Western blot analysis was done using anti-phosphotyrosine antibody G410. The membranes were washed and reprobed with β-actin Ab to control for differences in gel loading. Relative density of the two most prominent bands in young and old DCs are indicated. The right panels show the band density relative to the value of the young sample with no CCL21 stimulation (arbitrarily defined as equal to 1). The tyrosine phosphorylation results shown are representative of three independent experiments.