Figure 1.

IFN-α production is impaired in CpG type A-activated aged pDCs compared to young pDCs in vitro and to systemic administration of CpG type A in vivo. A-B, The pDCs were isolated from the bone marrow of young and aged C57BL/6 mice and incubated for 18h with CpG-ODN at 5 or 10 μg/ml. IFN-α (A) and IL-12p40 (B) production was measured. Control cells were stimulated with either PBS or DOTAP. C, Aged pDCs exhibited defective IFN-α in dose response experiments at 24h post CpG stimulation. IL-12p40 responses were preserved in dose response experiments in aged pDCs as compared to young counterparts (data not shown). D, IFN-α responses by aged pDCs were inferior to young pDCs in time course experiments. *p<0.05 (Student's t-test). The results in A-D are representative of at least four independent experiments with similar findings. N=3 per group for each experiment. E-F, Young and aged C57BL/6 mice were administered type A CpG i.v., and then serum IFN-α (E) and IL-12p40 (F) levels were assessed by ELISA. ***p<0.0001. The results are representative of at least three independent experiments with similar results. N=3 per group for each experiment.