CCL-21 protein production by AdCCL-21-DC. DC propagated in vitro with GM-CSF and IL-4 were transduced with human AdCCL-21 or AdCV on day 6 of culture at MOIs 50:1 and 100:1. Transduction was accomplished by the standard incubation at 37°C (a) or by the centrifugation method (b) as described in materials and methods. CCL-21 protein concentration was determined in the supernatant of AdCCL-21 DC, AdCV-DC and NTDC by ELISA 48 hours after transduction. A 2.9 fold increase in CCL-21 protein production was achieved by the centrifugation method of DC transduction compared to the standard method. Values refer to CCL-21 protein concentration expressed in nanograms per million cells and are representative of three independent experiments. P values refer to significant differences of AdCCL-21-DC with AdCV-DC and control DC.