DC generation in steady-state and dynamic conditions. In vivo administration of RAPA suppresses DC generation under (A) steady-state and (B-C) dynamic conditions and inhibits up-regulation of costimulatory molecules. (A-C) Effect of RAPA or drug vehicle on the number of CD11c⁺ DCs/tissue on day 10 (with or without Flt3L). Results are representative of 8 to 10 animals/treatment group. **P = .005 versus vehicle (A, normal spleen), P = .003 versus vehicle (B, Flt3L bone marrow), P = .002 versus vehicle (C, Flt3L spleen); 2-tailed Student t test. Bars indicate 95% confidence interval and mean (rectangle). (D-E) Effect of RAPA or drug vehicle on spleen weight and appearance (8 animals/treatment group) in Flt3L-treated animals on day 10. **P = .0004 versus vehicle, 2-tailed Student t test. Bars indicate 95% confidence interval and mean (rectangle). (F-G) Effect of in vivo RAPA or drug vehicle administration on costimulatory and MHC class II molecule up-regulation after ex vivo LPS stimulation. Cells were gated on CD11c. The median fluorescence intensity (MFI) (F) and relative MFI (G) of CD11c⁺ cells expressing the antigen of interest in comparison with cells from drug vehicle-treated control animals is indicated. (F) Typical data from one representative experiment on day 10 after start of treatment. (G) Each point represents a single experiment with 3 to 6 animals (with or without Flt3L) per treatment group after in vivo administration of RAPA (7-10 days) or vehicle. **P < .01 versus vehicle (Wilcoxon test).