Vaccine PGE₂ DCs induce antigen-specific effector CD8⁺ T cells. Naive CD45RA⁺CD8⁺ T cells specific for gp100:280-288 (50 000 per well) were cocultured with autologous cDCs, TLR DCs, TLR PGE₂ DCs, vaccine DCs, or vaccine PGE₂ DCs (7000 per well) that were loaded with either gp100:280-288 or an irrelevant peptide. After 16 hours, antigen-specific activation of CD8⁺ T cells was analyzed by measurement of CD69 surface expression (A) and secretion of IFN-γ in the supernatant (B). T-cell proliferation was analyzed by ³H-thymidine incorporation after 4 days (C). Granzyme B expression was measured by intracellular FACS staining after 5 days (D). Antigen-specific degranulation was measured by CD107a surface expression on gp100;280 TCR-expressing PBLs cocultured for 5 hours with differently matured DCs in the presence of Golgi-stop and PE-Cy5–labeled anti-CD107a (E). represents DCs loaded with specific peptide (gp100:280-288); and represents DCs loaded with irrelevant peptide. (A-B,D) Mean ± SEM values of the relative mean fluorescence intensity (A,D) or relative IFN-γ production (B) compared with cDCs of 3 (B) or 4 (A,D) independent experiments performed with cells from different donors; 100% corresponds to 40% ± 27% CD69-positive cells (A), 834 ± 697 pg/mL IFN-γ (B), and a mean fluorescence intensity of 238 ± 363 (D). Panel C shows mean ± SEM of 1 representative experiment of 4 performed. (E) Mean ± SEM values of the percentage of cells expressing CD107a. *P < .05. **P < .01. ***P < .001.