Induction of CTL responses by peptide-pulsed DC. Adherent PBMNC were grown for 7 days in RP10 medium supplemented with GM-CSF, IL-4, and TNF-. DC pulsed with the synthetic peptides derived from the MUC1 protein (M1.1 and M1.2) were used to induce a CTL response in vitro. In addition to the MUC1 peptide DC were incubated with the Pan-DR binding peptide PADRE as a T-helper epitope. Cytotoxic activity of induced CTL was determined in a standard ⁵¹Cr-release assay using T2 cells as targets pulsed for 2 hours with 50 μg of the cognate (open symbols) or irrelevant Her-2/neu protein-derived E75 peptide (solid symbols).