Idiotype nonspecificity of LP-1–specific CTLs.

DCs were generated from adherent PBMNCs of an HLA-A3/24, B44/60, Cw3/5 buffy coat in RP-10 medium supplemented with GM-CSF and IL-4. On days 1 and 5, the isolated idiotype of the LP-1 cells was given to the culture at a final concentration of 50 μg/mL, before the addition of TNF-α on day 6. After a culture period of 7 days, the Id-pulsed DCs as well as LP-1 myeloma cells and natural killer (NK)–sensitive K562 cells were used as targets in a ⁵¹Cr-release assay. Autologous DCs were transfected with LP-1 total RNA or control RNA (EGFP IVT) on day 6 by electroporation and used on day 7 as additional control.