Proliferation of T cells cocultured with Ig-pulsed autologous DCs. Immature DCs were pulsed with autologous mIg from sera of patients with progressing MM (auto-mIg MM; 9 patients). DCs were subsequently subjected to differentiation in the presence of TNF-α for 2 days and irradiated prior to coculture with autologous PBMCs labeled with CFSE at a ratio of 1:10 (DC/PBMC). Cells were harvested after 7 days of culture for FACS analysis of surface T-cell markers and intracellular concentration of CFSE (Figure 1). mIg preparations from patients were also used for pulsing of DCs derived from healthy subjects prior to cultures with CFSE-labeled PBMCs (allo-mIg Ctrls; mean values of 8 different mIgs are shown). Alternatively, autologous polyclonal Ig (auto-Ig Ctrls; 4 control donors) were used for pulsing of DCs derived from the respective healthy subject prior to cultures with autologous CFSE-labeled PBMCs. The mean percentages plus or minus SD (left graph) and mean total cell numbers/culture plus or minus SD (right graph) of CD4⁺ and CD8⁺ T cells that had proliferated during culture (CFSE-low) of representative experiments are depicted. Significant differences (**P < .01; *P < .05; t test) versus the CD4⁺ T-cell response to auto-mIg pulsed DCs of patients with MM (auto-mIg MM) are indicated.