Figure 4.

Comparison of DC uptake of γ-irradiated CLL cells (nonapoptotic, as determined by intact mitochondrial integrity using NAO staining) and UV-irradiated CLL cells (>98% apoptotic, as determined by reduced NAO staining). (A) Efficient uptake of γ-irradiated CLL cells by αDC1. (B) Comparable uptake of γ-irradiated CLL cells by αDC1 and sDCs. In all cases, DCs were loaded with CSFE-labeled UV- or γ-irradiated CLL cells at a ratio of 2:1. CLL cells were added to DC cultures 2 h after the addition of the maturation-inducing cytokines on Day 6. Mature DCs, identified by HLA-DR (A) or CD11c expression (B) were harvested on Day 8 and tested for the uptake of CFSE-positive tumor material by flow cytometry.