Tumor lysate stimulates DC maturation and activation. (A) Surface expression of CD1a, CD40, CD80, CD83, and CD86, known DC and activation markers, is shown after exposure of monocyte-derived DCs to tumor lysate. This maturation and activation was partially blocked by coating of monocyte-derived DCs with anti-CD91. There were no statistically significant differences in phenotypic markers of KS and non-KS monocyte-derived DCs. (B) Surface expression of CD91 before and after the addition of tumor lysate was compatible with the presence of HSPs in the preparation. Percentages indicate percentage of cells in the upper right quadrant of each plot.