Incorporation of cellular material derived from unmodified lymphoma cells or from trioma cells by DC. A20 (a) or BiV cells (b) were labelled with CFDA and coincubated for 1 hour with iDC at 4°C or 37°C. CFDA fluorescence of viable, CD11c and MHC class II double-positive DC was measured by flow cytometry. Typical result from 5 experiments using BiV and 3 experiments using A20 cells. The average uptake of A20 cells was 1.5-fold increased at 37°C in comparison to 4°C (standard deviation = 0.2), the internalization of BiV cells was increased 8.5-fold in an average (s = 1.2).