FACS analysis of labelled cells. (A) MNC were gated (R1) and dead cells excluded by PI labelling (R2 not shown). A total of 50,000 events was aquired from each tube. (B) The number of CD14⁻ and CD19⁻ events occuring with the negative control antibody was measured (R1 and R3). Two negative control tubes were analyzed, and the mean of these two values (eg, 0.04% in the example shown) was used. (C) Events in R1 and R3 (CMRF44⁺ CD14⁻ and CD19⁻cells) were counted in three separate tubes. The mean negative control value (B) was subtracted from each value. The mean of these three replicates was used as the DC percentage of MNC. The absolute DC count was calculated as described in the Results.