Effect of MARCO knock-down on DC morphology following LPS activation. (A) MARCO mRNA quantification by real-time PCR in LPS-activated D1 cells, treated with the indicated amounts of MARCO GeneBlock (GB). The average MARCO-actin ratio is the quotient of the fluorescent signal obtained from the MARCO mRNA amplification with a specific TaqMan ampliconset for MARCO divided by the value of the fluorescent signal obtained from the actin mRNA amplification with the TaqMan ampliconset for actin. These values are taken from a point where the amplification is in a linear range. The average is taken from triplicates. GBC indicates control GeneBlock. The percent knock-down is obtained by setting the value of average MARCO-actin ratio (AMAR) obtained with the GBC as 100% and calculating the remaining value of the GB-treated sample in relation to that of GBC. Double staining for filamentous actin (B-C) and MARCO (D-E) of D1 cells after treatment with anti-MARCO (GB anti-MARCO) and control (GBC) GeneBlocks cells were treated with GeneBlocks for 48 hours and activated with LPS during the last 24 hours. Knock-down of MARCO in D1 cells inhibits the progression toward the terminal maturation stage, and many cells show a morphology typical of transitional cells. Original magnifications, × 400. (F) Percentage of polarized or lengthened cells counted in randomly selected fields. The experiment was repeated twice with similar results. Error bars in panels A and F represent standard deviations from the mean calculated on the randomly selected fields.