Figure 3.

DCs migration across a Caco-2 monolayer is reversible.

Caco-2 cells were grown on transwell filter to form a confluent monolayer then DCs were let to adhere to the bottom of the filter. Cell-free R5 HIV-1^AD8 or medium were incubated on the apical side of the Caco-2 monolayer for 2 h (Apical stimulus). After extensive wash, samples were either immediately fixed with 2% PFA, or the transwell moved in a new plate containing either medium or fractalkine (FRK, 100 ng/ml) in the basal chamber and further incubated for 3 h before fixation (Basal stimulus). Quantitative analysis of DCs migration across the Caco-2 cell monolayer at the apical (A) and medial (B) level of the cell layer is shown. Results are the mean of three replicates each and are expressed as percentage of the positive control (i.e. area occupied by DCs following apical treatment with HIV-1). n.d., not done.