CD43 clusters at the uropod of polarized TILs and colocalizes with moesin. (i) TILs were allowed to adhere to coverslips coated with FN80. Then, single (A and B) or double (C and D) immunostainings were performed as described under the Materials and Methods. (A and C) Staining with the anti-CD43 HP2/21 MoAb. (B and D) Staining with the antimoesin 38/87 MoAb. Arrows point to cellular uropods. (ii) TILs were cocultured on a monolayer of autologous melanoma cells for 1 hour at 37°C. Fixed cells were then stained with the anti-CD43 TP1/36 MoAb (A). In (B), the same field was photographed under bright field conditions. Note in (A) the typical migratory morphology of the TIL on melanoma cell (MC), showing the frontal leading edge (L) and the trailing uropod (U).