FIG. 6.

Recombinant A27L protein binds to the cell surface. Live BSC40 cells were incubated at 4°C for 30 min with PBS (A and F) or biotinylated A27L protein alone (B and G) or A27L protein previously mixed with heparin (C and H), condrointin sulfate (D and I), or dermatan sulfate (E and J) as described in Materials and Methods. The cells were washed three times and phycoerythrin-conjugated streptavidin was added for another 30-min incubation. After being washed, the cells were observed with a fluorescence microscope (A to E) or reverse-phase light microscope (F to J). All the images were analyzed as described in Materials and Methods.