Fig. 7. The pH dependence of dextran trafficking. Osteoclasts were plated on dentine disks and incubated for 16 hours before a 30 minute pre-incubation with 25 nM bafilomycin A1 or vehicle control. TRITC-labelled dextran-3000 was then added for 5 minutes before fixation and immunodecoration with antibodies against the _vß₃ integrin. Representative single CSLM sections for cells treated with the vehicle control (A) or bafilomycin A1 (B) are shown; the outline of the cells as delineated by _vß₃ antibodies is depicted by a dashed white line. Scale bar, 10 µm. The number of osteoclasts presenting endocytosed dextran was counted and expressed as the percentage of endocytosis inhibition ± s.e.m. (Table).