FIG. 6.

Specificity of DraD-mediated binding for the α₅β₁ integrin receptor examined by IFM. Visualization of interactions between DraD-coated beads and HeLa cells in the presence or absence of the monoclonal α₅β₁ integrin antibodies. HeLa cells were incubated with polystyrene beads coated with BSA (as a negative control) or the native DraD, fixed, and subjected to microscopy. Extracellular polystyrene beads were labeled with rabbit anti-BSA or anti-DraD and visualized by the red fluorescence of TRITC-labeled anti-rabbit antibodies. IFM of polystyrene beads coated with BSA (negative control) (A and C) and DraD (B and D) incubated with HeLa cells in the presence (A and B) or absence (C and D) of monoclonal α₅β₁ integrin antibodies, respectively. Counting was performed on 50 cells associated with beads. The beads associated with other cells were too aggregated; thus, counting was not possible. Magnification, ×10,000 (Olympus BX-60 microscope).