Immunofluorescence studies of human cellubrevin in platelets. Platelets were fixed with 3.7% formaldehyde and permeabilized with 100 μg/mL digitonin. The cells were then incubated with (A) anti-Hceb antibody (1/5) followed by FITC-conjugated antirabbit antibody (1/150); (B) anti-Hceb antibody that had been preincubated with 200 μg of GST-Hceb recombinant protein followed by FITC-conjugated antirabbit antibody (1/150); (C) anti-Hceb antibody that had been preincubated with 200 μg of GST-VAMP 2 recombinant protein followed by FITC-conjugated antirabbit antibody (1/150). A DIC image of each panel is included below. Original magnification 2,800×.