Immunocytochemistry for PAR-1 in B16F10 cells transfected with S14 PAR-1, antisense A12, and mock plasmid. Cells were subcultured onto chamber slides, fixed, washed, and stained with a rabbit antirat PAR-1 Ab. PAR-1 binding was detected with a goat antirabbit biotinylated Ab, followed by avidin-biotin-HRP and appropriate chromagen. Cells were counterstained with hematoxylin. (A) Negative control with absence of primary Ab. (B) Wild-type B16F10. (C) Mock plasmid-transfected cells. (D) Antisense A12. (E and F) S14 cells. Note membrane (arrows) as well as intracytoplasmic positive brown staining of PAR-1. Original magnification × 1,500.