The peroxidase antiperoxidase staining of factor VIII-related antigen on cultured endothelial cells.

To prevent the premature occlusion of vascular prostheses, endothelium is being cultured experimentally onto synthetic flow surfaces. A rapid method of identifying cultured endothelium on the prosthesis is valuable for determining the degree of fibroblast and smooth muscle cell contamination and to screen for endothelial cell transformation. Fluorescent Factor VIII related antigen (FVIII-RA) staining has been used to identify cultured endothelium, but results in excessive staining of the underlying prosthesis, loss of morphologic detail, and deterioration of the FVIII-RA antibody reaction with time. We have applied the peroxidase antiperoxidase (PAP) method of antigen staining to permit staining of FVIII-RA and thereby to permit a sensitive and specific identification of human or canine endothelium with a concurrent analysis of morphologic detail.