The effect of Tween 20 on indirect immunoperoxidase staining of blood group antigen A in human urothelium.

The effect of the nonionic detergent Tween 20 on background staining, sensitivity, and specificity in the indirect immunoperoxidase staining for blood group antigen A was investigated histologically and spectrophotometrically. Pretreatment of dewaxed formalin-fixed Paraplast-embedded tissue sections from human ureters with 2% Tween 20 and dilution of the first and second layer antisera with 0.05 or 2% Tween 20 significantly reduced background staining of the urothelial cell cytoplasm, ureteral stroma, and musculature. Spectrophotometrical analysis of tissue sections from hypernephroma (rich in cytoplasm), cervix (fibrous stroma), and myometrium (musculature) underlined the histological results with a significant reduction of the maximum absorbance of Tween 20-modified indirect immunoperoxidase-stained tissue sections. Sensitivity, evaluated histologically by the endpoint titers of urothelial cell membrane staining, endothelial cell staining, and focal cytoplasmic staining of urothelial cells, was not influenced by the Tween 20 treatment. The specificity was improved as the staining was highly reduced or absent in control sections subjected to Tween 20.