Histological evaluation of three new monoclonal anti-cytokeratin antibodies. 1. Normal tissues.

Three new monoclonal anti-cytokeratin antibodies (mabs) potentially useful in cancer research and clinical diagnosis have been evaluated in immuno-histochemistry on cryostat sections of a broad variety of normal human tissues. A45-B/B3 reacts with all cells containing cytokeratins (epithelia and mesothelia). This mab positively identifies epithelial cells of any kind, and it may serve in differentiating carcinomas from tumours of mesenchymal origin. A53-B/A2 recognizes an individual cytokeratin, No. 19, and stains preferably mesothelia, urothelium, and bile duct epithelium. This antibody is suited to discriminate between different epithelial lineages. A51-B/H4 reacts with a subgroup of cytokeratins (probably including Nos. 14, 8 and/or 18). It is positive with most epithelia but negative with keratanized stratified epithelium. This antibody shows an interesting, but up to now unexplained, cross-reactivity with nuclei of certain nonepithelial cells. All three mabs also react with epithelial cells from at least three animal species.