Species Cross-Reacting Epithelial and Urothelial Specific Antigens in Human Fetal, Adult, and Neoplastic Bladder Epithelium 1

raised against the saline-soluble fraction of homogenates of calf urinary bladder epithelium. After absorption with human red blood cells, human, calf, and mouse sera, and noneplthellal organs, this antiserum was specific for all human epithelia tested. Further absorptions with nonurlnary tract epithelia rendered the antiserum specific for urothellum. Species cross-reactivity was seen between the superficial cell layers of calf, human fetal, and adult bladder epithelia. The antigen appeared to be cytoplasmic and was also present (although to a lesser extent) In human bladder tumor biopsy specimens and human bladder tumor cell IInes.-JNCI 63: 1322-1330, 1979. Macromolecules of limited tissue distribution can be conveniently regarded as antigens for localization and purification studies by the appropriate use of specific antisera. These "organ-specific " antigens are related t