Antigenic activity of human urothelial tissue

Partially purified extracts from 71 human urothelial tumors and from 75 human urothelial non-tumor tissues were used as competing antigens in competition radioimmunoassay in an effort to detect the presence of 1 of the structural components of type C-ribonucleic and viruses, the p30 core protein. Testing of the tissue extracts was carried out by homologous and heterologous assay systems using 125I-labeled murine (Friend) and feline (Rickard) p30 antigens and anti-feline and anti-murine p30 antisera. The homologous assays were designed to detect the presence of p30 antigens in the human tissue extracts having similar characteristics to the p30 antigens of either the feline or murine type C viruses. The heterologous assay system was designed to detect interspecies antigenic determinants common to murine and feline viruses and also primate viruses. A competing antigen present in 28 per cent of the tissue extracts assayed demonstrated an antigenic protein that competed with the viral p30 protein used in the heterologous radioimmunoassay system and to a lesser extent in the homologous feline radioimmunoassay system. Antigenic competitor proteins were found in tumor and non-tumor tissue. These data suggest that some human urothelial tissues contain at least part of the genome of 1 or more type C viruses. Those tissues that are positive only in the heterologous assay system behave like viral p30 antigens already identified in tissues of several other primates. Those tissues that are positive in the heterologous assay system and the homologous system indicate that the p30 antigenic activity is closely related to that p30 present in feline C-type viruses. Further purification and more detailed characterization of those competing proteins are now under study.