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Electron microscopic, immunologic, and biochemical methods have been used in an attempt to detect and characterize oncornaviruses in human prostatic carcinoma (PCa) and benign prostatic hyperplasia (BPH), and in prostates of mice of high and low mammary cancer or leukemia strains. Ultrastructural examination of 37 PCa and nine BPH specimens has revealed the presence of particles resembling type C virus in five cases of PCa and one of BPH, and also two different types of intracisternal virus-like particles in seven other cases of PCa. Type B virus particles have been observed in prostate of old mice of high mammary cancer strains, while type C virus particles have been found in the prostates of most mice of all the ten strains examined. Immunofluorescence tests with sera from patients with PCa and BPH and with cells derived in vitro from PCa have shown that sera of patients with PCa contained antibodies directed mainly against Forssman-like and tumor-related antigens. In immunofluorescence tests of antisera to major proteins of oncornaviruses with cells of PCa and BPH tissues grown in vitro, positive reactions have been obtained with antisera to p30 protein of murine, feline, and simian type C viruses. Fixed immunofluorescence (FIF) tests of sera of PCa (38%) and BPH (25%) and of some normal donors (27%) gave positive cytoplasmic reaction with mouse prostate cells infected with Soehner-Dmochowski murine sarcoma virus (SD-MSV). Immunoferritin tests of 11 sera positive by FIF gave ferritin labeling of type C virus particles in the SD-MSV-infected mouse prostate cells...

The possible involvement of RNA tumor virus genomes in human cell transformation was investigated. Forty-nine cell cultures from neoplastic, normal, or embryo tissues were examined for transformation, following inoculation of murine leukemia virus (MuLV), feline leukemia virus (FeLV) grown in human cells, or bone marrow aspirates from leukemia patients. Five cultures exhibited transformation (1 after inoculation of MuLV grown in human cells; 4 after inoculation of human leukemic bone marrow), and 4 were established as cell lines. They were derived from giant cell tumor and fibrosarcomas. The established transformed cells formed colonies in soft agar, grew progressively in immunosuppressed mice, and carried antigens common to FeLV and MuLV. Although virus particles were not seen in these cultures, 68S RNA was detected in their media. Medium from nontransformed parent cultures also contained 68S RNA but in amounts about 15 times less than in transformed cultures. Transformed human cells passaged in mice produced both type C virus particles and 68S RNA. Antigens common to MuLV and FeLV were found in these particles. However, the results of biological and serological studies indicate their difference from conventional MuLV and FeLV. The relationship of this virus and 68S RNA found in transformed cultures remains to be determined.

Short- and long-term co-cultures of 49 cases of human osteosarcoma cells with bone marrow or peripheral blood cells of patients with different types of leukemia were studied. Morphological changes were observed in 7 of 13 long-term co-cultures resembling those induced by RNA tumor viruses. The changes were accompanied by appearance of cytoplasmic antigen as shown by fixed immunofluorescence test with sera from patients with osteosarcoma, leukemia, and of some apparently normal blood donors. Absorption with Forssman-like substances, whole human embryo cells or osteosarcoma cells demonstrated the reaction to be due to tumor antigen(s) in co-culture cells showing morphological changes. Electron microscopy showed a few type C virus particles in one co-culture. Cell-free filtrates of fluid from the transformed co-cultures induced morphological changes in 1 of 4 human embryo cultures. Uninoculated embryo cultures or those inoculated with filtrates from parental sarcoma or leukemia cultures showed no morphological changes. Human embryo cell cultures treated with fluid from parental leukemic bone marrow but not from parental sarcoma cultures showed appearance of cytoplasmic antigen by immunofluorescence test with sera of osteosarcoma and leukemia patients and of some apparently normal blood donors. Transformed human co-cultures showed the cytoplasmic antigen with 28 of 48 sera of osteosarcoma and leukemia patients tested, after absorption with Forssman-like material, human embryo, and mycoplasma suspensions. Fourteen of 49 sera of normal donors were also positive with the transformed co-cultures. Similar results were obtained in an earlier series of experiments with human embryonic cultures transformed by fluid from different osteosarcoma-leukemia co-cultures when examined by fixed immunofluorescence tests with sera of patients with osteosarcoma and leukemia. In 2 whole human embryo cell cultures showing morphological changes high molecular weight RNA was found, similar to that of RNA animal tumor viruses and in one of the cultures transient reverse transcriptase was detected.

Morphologic, tissue culture, immunologic, and biochemical methods have been used in an attempt to detect and characterize oncogenic viruses or their subviral components in cells derived from human prostatic carcinoma (PrCa) or benign prostatic hyperplasia (BPH). Electron microscopy was used to characterize the ultrastructural features of normal and neoplastic prostatic tissue. Examination of specimens of prostatic tissue from 34 patients with PrCa, ten patients with BPH, and three patients with bladder tumor (BT) revealed the presence of particles resembling type-C virus in three cases of PrCa and structures resembling budding type-C virus particles in one case of BPH. Fifty human prostatic tissue specimens have been set in tissue culture, of which 30 have been successfully grown for varying periods of time. Of 20 currently active cultures, nine consist primarily of epithelial cells. Immunofluorescence and mixed hemadsorption tests of cells derived from benign and malignant prostatic tissue and sera derived from patients with PrCa, BPH, BT, and other types of tumors, and from normal donors revealed that sera from patients with PrCa, BPH, or BT contain antibodies to antigens in cells derived from PrCa, BPH, or BT. The nature of these antigen-antibody reactions is under study. Initial biochemical studies have not detected reverse transcriptase in the tissue culture fluid from a small number of sparsely growing PrCa cultures nor specific gene sequences homologous to murine leukemia virus-Rauscher genomic RNA in preparations of either normal or malignant prostatic cell DNA. The results of these preliminary studies have demonstrated the applicability of the techniques employed to the study of the relationship of viruses to human PrCa and have provided a number of promising leads for further investigation.

The results of molecular hybridization experiments have demonstrated that the RNA genome of RD-114 virus has extensive nucleotide sequence homology with the RNA genome of Crandell virus, an endogenous type C virus of cats, but only limited homology with the RNA genomes of feline sarcoma virus and feline leukemia virus. The genomic RNAs of RD-114 virus and Crandell virus also had identical sedimentation coefficients of 50S. A structural rearrangement of genomic RNA did not exist within released RD-114 virions, whereas a structural rearrangement of genomic RNA did occur within feline sarcoma virions and feline leukemia virions after release from virus-producing cells.