Microenvironmental influences on the in vivo behavior of neoplastic lymphocytes.

A transplantable hamster lymphocytic neoplasma of probable monoclonal derivation, induced by the oncogenic DNA simian virus 40, has been adapted to grow in the allogeneic host either as leukemia (characterized by dissemination and poor prognosis) or as lymphoma (characterized by localization and favorable prognosis) [Diamandopoulos, G. Th. (1978) Proc.

Differences in behavior and prognosis between leukemic and lymphomatous forms of a transplantable hamster lymphocytic neoplasm induced by simian virus 40.

A lymphocytic leukemia of probable monoclonal derivation, induced in a Syrian golden hamster by the oncogenic DNA simian virus 40, was adapted to grow in the allogeneic host either as leukemia or as lymphoma. The leukemia, which was produced by transplanting subcutaneously neoplastic lymphocytes that had circulated through and/or proliferated in lymph nodes and spleen, was characterized by dissemination with systemic manifestations and poor prognosis. The lymphoma, which was produced by transplanting subcutaneously neoplastic lymphocytes that had proliferated at subcutaneous sites of cell implantation, was characterized by localization and favorable prognosis.

Incidence, latency, and morphologic types of neoplasms induced by simian virus 40 inoculated intravenously into hamsters of three inbred strains and one outbred stock.

The incidence, latency, and morphologic types of neoplasms induced in hamsters of the three inbred strains LSH/SsLak, LHC/Lak, and MHA/SsLak, inocuated iv at 3 weeks of age with 10(7.5) median tissue culture infective dose (TCID50) of simian virus 40 (SV40). were determined and compared with those of the outbred stock LVG/Lak.

Loss or persistence of the differentiated state of simian virus 40-induced hamster tumor cells before and after serial passage in culture.

The transformed cells that arise from among the hamster epithelial and mesenchymal cells exposed to SV40 in vitro are, as a rule, fibroblastoid and pleomorphic rather than epithelioid. Moreover, the neoplasms that these transformed cells induce in the allogeneic host are spindle cell sarcomas and pleomorphic sarcomas rather than carcinomas. Since this phenomenon may result from cellular dedifferentiation in culture, to the extent that the anaplastic morphology and lack of specialized function can no longer suggest the cell or origin, we investigated the fate of the differentiated state of cells of three types of SV40-induced hamster tumors before and after serial passage in vitro.

Effect of host age, virus dose, and route of inoculation on tumor incidence, latency, and morphology in Syrian hamsters inoculated intravenously with oncogenic DNA simian virus 40.

Three-week-old to 12-month-old male Syrian hamsters were inoculated iv with 10(8.5) median tissue culture infective dose of simian virus 40 (SV40). Three-week-old hamsters were similarly inoculated with aliquots of SV40 of progressively decreasing titers.

Adenovirus-like transformation of hamster embryo cells mediated by Simian virus 40.

Primary hamster cells, derived from embryos of 10 days gestation, were exposed in culture to the oncogenic effect of the DNA virus SV40. While the fibroblastoid cells transformed soon after virus inoculation, the small, round or oval cells also present preserved their characteristic mophologic features for a long time. When these cells finally transformed under the influence of SV40, they developed the capacity to induce, in the homologous host, small-, round-cell sarcomas, that were morphologically indistinguishable from neoplasms usually produced by adenoviruses.

Leukemia, lymphoma, and osteosarcoma induced in the Syrian golden hamster by simian virus 40.

Leukemia, lymphoma, and osteogenic and anaplastic sarcomas develop in Syrian golden hamsters inoculated intravenously at 3 weeks of age with simian virus 40, which is a popova virus. Previously, only RNA and herpes DNA viruses have been recognized as capable of inducing leukemia and lymphoma in mammals. The significance of these findings is emphasized in relation to the nature of viral agents that may be involved in analogous diseases of man.

Virus-specific deoxyribonucleic acid in simian virus 40-exposed hamster cells: correlation with S and T antigens.

Several homologous hamster embryonic cell lines, transformed in association with simian virus (SV) 40 infection, were examined for the presence of deoxyribonucleic acid (DNA) complementary to SV40 ribonucleic acid (RNA) made in vitro. The methods employed permitted the detection of 10(-5) mug of viral DNA in 100 mug of cellular DNA, corresponding to one-fifth of an SV40 DNA molecule per cell. Those lines which contained both the SV40 surface (S) and tumor (T) antigens also contained DNA complementary to SV40 RNA synthesized in vitro.

Virus-specific nucleic acids in SV40-exposed hamster embryo cell lines: correlation with S and T antigens.

A number of homologous SV40-exposed hamster embryonic cell lines were examined for the presence of RNA complementary to SV40 DNA. Only those lines containing the SV40 T antigen were found to have such virus-specific RNA. In lines containing the SV40 S antigen, but not the SV40 T antigen, virus-specific RNA was not detected.