Expression of differentiation and murine leukemia virus antigens on cells of primary tumors and cell lines derived from chemically induced lymphomas of RF/J mice.

Abstract

ABSTRACT3-Methylcholanthrene (MCA) skin painting rapidly induced a 100% incidence of thymic lymphomas in RF/J mice. Tumors developed exclusively in cells of the Tlymphocyte lineage and displayed the surface phenotype: Thy-1+, Lyt-1+9 Lyt-2+9 Qa-1+9 H-2K+q H-2D', TL-, Ig-, Ia-. This phenotype resembled that of cortisone-resistant, medullary thymocytes, whereas the phenotype of spontaneous AKR thymomas resembles that of cortisone-sensitive, cortical thymocytes. The phenotype differed very little from one tumor to another and was maintained during syngeneic passage in vivo and adaptation to growth in culture. Infectious ecotropic murine leukemia virus (MuLV) was produced in a minority of primary tumors and cell lines, but no xenotropic or mink cell focus-inducing virus (MCF) MuLV production was reliably detected. MuLV-related antigen expression on normal thymocytes increased in an age-dependent manner, and levels on thymoma cells were similar to those on thymocytes from agematched normal controls. MuLV nonproducer tumor cells expressed few or no epitopes of AKR ecotropic gp7O, but they were positive when tested with an antiserum prepared against MCFnv glycoprotein.

Lack of ecotropic virus involvement in induction of lymphomas in DBA/2J mice by 7,12-dimethylbenz(a)anthracene

“…Most chemically induced lymphomas that have been characterized previously in mice are thymic lymphomas, presumably of the T-cell lineage (16,17,20,46). This T-cell origin has been confirmed for MCA-induced RF/J thymic lymphomas by using cell surface markers that are specific for different lymphocyte cell lineages (17). DMBA-induced DBA/2J lymphomas have not been characterized previously according to lineage.…”

“…However, the role of endogenous retroviruses in chemically induced lymphomas is not totally clear. For example, retroviruses do not appear to be involved in the induction of chemically induced T-cell lymphomas in RF/J mice (5,17), and neither somatically acquired proviruses nor virally induced rearrangements in cellular protooncogene loci, such as Myc and Pim-1, have been observed in RF/J lymphoma DNAs. In contrast, virally induced Myc and Pim-1 rearrangements have been detected in chemically induced T-cell lymphomas of AKR mice (46).…”

Studies on the mechanism of 1,3-butadiene-induced leukemogenesis: the potential role of endogenous murine leukemia virus.

“…Leukemogenic retroviruses have been isolated from radiation-induced leukemias in certain strains including the parent strains of the B6C3F1 hybrid mouse (14)(15)(16)(17)(18)(19)(20), and there is evidence that ecotropic and recombinant MuLV play critical roles in strain-specific spontaneous leukemogenesis (12). In spontaneous leukemias of the mouse, the role for MuLV is definitive (8) (22,23).…”

Absence of mouse mammary tumor virus proviral amplification in chemically induced lymphomas of RF/J mice

“…The approach that we used was to examine primary tumors, animal-passaged tumors, and tissue culture cell lines derived from MCA-induced lymphomas for the presence of MMTV proviruses integrated at novel sites in the cellular genome. DNA isolated from MCA-induced primary thymic lymphomas (3,4,14) was digested with EcoRI (New England BioLabs, Inc.), which cleaves most MMTV genomes once. Samples (20 p.g) of digested genomic DNA were resolved electrophoretically in 0.8% agarose gels and transferred to nitrocellulose as described previously (16).…”