Electron microscopic studies of intracisternal virus particles in Soehner-Dmochowski murine sarcoma virus-induced bone tumors of New Zealand Black rats

Soehner-Dmochowski murine sarcoma virus (Moloney)-induced bone tumors of New Zealand Black rats carry two morphologically different types of virus particles, namely, extracellular type C and intracisternal virus particles, which have thus far not been reported. These two types of virus particles have also been observed in the tissue culture cells derived from normal prostate tissues of A/Dm and BALB/c/Dm mice after inoculation of cell-free extracts of these bone tumors. The intracisternal virus particles, 90 to 120 nm in diameter, have always been found in the rough endoplasmic reticulum; they have two inner concentric layers with a relatively electron-lucent center, frequently showing cylindrical, chain-like, or multipolar budding forms. Type C virus particles produced by Soehner-Dmochowski murine sarcoma virus (Moloney)-infected prostate tissue culture cells from A/Dm and BALB/c/Dm mice belong to the murine sarcoma-murine leukemia virus group, as revealed by the fixed immunofluorescence test and by immunoelectron microscopy. The morphological and immunological relationship of intracisternal virus particles and other types of virus particles (such as type C, type H, and intracisternal type A virus particles) and intracisternal virus particles in guinea pig leukemia are defined by routine electron microscopy observations and by immunoelectron microscopy studies.

Effect of the Fv-1 locus in vivo: host range pseudotypes of murine sarcoma virus

Fv-1-specific host-range pseudotypes of murine sarcoma virus (MuSV) were developed by rescue from nonproducer cells with N- or B-tropic leukemia viruses. The MuSV(B) and MuSV(N) pseudotype viruses were tested in vitro and were restricted specifically by the Fv-1 gene locus. When the pseudo-type viruses were tested in vivo in mice of specific Fv-1 geno-types, tumor induction was completely restricted in nonpermissive animals, including athymic nude mice, whereas tumors grew progressively in permissive animals. All tumors regressed in adult heterozygous mice, but not in adult athymic nude mice.

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. Although the incidence and latency were approximately the same in hamsters of the three inbred strains, hamsters of the outbred stock exhibited almost complete resistance to tumor induction under identical experimental conditions. The morphologic types of neoplasms, i.e., lymphocytic leukemia, reticulum cell sarcoma, osteogenic sarcoma, and anaplastic sarcoma, induced in inbred hamsters were similar to those induced in outbred hamsters inoculated iv with 10(8.5) TCID50 SV40. The lymphocytic leukemias that developed in the 2 LSH/SsLak inbred hamsters were established as tumor transplants in vivo and as permanent cell lines in vitro.

Glial-mesenchymal tropism of in vivo avian sarcoma virus neuro-oncogenesis in rats

Intracerebral inoculation of avian sarcoma virus (ASV) in postnatal animals induces gliomas and sarcomas but no neuronal tumors. High titer Bratislava-77 strain ASV was inoculated intracerebrally in fetal F-344 rats between 17 and 20 days of gestation: a time of active neuronal proliferation. Following birth inoculated rats developed gliomas and sarcomas but no neuronal tumors. The results are evidence that the glial-mesenchymal tropism of in vivo ASV neuro-oncogenesis is independent of stage of neurocytodifferentiation at inoculation.

Type-C oncovirus isolate from human leukemic bone marrow: further in vitro and in vivo characterization

Rabbit corneal cells transformed by a putative human type-C helper virus pseudotype of the mouse sarcoma virus produce large amounts of transforming and non-transforming viruses. The virions are antigenically related to the woolly monkey (simian) sarcoma-leukemia type-C oncovirus. Typical sarcoma virus lesions developed in newborn rats injected with virus-producing rabbit cells. Cells producing only the putative type-C helper viruses as a result of exposure to a high dilution of transforming virus stock induce lymphosarcomas after inoculation into newborn rats.

Cellular attachment to implanted foreign bodies in relation to tumorigenesis

Previous experiments demonstrating a reduction of tumorigenicity by roughening the surfaces of plastics implanted in rodents, or by increasing the pore size of cellulose filter implants, were repeated with observations on cellular attachment to these objects and to filters strengthened and made impermeable by bonding to plastic. Round 13-mm discs of methylmethacrylate implanted S.C. in A/BiF/F50 + mice produced sarcomas in 12 percent of mice at 64 weeks. Tumor incidence increased to 60 percent (p less than 0.001) in mice receiving discs to which cellulose filters with pore sizes of 0.025 to 0.1 micrometer were bonded. No tumors occurred with discs covered by 0.45-micrometer filters, followed up to 83 weeks. Vinyl coverslips 15 mm square also produced no sarcomas when covered by 0.45 micrometer filters; plain vinyl produced sarcomas in 40 percent of mice at 64 weeks (p less than 0.001). Sanding of vinyl surfaces reduced tumorigenicity (p less than 0.05). Permeability, fragility, and storage capacity of filters are apparently not related to tumorigenicity. Surface roughness probably is related. Cells, mostly macrophages, were densely and uniformly attached to nontumorigenic surfaces from 24 hr to 2 years after inplantation but were distinctly fewer and not uniformly distrubuted on tumorigenic surfaces. Topology favoring attachment was inherent in 0.45-mum filters and was produced in plastic by gouging irregular excavations 10 to 15 micrometer deep.

High incidence of ependymomas induced by BK virus, a human papovavirus: brief communication

Ependymomas were produced in 44 of 50 Syrian golden hamsters and in 9 of 31 outbred Swiss mice inoculated intracerebrally with high-titer, purified BK virus (BKV). Tumors contained a T-antigen that reacted with BKV-specific T-antibody in immunofluorescence and complement-fixation tests. A proportion of tumor-bearing animals had antibodies to BKV T-antigen in their sera. BKV could be rescued from two tumor cell lines by Sendal virus-mediated fusion with Vero cells. A low, or lack of, oncogenic activity was displayed by BKV inoculated sc, ip, or iv.

Induction of simian virus 40 (SV40) transplantation immunity in mice by SV40-transformed cells of various species

Specific tumor rejection was obtained with the use of simian virus 40 (SV40)-transformed cells from several species including man, rat, ape, sheep, and hamster. Growth of the syngeneic sarcoma mKSA in BALB/c mice was strikingly inhibited following a single immunization with as few as 10(3) intact, viable cells. Non-SV40-transformed cells did not induce tumor rejection activity nor did SV40-transformed lines induce immunity against the 3-methylcholanthrene-induced sarcoma Meth A, syngeneic with BALB/c mice. A close relationship existed between the tumor rejection antigen, the tumor-specific transplantation antigen (TSTA) located on the plasma membrane, and the intranuclear tumor antigen (T-ag). Both were associated with the DNA sequence of the early region of the SV40 genome, and TSTA activity was found in the nucleus. However, we did not observe a close parallelism between T-ag activity and TSTA. Neverthesless, the results strongly suggested that TSTA, like T-ag, was encoded by the virus.

Transformation of rat liver epithelial cells by Kirsten murine sarcoma virus

We studied the transformation of epithelial, diploid cell lines (RL-33 and RL-34) derived from W rat liver by the Kirsten murine sarcoma virus. On days 4-5 after virus infection, the epithelial cells began to pile up focally, forming small projections and releasing round cells from the foci. The epithelial cells grew in chains or as islets and grew in suspension above the cells attached to the bottom of the flasks when the cultures reached the confluent stage. The virus titration pattern was "one-hit." Three classes of transformed cells were isolated with respect to virus release and antigen expression: 1) virus producer, 2) non-producer, and 3) sarcoma-positive, leukemia-negative cells. When transplanted sc into newborn rats, the transformed cells produced sarcomas. The transformed cells formed within 1-3 days larger aggregates than those of their normal counterpart cells when suspended in liquid growth medium above an agar base. Aggregate properties (size, viability, and proliferation) of transformed cells correlated with growth in soft agar and tumorigenicity. RNA-dependent DNA polymerase and type C virus particles were readily induced in the normal rat liver epithelial cells after exposure to 5-iodo-2'-deoxyuridine.

Biologic and biochemical properties of detergent-solubilized tumor-specific transplantation antigen from a simian virus 40-induced neoplasm: brief communication

The detergent Nonidet P40 was used to solubilize tumor-specific transplantation antigens (TSTA) from crude membranes obtained from dissociated cells of simian virus 40-induced sarcoma of BALB/c mice. A good recovery of specific tumor rejection activity was observed. One fraction, fraction V, was obtained following polyacrylamide-agarose filtration of the solubilized material, and this fraction contained most of the activity. An increased specific activity followed gel filtration. Preliminary data from lectin column chromatography of the active fraction V indicated a separation of TSTA activity from H-2 activity.

Delayed foreign-body tumorigenesis in mice infected with lactate dehydrogenase-elevating virus: Brief communication

Female and male CBA/H mice were infected with lactate dehydrogenase virus (LDV). Two weeks later, these mice and noninfected controls received double sc implants of unplasticized vinyl chloride-vinyl acetate copolymer films (0.2 X 15 X 22 mm). Foreign-body (FB) tumorigenesis was delayed in LDV-infected females and males by 2 months. This result could not be explained by an effect of LDV on cellular immunity, inasmuch as cellular immunity does not influence the course of FB tumorigenesis.

Oncogenic and nononcogenic bovine adenoviruses and guanine-cytosine content of their DNA

Bovine adenoviruses types 1, 2, and 3 were purified and concentrated by polyethylene glycol precipitation and CsCl density-gradient centrifugation. The efficiency of recovery of infective particles was 64 to 80%. The guanine-cytosine contents of DNA of the nononcogenic types 1 and 2 and the highly oncogenic type 3 were found to be 62, 61, and 48%, respectively--a pattern similar to that of nononcogenic and oncogenic human adenoviruses.

Isolation of T-lymphocytes from disaggregated tumors, with high purity and good percentage recovery

A combination of two cell separation methods was utilized for the isolation of thymus-derived lymphocytes (TL) from enzymatically disaggregated tumors. Passage through Sephadex G-10-glass bead columns to remove adherent cell types followed by exposure to IgG-coated sheep red blood cell monolayers for removal of Fc receptor-bearing inflammatory cells provided functional TL suspensions of high purity with good percentage recovery.

The effect of immunotherapy with BCG on the development of radiostrontium (90Sr)-induced osteosarcoma

The development of radiostrontium-induced osteosarcoma was studied in BCG-treated and in untreated control mice. Within the observation period of 420 days after the administration of radiostrontium there was a total tumour-incidence of 89.5 and 90.5 per cent for the respective groups of animals. There was no statistically significant difference between the two groups, neither with regard to the time of the first roentgenographic appearance of the osteosarcoma, nor concerning the total tumour incidence , nor with regard to the distribution of the primary sites of the tumours. The tumours of the BCG-treated animals showed a clear tendency to a slower growth rate in comparison to that of the tumours in the control animals. This effect was probably immunological in nature. The mortality in osteosarcoma following radiostrontium administration, however, showed no significant difference between the two groups. Light microscopical and ultrastructural examination did not disclose any clear structural difference between the tumours from BCG-treated and untreated control animals.

The relationship between age-dependent immunological competence of host and tumor growth in the hamster-bovine adenovirus type 3 system

The relationship of aging to carcinogenesis was immunologically examined in the hamster-bovine adenovirus type 3 system. The age of animals at the time of virus inoculation influenced the tumor growth and latency period, but not the tumor incidence. The immunological competence of hamsters to sheep red blood cells became matured around 4 weeks after birth and was not affected by the infection of bovine adenovirus type 3 (BAV-3). The strength of transplant immunity was dependent on the age of animals at the time of immunization. The growth of progressive type of tumors induced by inoculation with BAV-3 into younger animals was inhibited by the repeated inoculation of excess dose of BAV-3, administration of BCG and transfer of sensitized lymphocytes during the tumor latency. The growth of non-progressive type of tumors induced by inoculation with BAV-3 into adult hamsters was accelerated by administration of antithymocyte serum or thymectomy. The tolerance to tumor specific transplantation antigens did not play a critical role in the present system. The blocking activity to sensitized lymphocytes was demonstrated in the sera taken from hamsters developing a progressive type of tumor even in the early period of carcinogenesis.

Migration inhibition by an agarose microdroplet assay: monitoring of tumor-associated antigens on a simian virus 40-induced sarcoma

Macrophage migration inhibition assays, with a direct agarose microdroplet method, were used to monitor TAA activity of preparations of SV-40-induced mKSA cells. These preparations included cell-free crude membranes, papain-solubilized and NP40 detergent-solubilized membrane extracts from mKSA tumor cells. The assay was extremely sensitive and could detect migration inhibition reactivity with all three types of antigenic preparations with concentrations as low at 250 ng protein/ml. The reactivities were quite reproducible from experiment to experiment using the same or different lots of these antigen preparations, and the reactivities were specific in that peritoneal exudate cells from BALB/c mice, immunized with antigenically unrelated but syngeneic plasmacytomas, were not inhibited by these antigens. The results demonstrated the usefulness of this assay in rapidly detecting small concentrations of partially purified TAA preparations by using small number of immune cells.

Abrogation of resistance to feline oncornavirus disease by immunization with killed feline leukemia virus

Four-week-old specific-pathogen-free cats were immunized with a combined vaccine composed of killed feline leukemia virus and killed feline oncornavirus-associated cell membrane antigen-containing tumor cells. Immunization induced feline oncornavirus-associated cell membrane antigen antibody titers ranging from 1:32 to 1:256 but did not elicit detectable virus-neutralizing antibody titers. Kittens immunized with tumor cells alone developed higher feline oncornavirus-associated cell membrane antigen antibody titers (ranging from 1:512 to 1:2048) than those given the combined vaccine. All kittens were challenged with virulent Dynder-Theilen feline sarcoma virus at 12 weeks of age. Seventy-five % of the kittens vaccinated with combined vaccine and 67% of unvaccinated control kittens developed progressive fibrosarcomas after challenge. By contrast, none of the kittens vaccinated with killed tumor cells alone developed progressive fibrosarcomas after challenge. The combined vaccine did not, however, inhibit the induction of feline leukemia virus viremia.

Development of cellular anti-tumor immunity in chickens bearing tumors induced by Rous sarcoma virus

The technique of peripheral lymphocyte stimulation in response to antigen was used to demonstrate the existence of cell-mediated anti-tumor immunity in chickens bearing tumors induced by avian sarcoma viruses. The expression of this anti-tumor response against virus-containing transformed cell culture supernatant fluids and cell extracts varied among animals in terms of time after inoculation with the oncogenic agent. Animals whose tumors had completely regressed rapidly lost the ability to mount such continuing immunity. In addition, we found evidence that some normal animals express endogenous levels of natural immunity against neoplasms induced by these viruses and/or against the viruses themselves.

Characterization of immune responses to spontaneous hamster lymphomas

Tumor resistance could be induced against the transplantation of cell lines derived from spontaneous lymphomas that occurred in the third of three lymphoma epizootics in a hamster colony. Immunization of normal hamsters with irradiated lymphoma cells promoted resistance to homologous lymphoma challenge and prevented the development of spontaneous lymphomas when immunized hamsters were exposed to the contaminated colony. This immunity could be transferred in an adoptive transfer assay. Resistance to direct challenge was not extended to simian virus 40(SV40)-induced sarcomas carrying SV40 tumor-specific transplantation antigen nor to herpesvirus-induced carcinoma cells, indicating specificity. The nature of the antigen(s) involved was discussed.

Inflammatory cells in solid murine neoplasms. III. Cytotoxicity mediated in vitro by macrophages recovered from disaggregated regressing Moloney sarcomas

Macrophages (Mphi) were recovered from disaggregated, spontaneously regressing Moloney sarcomas for in vitro testing of their cytotoxic capabilities. At a 3:1 ratio, Mphi in monolayers efficiently killed (51Cr release) a variety of tumor target cells without regard to antigenic specificity. Within 24 hr most of their cytolytic potential was lost. Killing could be restored, however, if Mphi were replated at higher cell densities. A soluble, heat-stable, dialyzable inhibitor of thymidine incorporation, which did not interfere with cellular proliferation, also was produced by Mphi recovered from Moloney sarcomas. The finding of such a competitive inhibitor, probably cold thymidine, in supernatants further opened to question the validity of radioisotope incorporation into DNA as a measure of Mphi-mediated cytostasis. The data presented suggest that Mphi may participate in the regression process by directly killing tumor cells, thus complementing the antigen-specific cytolytic capabilities of the T lymphocytes that are also found in large numbers within regressing Moloney sarcomas.

Foreign-body tumors of mice: strain and sex differences in latency and incidence

Sarcomas were induced by sc implantation of unplasticized polyvinylchloride acetate films in female and male mice of strains AKR/J, BALB/cJ, BALB/cWat, CBA/H and CBA/H-T6, C3H/HeJ, C57BL/10ScSn, C57BL/6J-bgj, C57BL/cdJ, DBA/-1J l/LnJ, LP/J, SJL/J, X/Gf, 129/J, and hybrids (CBA/H-T6 X AKR/J)F1, (C57BL/10ScSn x CBA/H or CBA/H-T6)F1, (C57BL/6J-bgj x C57BL/6J)F1. The strains and sexes showed marked differences in incidence and mean latency of resulting tumors. Crucial information was provided for the selection of appropriate mouse strains for the study of interrelationships between genotypes, defined somatic properties, and the multifactorial process of foreign-body tumorigenesis.