RNA Type C Virus Antigens in Hamster Cells Transformed by Carcinogenic DNA Viruses and Chemicals (original) (raw)
Related papers
Induction of Type C Viruses in Cultured Guinea Pig Cells
Journal of Virology, 1973
Particles morphologically resembling type C viruses were activated by bromodeoxyuridine (BUdR; 10 −4 M) treatment of cultured guinea pig cells. Virus particles were isolated from the cells of normal and leukemic strain 2 and random-bred guinea pigs (adult and embryonic). Immature virus particles with electron-lucent cores were found in the cytoplasmic matrix. The mature particles with electron-dense cores were found outside the cells and some appeared in the process of budding from the plasma membrane. The peak of virus production was observed within 4 days of BUdR treatment. When compared to the amount of virus produced in darkness, visible light enhanced virus production, whereas exposure of BUdR-treated cells to UV light either had no effect or inhibited virus production. Virus particles had a density of 1.16 gm/ml, possessed an oncornavirus-specific reverse transcriptase, and contained a large-molecular-weight RNA (65-70 S ) which dissociated into 36 S subunits after heat denatu...
Neoplasma
Some properties of the viruses induced by chemical carcinogens and mutagens from hamster cell line transformed with Schmidt-Ruppin strain of avian sarcoma virus were investigated. Avian sarcoma viruses induced with 3-m.ethylcholanthrene, 4-nitroquinoline-l-oxide and 5-azacytidine were oncogenic for young hamsters. The most potent virus in the ability to induce tumours in hamsters was the virus induced by 5-azacytidine. This virus was different from control virus in its high level of RNA-dependent DXA-polymerase activity and has also high relative plating efficiency for duck cells. It was concluded that induction of infectious virus from virogenic hamster cell line by chemical carcinogens is leading to mutation of virus especially in the case of virus induction with mutagen 5-azacytidine.
Cell Generation and Type C Virus Expression in the Human Embryonic Cell Strain HEL-12
Journal of General Virology, 1977
The spontaneous expression of a type C virus in a diploid strain of human embryonic lung fibroblast-like cells (HEL-I2) was examined during serial culture. Virus antigen expression was determined by indirect immunoftuorescence with antisera to disrupted simian sarcoma virus and the 28 o0o mol. wt. internal antigen of the endogenous cat virus RD-I 14. Virus production was examined by reverse transcriptase assays of culture fluids. Virus antigens were not detected for 25 days after frozen, primary HEL-t2 cells were reinstated in culture. The cells expressed virus antigens but did not release virus particles between 25 and 8o days. Spontaneous virus release and maximal antigen expression occurred in cells grown for 8o to r 20 days. Virus particles were not detected after 12o days although virus antigens persisted until the experiment was terminated. The HEL-12 virus was infectious for cell cultures of human, rhesus monkey, dog and rabbit cells. The proportion of SiSV-like and RD-II4-1ike antigenic components of HEL-I2 virus were altered by passage through heterologous cells suggesting heterogeneity of the HEL-12 virus population. monkey (Lagothrix spp.) with fibrosarcoma.
In vitro isolation of stable rat sarcoma viruses
Proceedings of the National Academy of Sciences of the United States of America, 1978
A Sprague-Dawley (SD-1) rat embryo culture, at low passage level, released an endogenous ecotropic type C virus (SD-RaLV) and after about 20 further passages it underwent spontaneous transformation. The SD-RaLV, released from the transformed cells, did not cause rapid transformation of other rat embryo cells. However, when the transformed cells were repeatedly cocultivated with three different chemically transformed and serially transplanted rat tumor cell lines (sarcoma, carcinoma, and hepatoma), rapidly fibroblast-transforming "sarcoma" viruses (RaSV) were recovered after each attempt. RaSV was not recovered from one of these tumor cell lines before transplantation, nor could focus-forming virus be rescued from these same tumor cells by cocultivation with other cells releasing heterologous type C viruses. Foci were induced on normal rat kidney and several other rat embryo cell strains within 7-15 days and both productive and nonproductive NRK clones were derived. The pro...
International Journal of Cancer, 1974
The iiijertious properties of viruses produced by Ehrlich tumor cells (E) , the A9 ,srth/irie of' mouse L cc#s (L) , their hj-brids (E L , arid E L) und high-maligtiarit suhlincs yf' the low-maligtiant hybrid line (EL,,, i W P r C investigated. The infectivity a.s.say.s wen' utitigetr induction ow JLS-V9 cells, antigenic cotiversion und focus iriductioii otr S I L wlls (D.56 .subhe) unc/.focus .formatioti oti BAL Bl3 T3 cells. The E and L viruses, pro-rlrrrc~d by the pavetitul cells, were detected irr the JLS-V9 test but were distitiguished in S 1 L ~~~ urid BALBI3T3 cells. The L virus wus ,focus-positive, the E virus .focustiegutive (B A L B/3T3). For utitiAwiic cotiversion, the L virus was negutive and the E virus positive (D S 6). The hybrid cell line, tested 011 sevi~rctl occasions after the hydridizatioti evetit, produced viruses with characteristics similur to both E arid L viruses, riyurcllc'ss of the complete or rerlucd chromosome numbers. The muligriunt sublines selected from the hybrid showed pryferetrtial loss of' the A9 puretit-derived biarmed chromosomes. Otie of thi.se lities produced virus (EL,,,) with infective properties similur to those of' the E virus. This suggests thut the virus produced by u particular cell line is determitred by the cell getlome. Another maligtiutit subline was .fourid to hi, ncycrtive .for productiotr of ii1fi.ctiou.s virus in all three indicator systems. The infectious properties of viruses produced in hybrid cells, resulting from the fusion of Moloney lymphomas and L cells (A9 subline) were reported previously (Fenyo et ul., 1971, 1973). The viruses produced by the parental (Y. Yr and L) and hybrid cells (YL and YrL) were characterized by a panel on infectivity assays. These assays did not give concordant results when different viruses were used, allowing the infectivity pattern to be used as viral marker.
Journal of Virology, 1979
Low-infectious, nontransforming type C virus was isolated from an in vitro spontaneously transformed ST/a mouse cell line, ST-L1. The virus released by ST-L1 cells was NB-tropic and XC − . It gave rise to very small peroxidase antibody plaques (PAP) in cultures which initially were nonproducing. Sodium dodecyl sulfate (SDS)-polyacrylamide gels of the structural proteins of the ST-L1 virus showed an envelope glycoprotein with an apparent mass of 65 kilodaltons (kdal). The mouse cells SC-1, BALB/3T3, and NIH/3T3 could be productively infected with cell-free supernatants from the ST-L1 cell line; however, virus was detected in supernatant fluids only after two to four subcultures of the infected cells. The virus thus produced was XC + and a large plaque former. The virus released from infected SC-1 cells was N-tropic, whereas the viruses from infected NIH/3T3 and BALB/3T3 cells were NB-tropic. The structural proteins of the N- and NB-tropic viruses could be distinguished on SDS polyacr...
Characteristics of hamster cells transformed by the combined action of chemical and virus
International Journal of Cancer, 1978
Pretreatment of hamster cells with chemical carcinogen enhances transformation by a simian adenovirus, SA7. Such transformants were compared t o cells transformed by SA7 alone for the presence of virus-specified antigens, and for the ability t o clone in soft agar and to form progressively growing sarcomas in hamsters. The SA7 '' T " antigen content and the relative cloning efficiencies in agar of cell lines of both groups were similar.
International Journal of Cancer, 1979
The putative human helper virus SU&21/A204V, isolated by Nooter et al. in 1977 from human leukemic bone-marrow cells following co-culture with normal fetal canine thymus cells, CfZth, has been characterized with respect t o i t s major viral core protein, reverse transcriptase, and nucleic acid sequences. The results of these analyses show that this virus is not distinguishable from the woolly monkey t y p e 4 virus, SSAV-1, by the techniques employed. CARACTERISATION D'UN VIRUS DE TYPE C PRODULT PAR COCULTURE D E CELLULES DE MOELLE OSSEUSE LEUCEMIQUE HUMAINE ET DE THYMUS F E T A L CANIN Le virus SKA-21iA204V. que I'on croit t t r e u n virus auxiliaire humain et qui a ete isole par Nooter c z ( ol. en I977 B partir de cellules de moelle osseuse leucemique humaine apres coculture avec des cellules normales de thymus f e t a l canin, CfZth, a ete caracterise du point de vue de la proteine virale majeure interne ("care protein"), d e la reverse transcriptase et des sequences des acides nucleiques. Les resultats de ces analyses montrent que cc virus ne peut etre distingue d u virus d e type C du singe iaineux, le SSAV-I, tout au nioins avec les techniques utilisees.
Acceleration of transformation of rat embryo cells by rat type C virus
Journal of Virology
Sprague-Dawley and Fischer rat embryo cells became spontaneously transformed about 20 passages after release of endogenous ecotropic type C virus (SD-RaLV and F-RaLV). The virus-producing transformed cells showed loss of contact inhibition, increased growth rate, and tumorigenicity in vivo. Exogenous infection of other Fischer rat embryo cultures in early passage with SD-RaLV and F-RaLV markedly accelerated their rates of transformation.