| mouse leukemia and solid tumors treated with bone marrow grafting. | | 1976 | 11588 |
| the role of prolactin in carcinogenesis. | | 1976 | 14442 |
| mammary tumor virus dna: a glucocorticoid-responsive transposable element. | | 1978 | 28200 |
| identification, partial purification and biochemical characterization of gamma-glutamyltranspeptidase present as a membrane component in skimmed milk and milk fat-globule membranes, and in mammary-tumour virus from the milk of infected mice. | the enzyme gamma-glutamyltranspeptidase was reproducibly found to be associated with mouse milk particles; it is present in milk fat-globule membranes and mouse mammary-tumour virus of infected swiss mice, also in particles from the milk of uninfected mice. the enzymatic activities observed range among the highest reported for mammalian tissues. the enzyme was partially purified from mouse mammary-tumour virus, and from milk fat-globule membranes. the molecule requires the presence of detergents ... | 1979 | 36916 |
| unlinked control of multiple glucocorticoid-induced processes in htc cells. | htc cell variants chosen for their lack of tyrosine aminotransferase (ec 2.6.1.5) (tat) induction by glucocorticoids were tested for interrelated effects on other glucocorticoid responses: tat induction by dibutyryl cyclic amp (dbcamp) +/- dexamethasone, glutamine synthetase (gs) induction, cyclic nucleotide phosphodieterase (pde) suppression, inhibition of alpha-aminoisobutyric acid (aib) uptake, inhibition of plasminogen activator (pa), and induction of mouse mammary tumor virus (mtv). loss of ... | 1979 | 39858 |
| posttranscriptional regulation of glucocorticoid-regulated functions. | relying heavily on studies of tat regulation in cultured rat hepatoma cell lines, we have attempted in this brief review to discuss possible mechanisms for posttranscriptional regulation of glucocorticoid-sensitive enzymes and to chronicle the evidence for and against posttranscriptional mechanisms for specific enzyme induction by glucocorticoids. initially, mechanisms were considered that would reconcile results showing sensitivity of both induction and deinduction of tat to inhibitors of rna s ... | 1979 | 40116 |
| mammary tumor virus induction by glucocorticoids. characterization of specific transcriptional regulation. | dexamethasone (1,4-pregnadiene-9-fluor-16alpha-methyl-11beta,17alpha,21-triol-3,20-dione), a potent synthetic glucocorticoid, stimulates mouse mammary tumor virus expression 10- to 20-fold in tissue culture cells. this hormone effect was observed at concentrations as low as 1 times 10-10 m and was maximal at 10-7 to 10-8 m. the time course of induction indicated that detectable increases in extracellular viral dna polymerase were first noted 18 to 24 hours following the addition of dexamethasone ... | 1975 | 47326 |
| quantitative estimation of mouse mammary tumor virus (mtv) antigens by radioimmunoassay;. | a radioimmunoassay for the antigens of the mouse mammary tumour virus has been developed. -125iodine-labelling of intact virus [derived from mammary tumours of (c3h times 020)f1 mice] followed by ether extraction and separation of the ether and water layers resulted in a separation of the labelled material into two main groups of antigenic components. the intact labelled material from each group was separated from viral debris and other possible contaminants by affinity chromatography. the antig ... | 1975 | 47846 |
| [biology of mouse rna tumor viruses]. | | 1975 | 48269 |
| polypeptides of the mouse mammary tumor virus. i. characterization of two group-specific antigens. | | 1975 | 49121 |
| competition radioimmunoassay for mason-pfizer monkey virus: comparison with recent isolates. | the major core protein of mason-pfizer monkey virus was purified by deae ion exchange column chromatography and shown to be 27,000 daltons (p27). following the characterization of monospecific antisera prepared against p27, a radioimmunoassay was developed with these reagents and competition experiments were done with come of the recent m-pmy-like isolates as well as with other oncornaviruses. results suggest that three of the viruses tested, ao, x-381 and ftp-1, are similar to m-pmv while j-96 ... | 1975 | 49328 |
| no evidence for particles encapsulating rna-instructed dna polymerase and high molecular weight virus-related rna in herpesvirus induced tumours of non-human primates. | the simultaneous detection test gave no evidence for the presence of rna tumour viruses in herpesvirus induced malignant lymphomas of non-human primates. the 12 tumours tested were obtained from three different monkey species inoculated with herpesvirus saimiri or herpesvirus ateles. particles encapsulating rna-instructed dna polymerase and high mol. wt. virus-related rna were easily demonstrated in tumours of the mouse induced by type-c or type-b oncornaviruses and in human lymphoid cells infec ... | 1975 | 49397 |
| production of mouse mammary tumor virus by cultured cells in the absence and presence of hormones: assay by molecular hybridization. | | 1975 | 49975 |
| blocking of spleen cell activity against target mammary tumor cells by viral antigens. | spleen cells from balb/c females exposed to or neonatally infected with mammary tumor virus (mtv) are cytotoxic to mtv-induced mammary tumor cells in microcytotoxocity assay. this activity can be partially or completely blocked by pretreatment of spleen cells with mtv purified from milk. murine leukemia virus (mulv) has no effect. t cell responses of virgin and multiparous balb/cfc3h females are effectively blocked. non-t cell responses of multiparous balb/cfc3h females or of virgin balb/c femal ... | 1975 | 50346 |
| sequences related to the rna tumor viruses in the rna and dna of human leukemias and lymphomas. | dna-rna hybridization was used to explore whether human neoplasias contain rna molecules having sequence homologies to those of the rna tumor viruses known to cause similar diseases in animals. the pattern of specific rnas found in the human tumors showed a remarkable concordance with the predictions deducible from the animal systems. thus human breast cancer contains rna homologous only to that of the murine mammary tumor virus (mmtv). human leukemias, sarcomas, and lymphomas (including hodgkin ... | 1975 | 51626 |
| detection and characterization of rna tumor virus-specific dna in cells. | rna tumor virus-specific dna in cells can be detected by its capacity to 1) alter the reassociation kinetics of labeled double-stranded product of viral rna-directed dna polymerase; 2) anneal single-stranded dna (cdna) synthesized by viral polymerase; or 3) hybridize labeled viral 70s (genomic) rna. duplexes formed with these procedures can be analyzed for fidelity of base pairing, and the integration of viral dna into the host genome can be established with a simple but stringent technique. we ... | 1975 | 51630 |
| biochemical properties of the bromodeoxyuridine-induced guinea pig virus. | the biophysical and biochemical properties of the virus particles released by guinea pig embryo cells treated with 5-bromo-2'-deoxyuridine (budr) have been compared to those of the b-type mouse mammary tumor virus (mmtv) and the c-type rauscher murine leukemia virus. the high-molecular-weight (60 to 70s) rna of the budr-induced guinea pig virus (gpv) has a molecular weight of 8 x 106 when measred by mixed agarose polyacylamide gel electrophoresis. the virus particles isolated from the tissue cul ... | 1975 | 51933 |
| relationships between membrane antigens of human leukemic cells and oncogenic rna virus structural components. | leukemic cells from all human chronic granulocytic leukemia (cgl) and some acute myelomonocytic leukemia (amml) donors are lysed by rabbit antisera to a purified glycoprotein of friend murine leukemia virus (flv gp71) in a microcytotoxicity assay. these antisera are not cytotoxic to cells from patients with acute myelocytic leukemia (aml), acute lymphocytic leukemia (all), chronic lymphocytic leukemia (cll), or to peripheral blood lymphocytes from normal donors. a goat antiserum to gradient puri ... | 1976 | 53269 |
| experimental infection of a cat kidney cell line with the mouse mammary tumor virus. | a cat kidney cell line, crfk-f2, was successfully inoculated in suspension and in monolayer culture with a purified mouse mammary tumor virus derived from riii milk. the virus produced by the infected cells was identified by immunogluorescence, electron microscopy, and rna-directed dna polymerase assays; it was a b-type virion that did not cross-react with mouse or feline leukemia-sarcoma viruses, had spikes on its envelope, and had a rna-directed dna polymerase reaction that was typical of mous ... | 1976 | 55305 |
| relationships between intracisternal type a and extracellular oncornavirus-like particles produced in murine mopc-460 myeloma cells. | oncornavirus-like particles of the "a" (both intracisternal and intracytoplasmic) and "b" or "c" (extracellular) types are produced by murine mopc-460 myeloma cells. this communication describes a comparative study on tracisternal a and extracellular particles. both types of particles contain an rna-dependent dna polymerase activity, traces of 35s and 70 s rna in addition to larger amounts of degraded rna, and proteins of approximately 76,000 and 45, 000 daltons. the 76,000-dalton proteins from ... | 1976 | 56464 |
| removal of inhibitors against rna-directed dna polymerase activity in human milk. | milk from a number of species (e.g., man, mouse, rat, dog, and cow) contains inhibitors of the rna-directed dna polymerase. when attempts are made to isolate virions from the milk, part of the inhibitors follow the virions in the purification. the amount of inhibitors varies in different milk samples. these inhibitors can probably account for the large discrepancies reported in studies of the presence of oncornaviruses in human milk. phosphatases bound to subcellular particles or fragments seem ... | 1976 | 56990 |
| nucleotide sequence homologies among mouse mammary tumor viruses. | | 1976 | 57670 |
| purification and properties of murine mammary tumor virus dna polymerase. | | 1976 | 58470 |
| removal of inhibitors of particulate reverse transcriptase in human milk. | | 1976 | 58567 |
| [composition of lipids and proteins of two compounds isolated from infected mice: mouse mammary tumor virus and milk fat globule membrane]. | | 1975 | 58612 |
| identification and isolation of the major core protein from the oncornavirus-like particle in human milk. | subviral cores have been prepared from the oncornavirus-like particle found in human milks with the use of phospholipase c and ether or sterox sl. the major protein of these cores has a molecular weight of 27,000 daltons, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. this protein is found in the core fractions of reverse transcriptase-positive milks and is absent in negative milks. it is distributed in sucrose gradients only in those fractions containing cores and r ... | 1976 | 61799 |
| a new class of genetically transmitted retravirus isolated from mus cervicolor. | the cocultivation of spleen cells from the southeast asian mouse, mus cervicolor, with heterologous cell lines has permitted the isolation of a new retravirus (designated m432) that can be transmitted to tissue culture cells of the laboratory mouse, m. musculus. cells infected with m432 contain cytoplasmic type a particles and budding forms with compact,spherical nucleoids; extracellular virions lack surface spikes and have a condensed, central core surrounded by an intermediate line. like other ... | 1976 | 62362 |
| cell culture factors influencing in vitro expression of mouse mammary tumor virus. | several cell culture factors were found to influence in vitro expression of mouse mammary tumor virus (mmtv) in the mouse adenocarcinoma cell line mm5mt/c1. cells were propagated in a variety of commercially available cell culture media to which dexamethasone (dxm) was added as a stimulator of mmtv production. culture seeding density, culture medium type, and glucose concentration each influenced mmtv production when expressed on a per cell basis. maximum cell growth occurred in cultures grown i ... | 1976 | 65318 |
| mouse mammary tumor virus production stimulated by hormones and polyamines in cells grown in semi-synthetic in vitro conditions. | hormonal regulation of mouse mammary tumor virus (mmtv) synthesis was studied in the ccl-51-sf cell subline derived from the sykes' mammary tumor cell line ccl-51 and adapted to grow in semi-synthetic in vitro conditions. the virus was quantitated by measuring the supernatant reverse transcriptase activity in exogenous reaction using poly (ra)-oligo (dt) and poly (rc)-oligo (dg) as template/primers. the cells produced a low but significant amount of virus in the absence of any hormones and serum ... | 1977 | 65340 |
| precursor-product relationship between nonglycosylated polypeptides of a and b particles of mouse mammary tumor virus. | | 1977 | 65829 |
| replication of mouse mammary tumor virus in tissue culture. 1. establishment of a mouse mammary tumor cell line, virus characterization, and quantitation of virus production. | | 1977 | 65833 |
| the structure of the mouse mammary tumor virus: isolation and characterization of the core. | | 1977 | 65834 |
| characterization of a terminal deoxynucleotidyl transferase activity in mouse mammary tumor virus. | | 1977 | 65836 |
| presence of the p27 antigenicity and absence of the gp52 antigenicity and leukemia virus antigens in intracytoplasmic a particles (iap) of mouse mammary tumour origin. | using the ouchterlony immunodiffusion method and indirect immunofluorescence tests on tissue slices the antigenic structure of iap of mouse mammary tumour origin has further been investigated. antisera against iap, mtv-b particles, b particle polypeptide p27 and glycoprotein gp52, and leukemia c-type particles were used in these studies. the most prominent antigen of iap in mammary tumours was found to be identical to the p27 antigen of b particles. this finding was not unexpected in view of rec ... | 1976 | 66045 |
| molecular relationship between h-2 and ml antigens on leukaemia l-1210/v cells. | the molecular relationship between h-2 antigens and mammary leukaemia (ml) antigen at the surface of leukaemic l-1210/v cells was studied by the 'lyso-strip' method. molecules carrying the private specificities of the h-2d haplotype are independent entities in the membrane of the l-1210/v leukaemic cells and are not linked to molecules carrying the 'ml' antigen. | 1977 | 67154 |
| rnase h and rna-directed dna polymerase: associated enzymatic activities of murine mammary tumor virus. | the rna-directed dna polymerase of murine mammary tumor virus, a type b rna tumor virus, was purified sequentially through deae-cellulose, phosphocellulose (step gradient), and phosphocellulose (linear salt gradient) chromatography followed by glycerol sedimentation centrifugation. during all stages of purification, coincident peaks of rna-directed dna polymerase activity, templated by polyribocytidylate-oligodeoxyguanidylate, and rnase h digestion of [3h]polyriboadenylate-polydeoxythymidylate w ... | 1977 | 67221 |
| antigenic relatedness of the dna polymerase of human breast cancer particles to the enzyme of the mason-pfizer monkey virus. | we have previously reported [(ohno, t., sweet, r.w., hu, r., dejak, d. & spiegelman, s. (1977) proc. natl. acad. sci. usa 74, 764-768)] on the purification and characterization of the dna polymerase from human breast cancer particles. its preference for certain synthetic templates and its ability to use a viral rna to fashion a faithful dna transcript identify it as a reverse transcriptase similar to that found in the mouse mammary tumor virus and in the mason-pfizer monkey virus (mpmv). we repo ... | 1977 | 68475 |
| characterization of mouse mammary tumor viruses propagated in heterologous cells. | mouse mammary tumor viruses (mmtv) from three different strains of mice have been used to establish productive infections in feline and mink cell lines. the virions that are released by these cells compete completely in a radioimmunoassay for the major virion surface glycoprotein of mmtv (gp52), thus demonstrating that antigenic determinants of gp52 are viral coded. competitive molecular hybridization studies have shown that the 60 to 70 s rna's of mmtv's propagated in feline cells contain all t ... | 1977 | 68813 |
| cellular immunity to the mammary tumour virus in mice bearing primary mammary tumours. | | 1977 | 69543 |
| characterization of a retravirus isolated from squirrel monkeys. | a new retravirus (smrv) isolated from a squirrel monkey, saimiri sciureus, has an mg2+-dependen reverse transcriptase and a buoyant density of 1.17 g/cm3 in sucrose and 1.21 g/cm3 in cesium chloride, similar to the mouse mammary tumor virus and the mason-pfizer monkey virus. the polypeptide patter of smrv as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis was distinct from the reported polypeptide patterns of known retraviruses. four major polypeptides of molecular weight ... | 1977 | 69728 |
| interferon-mediated inhibition of mouse mammary tumor virus expression in cultured cells. | | 1977 | 70883 |
| identification of the mammary tumor virus envelope glycoprotein (gp52) on mouse mammary epithelial cell surface. | | 1977 | 71144 |
| human studies following animal models of tumorigenesis by oncornaviruses. | similarities have been observed for some time between oncornavirus-induced malignancies in laboratory animals and leukemias and solid tumors in man. particles similar to type c oncornaviruses have been detected by electron microscopy both in cells or plasma from leukemia patients and in solid-tumor human malignancies such as hodgkin's lymphoma, lymphosarcomas, and sarcomas. likewise, particles resembling type b oncornaviruses in shape and appearance have been found in human breast cancer. in nei ... | 1977 | 71181 |
| expression of murine mammary tumor virus-related antigens in human breast carcinoma (mcf-7) cells. | | 1977 | 71356 |
| [virus and cancer]. | | 1977 | 71664 |
| multiple antigenic determinants on the major surface glycoprotein of murine mammary tumor viruses. | the major external protein of murine mammary tumor viruses (mmtvs) is a glycoprotein of molecular weight 52,000 (gp52). we report here that the gp52s of mmtvs from different mouse strains contain both type-specific and group-specific antigenic determinants. competitive radioimmunoassays with externally labeled virion preparations were used to demonstrate that mmtv virions from c3h, riii, and gr mice competed identically in "group-specific" assays but either competed with altered slopes or compet ... | 1977 | 71733 |
| type-specific antigenic determinants on the major external glycoprotein of high- and low-oncogenic murine mammary tumor viruses. | we recently showed that the 52,000-dalton external glycoprotein (gp52) of the highly oncogenic mouse mammary tumor viruses (mmtvs) of riii, gr, and c3h mice contains both type- and group-specific antigenic determinants. this was demonstrated by using a competition radioimmunoassay with 125i-externally labeled virions and antisera to the gp52 of mmtv from riii mice (proc. natl. acad. sci. u.s.a. 74:3564-3568, 1977). we report here that we were able to distinguish between the gp52's of the high-on ... | 1977 | 72161 |
| search for biological markers in breast cancer. | | 1977 | 72388 |
| recovery of concentrated protein samples from sodium dodecyl sulfate-polyacrylamide gels. | | 1977 | 72512 |
| feline malignant mammary tumors. iii. presence of c-particles and intracisternal a-particles and their relationship with feline leukemia virus antigens and rd-114 virus antigens. | thirty-six feline mammary tumors were examined by the electron microscope, and by the indirect immunofluorescence (ifa) test with anti-felv and anti-rd-114 serum. in 11 (30.6%) tumors intracisternal a-particles (iap) were found. one of these tumors contained a few particles with an electron-dense nucleoid in the cisternae of the endoplasmic reticulum. in 7 (19.4%) other tumors c-particles were found and in the remaining 18 (50.0%) no particles at all could be detected. in 11 (30.6%) tumors felv ... | 1977 | 72739 |
| retroviral "terminal deoxynucleotidyl transferase" activity is reverse transcription. | | 1978 | 74894 |
| [rna tumor virus-like particles in hodgkin's disease and in non-hodgkin lymphomas]. | | 1977 | 77100 |
| the biosynthesis of oncovirus proteins. | the patterns of oncovirus protein biosynthesis are essentially similar for avian and mammalian viruses. in each case the four major internal structural proteins are synthesized as a precursor polypeptide of about 75 000 daltons, the product of the gag gene. translation occurs on genome-sized mrna. this polyprotein is cleaved in a series of steps to give the mature proteins. the mechanism and localization of cleavage have not yet been clarified. viral reverse transcriptase, the product of the pol ... | 1978 | 77678 |
| radioimmunoassays that demonstrate type-specific and group-specific antigenic reactivities for the major internal structural protein of murine mammary tumor viruses. | the 28,000-dalton (p28) major structural polypeptide of the mouse mammary tumor virus (mmtv) was isolated and used to develop a highly sensitive and specific radioimmunoassay. under conditions of limiting antibody in competitive binding assays, as little as 50 pg of purified p28, as well as disrupted mmtv virions and mammary tumor extracts, competed specifically with 125i-labeled mmtv p28. the p28 polypeptide was further shown to contain both group-specific and type-specific antigenic determinan ... | 1978 | 77723 |
| specificity and age of appearance of natural immunity to mtv antigens. | | 1978 | 78494 |
| radioimmunologic characterization of rd-114 reverse transcriptase: evolutionary relatedness of mammalian type c viral pol gene products. | | 1978 | 78564 |
| estrogens, estrogen receptors, and biological responses in experimental animals. | | 1977 | 78861 |
| demonstration of components of serum-free culture medium effecting maximum in vitro expression of mouse mammary tumor virus. | by using a chemically defined serum-free (sf) medium for propagation of mm5mtc1 mouse adenocarcinoma cell cultures and clonal derivatives, medium components including hormones, glucose and individual amino acids were evaluated as to modulation of mouse mammary tumor virus (mmtv) porduction. insulin, hydrocortisone and dexamethasone each increased mmtv production on a per cell basis over constitutive expression that occurs in sf medium devoid of hormones. maximum production occurred when all thre ... | 1978 | 78889 |
| early detection of tumor-specific antibodies to mammary carcinoma. | balb/cfc3h female mice which develop mammary tumor virus (mtv)-induced mammary tumors possess not only serun antibodies directed against virus-associated antigens which are expressed on mammary tumor cells but also antibodies directed against antigenic specificities which are unique to each tumor. the possible range of unique specificities is considerable; a survey of serum samples from 18 tumor-bearing females revealed only two which reacted with a tumor-unique specificity of another isologous ... | 1978 | 78910 |
| polyproteins related to the major core protein of mouse mammary tumor virus. | the mouse mammary tumor virus (mumtv) contains several low-molecular-weight proteins which, together with the genomic rna, constitute the core structure of the virion. the most abundant protein in the core is the 27,000-dalton protein (p27), and, by analogy to the type c viruses, this protein probably forms the core shell. in mouse mammary tumor cell lines (gr and mm5mt) producing mumtv the major p57 antigenic specificity resides in a large protein, which migrates in polyacrylamide gels as a dou ... | 1978 | 78987 |
| accelerated growth of mammary tumor cells in normal and athymic mice after treatment in vitro with dexamethasone. | the tumorigenicity of dexamethasone-treated tissue-cultured mammary tumor cells was compared to that of untreated mammary tumor cells. the dexamethasone-induced cells progressed faster in normal syngeneic animals than did untreated mammary tumor cells. the fact that the growth rate differential was also observed in athymic mice suggests that t-lymphocyte-mediated immunity was not a factor in the accelerated progression in vivo of the tumor cells that had been cultured in the presence of dexamet ... | 1978 | 80260 |
| specificity of the simultaneous cell-mediated immune reactivity to riii murine mammary tumor virus glycoprotein 55 and human breast cancer tissues. | | 1978 | 80264 |
| immunohistochemical detection of a cross-reacting virus antigen in mouse mammary tumors and human breast carcinomas. | an indirect immunoperoxidase method was first used to localize mouse mammary tumor virus (mmtv) antigens in paraffin sections of mammary tumors of paris riii and cd8f1 mice. by using the same method, an antigen with cross-reactivity to a group-specific antigen (gp52, a 52,000 dalton glycoprotein) of mmtv was detected in paraffin sections of human breast carcinomas. the specificity of this reaction with antibody against mmtv was examined by absorption of the igg with: a) purified gp52; b) several ... | 1978 | 80418 |
| immunologic methods for the identification of cell types. ii. expression of normal mouse mammary epithelial cell antigens in mammary neoplasia. | mouse mammary epithelial (mme) cell antigens were cell type-specific and were retained, to a large extent, by mme cells after neoplastic transformation. these mme cell antigens were expressed in mammary tumors of balb/c, c3h, grs/a, riii, and is/bi mice tested and were not expressed in tumors whose normal counterpart was other than mammary tissue. they were not dependent on cell culture conditions or on the presence of murine mammary tumor virus; therefore, they can be used in an ubiquitous cell ... | 1978 | 80454 |
| [detection of common antigenic determinants in the envelopes of mammalian type d (mason--pfizer) and type c virions by using the virion precipitation reaction]. | immune sera to mason-pfizer virus (m-pmv) are capable of precipitating type c viruses of mice (nih-mulv, g-mulv, and to a lower degree r-mulv), cats (felv, rd-114), and monkeys (ssv-1, galv, bev). the immune sera to rd-114, bev, ssv-1 and galv viruses can precipitate m-pmv virions. the adsorption analysis suggests that cross-reactions between m-pmv, rd-114, nih-mulv, and g-mulv viruses depend on common virus-specific antigenic determinants in the envelopes of the virions. the relationship betwe ... | 1978 | 80888 |
| effect of 5'-deoxy-5'-s-isobutyl-adenosine (siba) on mouse mammary tumour cells and on the expression of mouse mammary tumour virus. | | 1978 | 81053 |
| detection of cell-mediated immune reactivity of breast cancer patients by the leukocyte adherence inhibition response to mcf-7 extracts. | | 1978 | 81103 |
| immunological characterization of the low-molecular-weight dna binding protein of mouse mammary tumor virus. | p14, a low-molecular-weight mmtv protein previously identified as having dna-binding properties and encoded by the gag region of the mmtv genome, was purified by affinity chromatography on dna-sepharose. immunological characterization of the purified protein showed that mmtv p14 shares no cross-reactivity with gp52, gp36 and p10, antigens associated with the mmtv envelope, nor with p27 antigen found in the virion core. purified mmtv p14 did show cross-reactivity with purified intracytoplasmic a ... | 1978 | 81189 |
| evidence for a precursor-product relationship between intracytoplasmic a particles and mouse mammary tumour virus cores. | this report presents evidence which supports a relationship between intracytoplasmic a particles (cap) and mouse mammary tumour virus (mmtv). three mmtv-specific antigenic determinants in cap (mmtv p27, p14 and p10) uere detected by immunodiffusion. no structural proteins of comparable mol. wt. were found in cap; however, exposure of cap to trypsin resulted in the cleavage of the cap structural proteins to mmtv-like polypeptides. this process was accompanied by the preservation of mmtv-specific ... | 1978 | 81268 |
| presence of a mouse mammary tumor virus-related antigen in human breast carcinoma cells and its absence from normal mammary epithelial cells. | antigen(s) related to the major external glycoprotein (gp52) of mouse mammary tumor virus was detected in the human breast cancer cell line mcf-7. no such antigenic determinants were detectable in normal human mammary epithelial cells. | 1978 | 81881 |
| characterization of a new virus from mus cervicolor immunologically related to the mouse mammary tumor virus. | a virus, similar to the murine mammary tumor viruses (mumtv) of the laboratory mouse mus musculus, was identified in the milk of m. cervicolor popaeus mice. the virus was morphologically indistinguishable from the type-b mumtv and was thus termed mc-mtv. radioimmunoassays for the 52,000-dalton major envelope glycoprotein and the 28,000-dalton major internal protein of mumtv demonstrated that mc-mtv shared some antigenic determinants with both of these mumtv proteins. this reactivity was clearly ... | 1978 | 82634 |
| differential expression of poly(a)-adjacent sequences of mammary tumor virus rna in murine mammary cells. | two dna probes representative of either the entire mouse mammary tumor virus (mmtv) genome or the poly(a)-adjacent sequences at the 3' end of mmtv rna were synthesized with calf thymus dna or oligo(dt) primers, respectively. these probes were used to study the expression of endogenous mmtv sequences in several balb/c mammary tumor cell lines, in normal lactating balb/c tissue, and in a cloned c3h tumor cell line. both probes were characterized with respect to their rates of hybridization with te ... | 1978 | 83648 |
| large-scale production of mouse mammary tumor virus in the absence of endogenous murine leukemia virus. | a system for the large-scale production and purification of mouse mammary tumor virus in the absence of detectable endogenous murine leukemia virus is described. by utilizing the mm5mt/c1 cell line established from an adenocarcinoma of a c3h mouse, the continuous production of over 25,000 liters of mouse mammary tumor virus-containing tissue culture fluids has been achieved. by the strict adherence to well-defined tissue culture conditions, mammary tumor virus production was accomplished without ... | 1979 | 83813 |
| cellular immunity to tumor-associated antigens of transplantable mammary tumors of c3h/hen mice. | | 1979 | 83909 |
| study of the glycolipid composition of the milk fat-globule membrane and the mouse mammary tumour virus prepared from the milk of infected swiss mice [proceedings]. | | 1978 | 84579 |
| a new virion precipitation test for oncovirus envelope antigens which detects common antigenic determinants in mammalian type-c viruses and mason-pfizer monkey virus. | a method for the study of oncovirus envelope antigens was developed, bases on the precipitation of intact virions by a double antibody technique. the amount of precipitated virus was then measured as reverse transcriptase activity. the method was designated the virion precipitation test (vpt). it has been used for titration of antibodies to envelope antigens of oncoviruses. the study of envelop antigens of 11 different oncoviruses permitted their differentiation into the following groups: (1) mu ... | 1979 | 86521 |
| human breast carcinoma antigen is immunologically related to the polypeptide of the group-specific glycoprotein of mouse mammary tumor virus. | we have shown [mesa-tejada, r., keydar, i., ramanarayanan, m., ohno, t., fenoglio, c. & spiegelman, s. (1978) proc. natl. acad. sci. usa 75, 1529--1533] that an antigen immunologically related to gp52, a 52,000-dalton glycoprotein of the mouse mammary tumor virus, can be identified in sections of human breast cancer by means of an indirect immunoperoxidase technique. the specificity of the reaction was established by absorption experiments which revealed that only purified gp52, or material cont ... | 1979 | 88056 |
| virolysis of mouse mammary tumor virus by sera from breast cancer patients. | all type c retroviruses are lysed by human serum in apparently antibody-independent, complement-mediated reactions. in contrast, we have now determined that the mouse mammary tumor virus (mmtv), a type b retrovirus, is not disrupted by normal human serum. mmtv was lysed, however, when rabbit antibody to whole mmtv was added to the serum. by taking advantage of this dependence of mmtv lysis on specific antibody, a virolytic assay was developed, based on the measurement of reverse transcriptase re ... | 1979 | 88736 |
| the purification and characterization of a major glycoprotein of the murine mammary tumor virus. | | 1979 | 88912 |
| characterization of rna-directed dna polymerase in the milk of strain icrc mice. | | 1978 | 89078 |
| mammary tumor viruses. | | 1979 | 89801 |
| purification and properties of rna-dependent dna polymerase from cytoplasmic a-type particles of murine mammary tumor virus. | 1. the rna-dependent dna polymerase associated with cytoplasmic a-type particles of murine mammary tumor virus was isolated to near homogeneity by a procedure which includes dissociation of proteins from rna by centrifugation in a step gradient of cesium chloride, followed by an affinity chromatography on poly(rc)-agarose column. two species of dna polymerase were separated by the chromatography: enzyme i in 0.55 m nacl and enzyme ii in 0.80 m nacl eluate, respectively. 2. the purified dna polym ... | 1979 | 89959 |
| immunological characterization of mouse mammary tumor virus p10 and its presence in mammary tumors and sera of tumor-bearing mice. | mouse mammary tumor virus (mmtv) p10 and gp52 were purified and used as radiolabeled antigens in sensitive radioimmunoassays. these radioimmunoassays were specific for mmtv proteins since detergent-disrupted mmtv from c3h/hen, riii, and gr/n mice gave complete competition, whereas c3h/henf liver extracts and other lysed retroviruses did not. both gp52 and p10 are coded by the viral genome, since mmtv grown in a heterologous cell line (feline kidney cells) competed in these assays. sera from mamm ... | 1979 | 90156 |
| radioimmunoassays for the 36,000-dalton glycoprotein of murine mammary tumor viruses demonstrate type, group, and interspecies determinants. | mouse mammary tumor viruses (mmtvs) contain distinct membrane glycoproteins of 52,000 daltons (gp52) and 36,000 daltons (gp36). we report here the development of new radioimmunoassays for gp36, using gp36 purified by hydrophobic chromatography and gel filtration. these assays demonstrate that gp36 has both type-specific and group-specific antigenic determinants. the virus-coded nature of these determinants was shown by utilizing different mmtvs grown in the same feline cell line. interspecies d ... | 1979 | 90170 |
| simultaneous purification of murine mammary tumor virus structural proteins: analysis of antigenic reactivities of native gp34 by radioimmunocompetition assays. | all the structural proteins (gp47, gp34, p27, p23, p16, and p12) of the murine mammary tumor virus (mumtv) were simultaneously purified utilizing alkylagarose chromatography as the initial fractionation step. least-hydrophobic mumtv polypeptides (p23, p16) and the slightly hydrophobic p27 were separated from moderately hydrophobic proteins gp47 and p12 by passage through octylimino (c(8))-agarose; the gp47 and p12 could be removed from the matrix by elution with ethylene glycol, whereas the most ... | 1979 | 90171 |
| polyribonucleotide inhibition of ribonucleic acid directed deoxyribonucleic acid polymerase of mouse mammary tumor (type b) virus and simian sarcoma (type c) virus. | | 1979 | 90331 |
| virus-like particles and macromolecules in human milk and breast tumors. | relevant data pertaining to present evidence for virus-like particles and virus-related macromolecules in human milk and breast tumors are presented. a critical review and discussion of reported observations concerning virus-related macromolecules will include rna-directed dna polymerase, viral antigens, and rna related to murine mammary tumor virus and/or mason-pfizer monkey virus. from the standpoint of clinical applications, the finding of viral-related antigens in human breast tumors and evi ... | 1979 | 92388 |
| establishment of a c3hf mammary tumor cell line expressing endogenous mouse mammary tumor virus: antigenic and genetic relationships of this virus with highly oncogenic mouse mammary tumor viruses. | a single-cell clone of c3hf mammary tumor cells (clone 14) was developed into a continuous cell line expressing high levels of endogenous mouse mammary tumor virus (mmtv) with less than 0.1% murine leukemia virus expression. comparison of the c3hf mmtv protein profile on sodium dodecyl sulfatepolyacrylamide gel electrophoresis with that of c3h mmtv revealed that the protein content of the two viruses was quite similar. however, oligonucleotide fingerprints obtained of mmtv 70s rna revealed that ... | 1979 | 92576 |
| presence of human milk particle--specific antigens in malignant human breast tumor tissues. | | 1979 | 93088 |
| hormone-responsive genes of the mouse mammary tumor virus. | by optimal hormonal treatment the production of exogenously transmitted mmtv can be stimulated in vitro to different degrees, depending on cultivation conditions and origin of tumor cells. moreover, after appropriate hormonal treatment, endogenous mmtv-y can be rescued from primary cell cultures derived from dimethyl benzanthracene- and hormone-induced c57bl/10 mouse mammary adenocarcinoma, as determined by reverse transcriptase assay, distribution of 3h-uridine-labelled viral particles, immunof ... | 1979 | 94006 |
| a human breast tumor cell line (bt-474) that supports mouse mammary tumor virus replication. | a human breast tumor cell line bt-474 derived from an invasive ductal carcinoma was experimentally infected in vitro with a mouse mammary tumor virus from the tiii strain (riii-mumtv). the virus that replicated in the human cells was characterized as a mouse virus by immunofluorescence, electron microscopy and the presence of a specific rna-directed dna polymerase. the cells themselves were human as per the karyotype and isoenzyme migration patterns. it is concluded that human cells are suscepti ... | 1979 | 94035 |
| mice with spontaneous mammary tumors develop type-specific neutralizing and cytotoxic antibodies against the mouse mammary tumor virus envelope protein gp52. | sera from c3h mammary tumor-bearing mice contain cytotoxic antibodies for mouse mammary tumor virus (mmtv)-producing cells, based on (51)cr release in a complement-dependent serum cytotoxicity assay. the cytotoxic antibodies could be absorbed by purified c3h mmtv gp52 and c3h mmtv-infected cat cells (c3h [mmtv] crfk) containing cell surface mmtv gp52. however, purified mmtv p27 and uninfected crfk cat cells were negative. absorption of the sera with gr (mmtv) crfk cells also removed all of the c ... | 1979 | 94356 |
| mouse mammary tumor virus (mmtv) antigen(s) are present on b lymphocytes of balb/c mice. | immunofluorescence studies using a polyvalent anti-mmtv serum revealed the presence of mmtv antigen(s) on the surface of spleen cells from the low mammary tumor incidence mouse strain balb/ccrgl. upon separation of the splenocytes on nylon-wool columns the populations of cells exhibiting positive fluorescence were nylon-adherent. these cells were considered to be b lymphocytes by the following criteria: presence of surface immunoglobulin (slg), absence of thy-1 antigens, enhanced responses to b- ... | 1979 | 94593 |
| an unlabeled antibody macromolecule technique using hemocyanin for the identification of type b and type c retrovirus envelope and cell surface antigens by correlative fluorescence, transmission electron, and scanning electron microscopy. | the present resolution (75-100 a) of the conventional scanning electron microscope (sem) and its ability to image the surfaces of large numbers of whole cells in situ permit the approach of problems such as viral and cell surface antigen localization by immunological labeling with visual markers. identification of virus and cell surface antigens in situ has been accomplished in indirect reactions by unconjugated markers. hemocyanin (hcy) from whelk, busycon canniculatum, has been developed as an ... | 1979 | 117048 |
| prognostically favorable immunogens of human breast cancer tissue: antigenic similarity to murine mammary tumor virus. | a leukocyte migration procedure was utilized to test cellular hypersensitivity of breast cancer patients' leukocytes to autologous and homologous breast cancer tissues and to murine milk containing murine mammary tumor virus (mumtv). the in vitro responsiveness of the leukocytes and the antigenicity of breast cancer tissues were compared with in vivo prognostically favorable lymphoreticuloendothelial (l-re) responses seen microscopically at the time of mastectomy and with the results of skin win ... | 1975 | 162850 |
| glomerular immune complex deposits associated with mouse mammary tumor. | adult paris r-iii mice with localized mamary tumors were found to have subendothelial glomerular immune complex deposits by electron microscopy and immunofluorescence. in addition to igg adn b-1-c, the glomeruli contained antigenic material that reacted with an antiserum to mouse mamary tumor virus. these findings support the hypothesis that many animals with congenitally or neonatally induced virus-related tumors are not immunologically tolerant to the oncogenic virus. | 1975 | 162869 |
| characteristics of mammary tumor cultures from four mouse strains infected with mammary tumor virus. | the morphology and production of oncornaviruses in primary cell and explant mammary adenocarcinoma cultures derived from c3hf, balb/cniv, balb/cfc3h, and c3h mice were characterized. cultures from the four mouse strains were morphologically similar; they were all epithelial and formed hemicysts and mounds. however, the numbers of cells containing mammary tumor virus (mtv) antigens and the production of cell-free mtv varied greatly among the established cultures. the percentages of mtv-positive c ... | 1975 | 162873 |
| reduced incidence of spontaneous mammary tumors in c3h/he mice after treatment with polyadenylate-polyuridylate. | the effect of treatment with the double-stranded polynucleotide complex polydenylate with polyuridylate [poly(a) with poly(u)] on tumor development in c3h/he mice was evaluated. poly(a) with poly(u) was injected in newborn females, and mice were observed for 380 days. during this experimental period 42 percent of treated mice developed tumors, while the incidence in the control group was 63 percent. this difference was statistically significant. | 1975 | 163037 |
| in vitro detection of immune responses to mtv-induced mammary tumors: qualitative differences in response detected by time studies. | both balb/cfc3h females neonatally infected with mammary tumor virus (mtv) and mtv-free balb/c females possess spleen cells capable of significant activity against target-mtv-induced mammary tumor cells in in vitro microcytotoxicity tests. the responses of the balb/cfc3h and balb/c females are different, however, on the basis of time studies. further, the reactivity characteristic of virgin balb/cfc3h females is increased in parous females, and part of this reactivity is subsequently lost in mul ... | 1975 | 163276 |
| breast cancer: etiology and possible prevention. | | 1975 | 163605 |