Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The purification of a blocking factor from the sera of tumor-bearing mice is described. Whole serum with blocking activity-the ability to inhibit specific cell-mediated anti-tumor immunity in microcytotoxicity tests-was fractionated on immunoadsorbent columns containing Sepharose-bound syngeneic normal mouse immunoglobulins and immunoglobulins from tumor-immune donors. The blocking serum was derived from mice which had carried a transplanted methylocholanthrene-induced sarcoma for 21 to 28 days. Elution of the immunoadsorbents recovered the blocking activity in a single fraction. This fraction was blocking activity in a single fraction. This fraction was radiolabeled and analyzed by SDS gel electrophoresis and Sephadex G-200 column chromatography. The active component of the blocking serum was shown to be a polypeptide of m.w. 56,000. Specificity testing implied that the factor was likely to be either tumor antigen or an antigen-specific suppressor molecule.
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PMID:Purification and partial characterization of a tumor-specific blocking factor from sera of mice with growing chemically induced sarcomas. 6 92

Inbred strain 2 guinea pigs immunized with L2C leukemia cells produced antibodies to L2C cells detected by 125I-protein A assay. L2C-associated tumor antigens were reacted with syngeneic antisera and analyzed by immunoprecipitation and SDS-polyacrylamide gel electrophoresis. These sera recognized idiotypic determinants on surface IgM molecules of L2C cells but did not recognize any determinants on normal strain 2 spleen cells. Thus, determinants on IgM molecular act as tumor-associated antigens in the L2C system and can be detected by syngeneic sera.
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PMID:Identification of a tumor-associated antigen of the guinea pig L2C leukemia by using syngeneic antisera. 7 93

The retrovirus designated RPMI8226V (isolated from human myeloma cells RPMI8226) has been characterized with respect to its morphological, biochemical and immunological properties as well as its propagation in various animal and human cells. The myeloma cells RPMI8226 produce intracytoplasmatic A-type particles and extracellular particles. The extracellular particles have been classified as immature particles with translucent core center, typical mammalian C-type virus particles and C-type particles with intermediate membrane. However, the budded particles in secondarily infected human neoplastic cells contained complete doughnut-shaped nucleoids. This type of budding is rather characteristic for B-type particles. The 3H-uridine labeled RPMI8226 viral particles have a buoyant density 1.17 g/ml in sucrose gradient containing high molecular weight RNA and the distribution of viral structural proteins in SDS-PAGE is characteristic for oncornaviruses. The internal structural proteins according to MW are ranged from 13 000 to 30 000 daltons. The virus contains a magnesium-dependent reverse transcriptase. The cellular homogenate and viral concentrate from RPMI8226 cultures do not react with antibodies against ALSV, MuLV, FeLV, RD114, MP-MV and SiSLV. The only reaction was scored with anti BLV antibodies. However, anti BLV serum inhibiting the reverse transcriptase activity of BLV to 60% does not cross-react with the reverse transcriptase of RPMI8226V. In contrast to BLV concentrates, neither XC nor KC cells show syncytia formation by RPMI8226V. The RPMI8226V replication is restricted to human tumor and normal human glia-like cells. The possible origin of the virus is discussed.
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PMID:The retrovirus particles in human myeloma cells RPMI8226: morphological, biochemical, immunological and infective transmission studies. 8 Jul 55

A human lung tumor-associated antigen was purified from a saline extract of a lung adenocarcinoma. The antigen was demonstrated in extracts of lung adenocarcinoma. The antigen was demonstrated in extracts of lung tumors with the use of an absorbed antiserum by double-diffusion immunoprecipitation. The antiserum did not react with extracts of normal lung or other normal tissues, and the antigen was immunologically distinct from other tumor-associated antigens. Purification was achieved by antibody affinity chromatography and preparative polyacrylamide gel electrophoresis. Isolation procedures were monitored by immunoreactivity with absorbed monospecific antiserum. The antigen was labeled with 125I and judged homogeneous by 1) polyacrylamide gel elecrophoresis in detergent and nondetergent gels, 2) molecular sieve chromatography, 3) ion exchange chromatography, and 4) sucrose gradient sedimentation analysis. A molecular weight of 77,000 was calculated from the s20.w value of 4.24S and from the D20.w value of 5.0X10(-7) cm2/sec. Sodium dodecyl sulfate gel electrophoresis indicated a subunit molecular weight of 42,000. The Stokes radius of the antigen was 40 A and the frictional ratio was 1.42, indicating a nonspherical molecule. The purified radioiodinated antigen could be quantitatively precipitated with specific antiserum.
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PMID:Purification and characterization of a human lung tumor-associated antigen. 8 7

Fibronectin is a glycoprotein found in plasma (cold-insoluble globulin), connective tissues, and cultures of fibroblasts and astroglial cells. This paper describes the identification of fibronectin in human CSF. Fibronectin in CSF was immunologically indistinguishable from the plasma form, as shown by double-diffusion analysis and by radioimmunoassay specific for fibronectin. Fibronectin was isolated from human CSF by affinity chromatography on Sepharose-coupled gelatin and was further analyzed by SDS-polyacrylamide gel electrophoresis. It showed a polypeptide band similar to that of plasma fibronectin. The fibronectin concentration in CSF of 17 neurological outpatients without demonstrable organic lesion in the CNS was 3.0 +/- 1.6 microgram/ml (mean +/- S.D.) which is about 0.6% of total CSF protein. In CSF of 11 MS patients, the concentration was significantly (p less than 0.005) lower (1.6 +/- 0.2 microgram/ml). Of patients with brain tumors, seven had very low levels, three were normal, and two had very high levels. The cause for the low levels in MS and tumor patients is not known.
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PMID:Demonstration of fibronectin in human cerebrospinal fluid. 10 31

The variations of proteins and glycoproteins of Chick embryo fibroblasts are studied during development. This investigation is carried out using polyacrylamide disc gel electrophoresis in SDS. Two glycoproteins of high apparent molecular weight (250,000 and 200,000) undergo quantitative modification: they increase from the 8th to 12th day of development and then remain unchanged to the 16th day. They are cell surface components as suggested by fluorescamine labelling and trypsin sensitivity. The results are discussed in terms of relationship between tumor- and embryo cells.
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PMID:[Electrophoretic profiles of proteins and glycoproteins of chick embryo fibroblasts during development]. 11 22

Encephalomyocarditis (EMC) viral RNA was isolated from purified virus grown in Ehrlich ascites tumor cells. The viral RNA was found to contain polyadenylic acid [poly(A)] regions that were very heterogeneous in length. Chromatography of the EMC viral RNA on oligo(dT)-cellulose columns separated the RNA into three distinct fractions (peaks 1 to 3). Approximately 20% of the EMC viral RNA appeared as peak 1, 40% as peak 2, and 40% as peak 3. The RNA in each fraction appeared to be intact as shown by co-sedimentation with 35S unfractionated EMC viral RNA in SDS-sucrose density gradients. Approximately 95 to 100% of peaks 1 and 3, and 60 to 70% of peak 2, reappeared at the same elution position after rechromatography on oligo(dT)-cellulose. The RNA in peak 1 contained poly(A) with an average length of 16 nucleotides, peak 2 contained poly(A) with an average of 26 nucleotides, and peak 3 contained an average of 74 nucleotides in its poly(A) region. The distribution in the three fractions, as well as the average length of the poly(A) moieties, was relatively unaffected by changes in the cell suspension medium used during infection. Finally, each of the three viral RNA fractions was assayed for biological activity using an infectious RNA assay on L-cell monolayers. Infectivity of the viral RNA was found to increase with poly(A) length, with peak 3 viral RNA being approximately 10 times more infectious than peak 1 viral RNA.
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PMID:Encephalomyocarditis virus RNA: variations in polyadenylic acid content and biological activity. 18 8

High-titer antiserum raised in rats against the tumor (T) antigen of polyoma virus was used to purify the T antigen by the Staphylococcus protein A antibody adsorbent technique. Sodium dodecyl sulfate/polyacrylamide gel electrophoresis allowed the identification of a protein with an apparent molecular weight of 100,000-108,000 as a major component induced in lytically infected mouse cells. In cells infected by ts A mutants this component was temperature sensitive. Several minor components were also observed. In pulse and chase experiments there was a slight decrease in electrophoretic mobility of T antigen during the chase period at the permissive temperature, suggesting that the T antigen is a modified protein. In two lines of transformed cells, the amount of T antigen seemed to be considerably less than in lytically infected cells, but the size of the antigen appeared to be equal.
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PMID:Characterization of polyoma virus T antigen. 19 34

The synthesis and processing of feline leukemia virus (FeLV) polypeptides were studied in a chronically infected feline thymus tumor cell line, F-422, which produces the Rickard strain of FeLV. Immune precipitation with antiserum to FeLV p30 and subsequent sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) were used to isolate intracellular FeLV p30 and possible precursor polypeptides. SDS-PAGE of immune precipitates from cells pulse-labeled for 2.5 min with [35S]methionin revealed the presence of a 60,000-dalton precursor polypeptide (Pp60) as well as a 30,000-dalton polypeptide. When cells were grown in the presence of the proline analogue L-azetidine-2-carboxylic acid, a 70,000-dalton precursor polypeptide (Pp70) was found in addition to Pp60 after a 2.5-min pulse. The cleavage of Pp60 could be partially inhibited by the general protease inhibitor phenyl methyl sulfonyl fluoride (PMSF). This partial inhibition was found to occur only if PMSF was present during pulse-labeling. Intracellular Pp70 and Pp60 and FeLV virion p70, p30, p15, p11, and p10 were subjected to tryptic peptide analysis. The results of this tryptic peptide analysis demonstrated that intracellular Pp70 and virion p70 were identical and that both contained the tryptic peptides of FeLV p30, p15, p11, and p10. Pp60 contained the tryptic peptides of FeLV P30, P15, and P10, but lacked the tryptic peptides of P11. The results of pactamycin gene ordering experiments indicated that the small structural proteins of FeLV are ordered p11-p15-p10-p30. The data indicate that the small structural proteins of FeLV are synthesized as part of a 70,000-dalton precursor. A cleavage scheme for the generation of FeLV p70, p30, p15, p11, and p10 from precursor polypeptides is proposed.
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PMID:Analysis of intracellular feline leukemia virus proteins II. Generation of feline leukemia virus structural proteins from precursor polypeptides. 19 17

Differentially polyadenylated subpopulatons of encephalomyocarditis (EMC) viral RNA were isolated by affinity chromatography on oligodeoxythymidylic acid-cellulose. Translation of these RNA fractions in several in vitro protein-synthesizing systems, isolated from Ehrlich ascites tumor cells, demonstrated that poly(A)+EMC viral RNA was translated two to three times more efficiently than poly(A)-EMC viral RNA. Sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis of the polypetides synthesized by the in vitro system in response to the different RNAs showed no detectable differences in the size or relative amount- of the translational products. mRNA saturation curves indicated that the in vitro systems were stimulated maximally by equivalent amounts of RNA, wheter it be poly(A)-or poly(A)+ EMC viral RNA. Time course experiments showed that the differences in translatability were more pronounced late in the reaction when reinitiation was required, and that by eliminating reinitiation with high salt the apparent effect of poly(A) on translation was diminished. Together, these results suggest that poly(A) may be required for efficient initiation and reinitiation of protein synthesis in the cell-free systems. This interpretation is discussed relative to earlier data.
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PMID:Encephalomyocarditis virus RNA. II. Polyadenylic acid requirement for efficient translation. 19 11


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