Tumor specific surface antigen in the culture medium of a rat cell line transformed by Rous sarcoma virus]

TSSA is detected on transformed cells by a mixed hemadsorption reaction. The medium of cultures of Rat cells transformed by Rous sarcoma virus (Prague strain, sub-group C) contains a soluble factor which specifically inhibits this reaction. This factor thus possesses the antigenic activity of TSSA which is associated with the presence of a component of molecular weight 42,000 by polyacrylamide gel electrophoresis.     

Expression of an antigen associated with Gross virus on the surfaces of murine cells producing an oncornavirus from the radioleukemia of C57BL/6 mice]

A leukemogenic viral complex was demonstrated in cultures of 13-3 C cell line derived from a C57BL/6, radiation leukemia virus (RadLV-Rs) induced tumor. Both 13-3C and leukemic cells induced in C57BL/6 mice by 13-3C virus carry a cell surface antigen associated with Gross leukemia virus (GCSAa). These findings point to a close similarity between these antigens and those of murine endogenous ecotropic viruses.     

Sedimentation behaviour of the avian tumor virus group specific antigen from the BAI strain,a virus associated myeloblast cell

Zusammenfassung BAI Virus Stamm A und mit diesem Virus infizierte Myeloblastzellen haben ein gemeinsames, gruppenspezifisches Antigen. Das aus dem Virus abgetrennte Antigen wurde mit dem aus den Zellen herausgelösten im Saccharose-Dichtegradienten verglichen. Sowohl für das Virus wie für das Zellantigen wurde der gleiche Sedimentationswert erhalten.

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This work was done while the author was at Duke University Medical Center, Durham (N.C., USA)     

Demonstration of antigen associated with human breast cancers]

The insoluble pellet of human mammary carcinomas was solubilized by an acid buffer. Antiserum prepared with this acidosoluble fraction, after suitable absorption gave one precipitin line with the immunizing extracts: this line is different from those given by the tumor associated antigens actually known. The same antiserum reacted only with sections of human mammary carcinomas by immunofluorescence . It did not stain sections of normal mammary glands or benign mammary diseases. Reactivity with cancers of other organs was absent or doubtful. Hence it is likely that an antigen associated to human mammary carcinomas was characterized.     

Serological identification of an antigen associated with acute lymphoid leukemia]

Using as references a lymphoblastoid cell line established from the pleural effusion of a lymphosarcoma patient and the corresponding autochtonous reactive serum, absorption typing assays resulted in the identification of a cell surface antigen associated with acute lymphoid leukaemia. This antigen, provisionally termed PON, may also be demonstrated on the cells of some acute myelomonocytic leukaemias and lymphosarcomas.     

Cellular control of the tick-borne virus antigen production in persistently infected cell culture

Summary The influence of inhibition or stimulation of cellular DNA synthesis on tick-borne virus antigen production in persistently infected cell culture was studied. Either mitomycin C or cytosine-arabinoside caused cessation of antigen-containing cell number increase. Stimulation of cellular DNA synthesis by growth medium change increased the level of antigen-containing cells. When HEp-2-Sof culture was synchronized, a correlation was observed between the entrance of cells into DNA synthesis phase and the increase of proportion of antigen-containing cells.     

Cytotoxicity of human peripheral blood T-lymphocyte clones activated by hepatitis B virus surface antigen

Summary The present studies examined the cytotoxic activities of peripheral blood lymphocytes (PBL) from volunteers with (sero-positive) and without (sero-negative) circulating antibodies to hepatitis B virus surface antigen before and 30 days after vaccination with hepatitis B virus surface antigen (HBsAg). Long-term culture of monospecific hepatitis B surface (HBsAg)-responsive T-lymphocytes were isolated and grown in large numbers. The mechanism of T-cell mediated cytolysis, and the identification of the carbohydrate determinants on the surface of these effector cells responsible for the killing effect, are being examined.     

Cytotoxicity of human peripheral blood T-lymphocyte clones activated by hepatitis B virus surface antigen

The present studies examined the cytotoxic activities of peripheral blood lymphocytes (PBL) from volunteers with (sero-positive) and without (sero-negative) circulating antibodies to hepatitis B virus surface antigen before and 30 days after vaccination with hepatitis B virus surface antigen (HBsAg). Long-term culture of monospecific hepatitis B surface (HBsAg)-responsive T-lymphocytes were isolated and grown in large numbers. The mechanism of T-cell mediated cytolysis, and the identification of the carbohydrate determinants on the surface of these effector cells responsible for the killing effect, are being examined.     

Cellular control of the tick-borne virus antigen production in persistently infected cell culture.

The influence of inhibition or stimulation of cellular DNA synthesis on tick-borne virus antigen production in persistently infected cell culture was studied. Either mitomycin C or cytosine-arabinoside caused cessation of antigen-containing cell number increase. Stimulation of cellular DNA synthesis by growth medium change increased the level of antigen-containing cells. When HEp-2-Sof culture was synchronized, a correlation was observed between the entrance of cells into DNA synthesis phase and the increase of proportion of antigen-containing cells.     

A new method permitting the quantitative determination of virus present in surface waters]

With a 34% efficiency, not related to the amount of viruses, a simple and inexpensive apparatus allows quantitative recovery of enteroviruses from river-water.     

Detection and localization of a ribonuclease activity associated with vaccinia virus]

A ribonuclease associated with vaccinia virus can be detected when reduced concentrations of nucleotides are used for an in vitro RNA synthesis assay. The non-viral origin of this ribonuclease may be inferred from its external location and from its variable activity on different purified virus stocks. The detection of this ribonuclease activity on purified virus grown without foetal Calf serum may suggest that this enzyme is of cellular origin.     

Absence of relationship between erythrocyte and viral antigen expressed on the surface of chick erythrocytes]

Anti-gs antisera were tested on embryo and adult Chick erythrocytes. Specific immunsera directed against Chick embryo or adult erythrocyte antigens have been tested on Hamster cell lines infected with the Rous virus. Results demonstrate that the erythrocyte and viral antigens are different.     

Compared expression of murine plasmacytoma associated virus in tumor cells and in mouse embryo cells]

A DNA complementary to the viral genome of C-type particles produced by a Mouse myeloma derived cell line (MF2 cell line) was synthesized. This cDNA was used as a probe to study the viral genome expression among the total RNA and the poly (A)-rich RNA extracted from the MF2 and Balb/c embryonic cells. As evidenced by molecular hybridization experiments, the presence of at least one endogenous Balb/c virus in the MF2 virus stocks is suggested. In the productive cells, the viral RNA sequences are expressed in the poly (A)-rich RNA fraction.     

Ultrastructural localization of newcastle disease virus surface antigen in infected Hela cells as revealed by an enzyme-labelled antibody method

Zusammenfassung Nach indirekter peroxidasekonjugierter Antikörpermethode wurden elektronenmikroskopisch mit Newcastle-Disease-Virus infizierte HeLa-Zellen geprüft, und in den frühen Infektionsstadien an den Ribosomen des endoplasmatischen Retikulums solcher Zellen und in den späten Infektionsstadien an den «Spikes» des spriessenden Viruskörperchens das Antigen der Virusoberflächen gezeigt.     

Murine type C endogenous virus expression in murine 129 teratocarcinoma cell line]

Murine type C viral information is detectable in the cellular genome of both differentiated and undifferentiated cell lines derived from 129 Mouse teratocarcinoma. Cytoplasmic RNA expression which is negligible in differentiated cells, is significantly higher in multipotential undifferentiated cells. Furthermore it was observed that in vitro differentiation of multipotent cells leads to a decrease of this expression.     

Ultrastructural aspects of the cell fusion induced by Visna virus on sheep choroid plexus cell in culture]

Sheep choroid plexus cells infected with low multiplicities of infection of Visna Virus were stellate and had long and thin processes containing filaments and forming cytoplasmic bridges between adjacent cells. Enlargement of the bridges resulted in the formation of multinucleated cells. Some glycoproteins were clustered on filaments outside the cell. The cytoplasmic changes showed : an intensive protein synthesis; numerous mitochondria closely associated with filaments and some lysosomes and numerous vesicules near the plasma membrane.     

The replication of a xenotropic murine C type virus in some mammalian cells. Definition of a specific antigen]

The use of our mink cell line maintained in vitro infected with the murine xenotropic AT 124 virus, and that of a (W/Fu x bn) f1 rat anti-124 serum allow us to define a new cell surface antigen specific of murine xenotropic type C viruses.