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Y Riviere

Publications and source records attributed to Y Riviere.

27 records · Page 2Linked to original sources
PubMed1985

The S RNA segment of lymphocytic choriomeningitis virus codes for the nucleoprotein and glycoproteins 1 and 2.

The lymphocytic choriomeningitis virus (LCMV) genome consists of a large RNA segment and a small RNA segment. The three major structural proteins of this virus are an internal nucleoprotein and two surface glycoproteins. Intertypic reassortants between the Armstrong and WE strains of LCMV were made to map proteins encoded by the LCMV genome segments. Using monoclonal antibodies specific for the nucleoprotein and the glycoproteins of WE and Armstrong, we showed that the small RNA segment of LCMV codes for the three major structural polypeptides.

Animals↗
PubMed1985

Genetic mapping of lymphocytic choriomeningitis virus pathogenicity: virulence in guinea pigs is associated with the L RNA segment.

The Armstrong CA 1371 (ARM) and WE strains of lymphocytic choriomeningitis virus (LCMV) differ in the ability to produce disease in adult guinea pigs. Infection with the ARM strain is not lethal, even at high virus doses (greater than 10,000 PFU), whereas the WE strain causes 100% mortality even at low doses (less than 10 PFU). To determine the genetic basis of this virulence, intertypic reassortants were made between the ARM and WE strains of LCMV. The two reassortants with the genotypes WE/ARM (L segment of WE and S segment of ARM) and ARM/WE (L segment of ARM and S segment of WE) were tested for their pathogenicity in guinea pigs. The ARM/WE reassortant was avirulent like the ARM/ARM parental strain. Minimal viral replication was observed in organs of guinea pigs inoculated with 10(2) or 10(5) PFU of ARM/ARM or ARM/WE, and all animals survived. In contrast, the WE/ARM reassortant was highly virulent like the WE/WE parental strain and killed all of the infected animals. High levels of viral replication were observed in guinea pigs infected with the latter two strains. In contrast to these in vivo observations, both the parental strains and the ARM/WE or WE/ARM reassortants had similar growth potential in cultured guinea pig fibroblasts. Thus, the L RNA segment of LCMV WE is important for viral replication in vivo and is associated with fatal acute disease after infection of adult guinea pigs.

Animals↗
PubMed1983

Enhancement of natural killer cell activity and 2-5A synthetase in mice treated with polyadenylic.polyuridylic acid.

Previous studies have demonstrated that splenic natural killer (NK) cell activity of mice can be efficiently enhanced by polyadenylic.polyuridylic acid [poly(A).poly(U)]. Moreover, inoculation of mice with the duplex leads to the production of interferon (IFN). The NK boosting effect in mice was analyzed in parallel with the assay of an enzyme marker for the production and action of IFN, pppA(2'p5'A)n synthetase (2-5A synthetase). Kinetic studies revealed that splenic mononuclear cells of C3H/He mice inoculated intravenously with 10 micrograms or more of poly(A).poly(U) showed significantly enhanced cytotoxic activity in an in vitro 51Cr-release assay using NK sensitive YAC-1 target cells. Intravenous, intraperitoneal, and intramuscular administration of the duplex into mice were equally effective in obtaining such NK boosting effect. Furthermore, repeated weekly injections of poly(A).poly(U) did not induce resistance against NK boosting in the organisms. The levels of 2-5A synthetase in the organs, particularly spleens, of mice inoculated similarly with poly(A).poly(U) were greatly increased with a dose-dependent pattern. Repeated injections of mice with the duplex at 4-day intervals resulted also in significantly enhanced levels of splenic 2-5A synthetase after each injection. Thus, as a whole, enhanced NK activity accompanied increased levels of 2-5A synthetase in mice treated with poly(A).poly(U).

Adjuvants, Immunologic↗
PubMed1982

Severity of glomerulonephritis induced in different strains of suckling mice by infection with lymphocytic choriomeningitis virus: correlation with amounts of endogenous interferon and circulating immune complexes.

Renal lesions due to neonatal infection with lymphocytic choriomeningitis virus were studied in three different strains of mice known to produce different amounts of viral interferon. Very severe ultrastructural lesions similar to those induced by exogenous interferon were found as early as day 8 in C3H mice which produced the highest amount of interferon. Further studies could not be performed in these mice since all died by day 14. Balb/c mice produced the lowest amount of interferon and had very mild ultrastructural lesions. An intermediate pattern was found in Swiss mice. After 30 days of infection, severe immune complex type glomerulonephritis detectable by light microscopy and immunofluorescence was observed in Swiss mice whereas mild lesions only were found in Balb/c mice. Circulating immune complexes were present in both strains but in greater amounts of Swiss than Balb/c mice. These results suggest that two factors at least are important in the development of glomerulonephritis: interferon produced early in life and the load of circulating immune complexes.

Animals↗
PubMed1982

Induction of interferon by streptococcus pyogenes extracellular products.

Lymphocyte-activating streptococcal exoproteins, which were previously characterized, have been tested for their capacity to induce interferon in vitro. Two out of the 3 different streptococcal fractions, studied on mice splenocytes, were shown to elicit the production of a significant amount of interferon. A large proportion of the interferon detected in the supernatants from mice activated spleen cells was acid-labile interferon. The highest level of interferon titer was obtained with the streptococcal fraction identified as the erythrogenic toxin.

Animals↗
PubMedDate not supplied

HIV F/3' orf encodes a phosphorylated GTP-binding protein resembling an oncogene product.

Apart from the retroviral gag, pol and env the HIV genome contains the F (3' orf) gene which encodes a polypeptide of 206 amino acids which is myristylated at the N-terminal and whose function is unknown. We have expressed the F gene in Escherichia coli and from a recombinant vaccinia virus, VVTGfHIV. The F-protein produced in VVTGfHIV-infected mammalian cells is myristilated, and is phosphorylated by protein kinase C at a residue close to the N-terminus like pp60-src (ref. 5). Purified bacterial F-protein also shows the GTPase, autophosphorylation and GTP-binding activities reported for the ras gene product. Furthermore, we show that expression of F in a CD4+ cell line down-regulates the CD4(T4) antigen. These results suggest that F is important in the pathophysiology of AIDS (acquired immune deficiency syndrome).

Antigens, Differentiation, T-Lymphocyte↗
PubMedDate not supplied

[Salmonella isolated in effluents of Herault stations (author's transl)].

Investigation for Salmonella in the effluents of 97 purification plants has underlined the importance of Salmonella endemy in the county of Herault before and during the summer. The existing systems of purification do not eliminate sufficient pathogenic bacteria from waste waters.

France↗