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Biomedical subjects

E Falcoff

Publications and source records attributed to E Falcoff.

At least 91 records · Page 5Linked to original sources
PubMed1973

Double-stranded ribonucleic acid from Mengo virus: production, characterization, and interferon-inducing and antiviral activities in comparison with polyriboinosinic-polyribocytidylic acid.

Mengo virus double-stranded ribonucleic acid (dsRNA) was obtained on a semi-industrial scale from infected cultures of BHK-21 cells grown in suspension. Yield of the extraction and purification operations was small (about 22 mg from 10(11) cells in a 100-liter culture). Physicochemical characterization of this dsRNA gave an estimated molecular weight close to 4 x 10(6), a density of 1.59 (similar to that of the poliovirus dsRNA), and a thermal transition midpoint of 94 C. This product was a little more toxic for the mouse, by the intravenous route, than polyriboinosinic . polyribocytidylic acid (poly I:C) and strictly comparable in this respect to poliovirus dsRNA. The interferon-inducing capacity in the mouse and the antiviral activities in the mouse (infected with encephalomyocarditis, Semliki Forest, influenza, foot-and-mouth disease, and murine hepatitis viruses) and in the rabbit (Shope fibroma virus) of the ultraviolet light-inactivated product were practically identical, on a quantitative basis, with those of poly I:C. In vitro and in vivo experiments showed the dsRNA from Mengo virus to be slightly but significantly more resistant than poly I:C to the inactivating effect of human serum.

Animals↗
PubMed1973

Correlation between the antiviral effect of interferon treatment and the inhibition of in vitro mRNA translation in noninfected L cells.

When noninfected L-cell suspension cultures are treated with interferon (specific activities superior to 10(6) reference units per mg of protein), the cell-free cytoplasmic extracts obtained are inactive for the translation of exogenous natural mRNAs. The dose-response curve shows that comparable amounts of interferon are required to produce a 50% reduction of Mengo virus multiplication in vivo and Mengo RNA translation in vitro. With higher doses of interferon, Mengo RNA translation is completely abolished, while poly U translation and endogenous protein synthesis are only slightly affected. The inactivation of Mengo RNA translation is reversible; after removal of interferon, normal translation activity is regained together with the ability to support Mengo virus multiplication. Fractionation of the cell-free extracts shows that the effect is localized in the fraction which can be washed off the ribosomes by high salt. These results establish that interferon induces a block in genetic translation in noninfected L cells.

Animals↗