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Biomedical subjects

F Besançon

Publications and source records attributed to F Besançon.

At least 55 records · Page 3Linked to original sources
PubMed1980

Mouse fibroblast (type I) and immune (type II) interferons: pronounced differences in affinity for gangliosides and in antiviral and antigrowth effects on mouse leukemia L-1210R cells.

Different interferons can be obtained from the same animal species depending on the cells and (or) the inducers used. Interferons of type I and type II differ not only antigenically but also in molecular weight and stability at low pH. We have investigated whether mouse type I and type II interferons also differ in properties relating to their biological action. We present evidence which suggests that the molecular mechanism leading to antiviral and antigrowth effects induced by both types of interferon in susceptible cells must differ in at least one important step. Antiviral and antigrowth activities of type I but not of type II interferon are both inhibited when gangliosides are added to cell cultures together with the interferon. Whereas type I interferon strongly binds to ganglioside affinity columns and can be eluted with solutions of N-acetylneuraminyllactose, type II interferon passes through such columns unretarded. L-1210 mouse leukemia cells (L-1210S) respond equally well to antiviral and antigrowth activities of type I and type II interferons. Type I interferon-resistant L-1210 cells (L-1210R), derived from L-1210S cells after continuous culture in the presence of mouse fibroblast interferon, lack antiviral and antigrowth response to mouse type I interferon [Gresser, I., Bandu, H.T. & Brouty-Boyé, D. (1974) J. Natl. Cancer Inst. 52, 553-559]. However, these cells display the same sensitivity toward type II interferon as do the parent L-1210S cells from which they were derived and respond equally well to its antiviral and antigrowth activities.

Animals↗
PubMed1977

Membrane receptors for interferon.

Specific cell membrane receptors for interferon have been postulated based on a variety of different observations, such as the following: trypsin treatment of monkey-mouse hybrid cells preferentially destroys sensitivity to primate interferon (9); syngeneic mice immunized with human-mouse hybrid cells develop surface-directed antibodies, which only block antiviral action of human interferon (24); interferon covalently bound to Sepharose beads retains its antiviral activity despite the fact that diameters of the beads are several times those of the cells (1,10,19); cells challenged with polyl:C to produce interferon do not develop resistance to viral infection in the presence of interferon antiserum (30). Interferon has a strong and specific affinity for the carbohydrate side chain of cell membrane gangliosides. Preincubation of Sepharose-bound interferon with gangliosides inhibits antiviral activity in the following order of potency: GM2 greater than or equal to GTl greater than GMl greater than or equal to GDla (3). Derivatives of GM2 lacking either terminal N-acetyl-galactosamine or terminal N-acetyl-neuraminic acid are not (or very little) inhibitory; in addition, binding to gangliosides is reversed by N-acetyl-neuraminyl-lactose, the trisaccharide common to all gangliosides. These data clearly demonstrate interferon's specificity for the carbohydrate moiety of the ganglioside molecule (6). Phaeseolus vulgaris lectin, which blocks antiviral action of interferon (4), also prevents binding of interferon to ganglioside-Sepharose affinity columns (2). Many substances of known affinity for gangliosides likewise inhibit action of interferon. These include cholera (15) and tetanus toxins (2), thyrotropin (5,23) and human chorionic gonadotropin (5). Although a more general effect on the state of the membrane or on cellular metabolism by these substances cannot be ruled out, competition for interferon binding sites appears to be the most plausible explanation. Increased sensitivity of certain transformed cells to interferon upon uptake of exogenous gangliosides not only supports the concept that these glycolipids are involved in binding of interferon to the membrane, but furthermore points to the importance of interferon-ganglioside interaction for triggering of the antiviral response (29).

Cell Membrane↗
PubMed1977

[Trial of immunodiffusion on cellulose acetate. Application to the estimation of immunoglobulins A and serum transferrin. Results in alcoholism and cirrhosis (author's transl)].

The authors propose electro-immunodiffusion on cellulose acetate instead of agar gel. This simple, rapid and economical method was applied to the estimation of serum immunoglobulins A and transferrin. The following results were obtained for the IgA/transferrin ratio in 108 cases: Normal: 0.87 +/- 0.29; alcoholics without proved cirrhosis: 1.61 +/- 0.95; alcoholic cirrhosis: 3.36 +/- 2.30. The interest of this determination in detection is increased by this simple test.

Acetates↗
PubMed1973

Mechanism of interferon uptake in parental and somatic monkey-mouse hybrid cells.

Dose-response curves of interferons in different sensitive cells are regularly sigmoidal. In somatic monkey-mouse hybrid cells, however, a significant decrease in the slope of the curve for primate interferon was observed, while the dose-response effect was unaltered for mouse interferon. High concentrations of primate interferon were 10- to 100-times less effective in hybrid clones than in parental monkey CV-1 cells; at low concentrations the antiviral effect was 10- to 20-times higher in hybrid clones than in the parental cells. The receptor(s) for primate interferon located on the cell membrane was destroyed by trypsin but not by EDTA. Similarly, acid pH inactivated these receptor sites. We, thus, postulate that the antiviral effect is, at least partially, related to the amount of interferon taken up by the cells. Uptake could be conditioned by active cooperation of two cell-specific factors: a receptor and an activator. The activator might be missing or inactivated for primate interferon in the hybrid cells. We suggest that the putative antiviral protein is not cell-species specific, and that information for its synthesis in the hybrid cells might be located on a mouse rather than a monkey chromosome.

Animals↗