Synergistic effect of interferon-gamma and tumor necrosis factor-alpha on antiviral activity and (2'-5') oligo (A) synthetase induction in a myelomonocytic cell line.

TNF was not observed to have an antiviral effect on either HL60 or U937 cells. However, it did significantly enhance interferon (IFN)-gamma-mediated antiviral activity in U937 cells. Treatment of U937 cells with IFN-gamma enhanced (2'-5') oligo (A) synthetase activity (2.

Increased production of interferon gamma and tumor necrosis factor precedes clinical manifestation in multiple sclerosis: do cytokines trigger off exacerbations?

We have carried out a longitudinal study of interferon (IFN) and tumor necrosis factor (TNF) using a whole-blood mitogen stimulation assay in 20 multiple sclerosis (MS) patients and in a healthy control group. We set up individual profiles and the results were quite constant for each individual, both in healthy donors and in the patients in remission. Before exacerbations, however, we found an increase of IFN-gamma and TNF production preceding clinical symptoms by a maximum of 2 weeks.

Characterization of antibodies against recombinant HuIFN-gamma produced by hybridoma cells.

Balbc/c mice were immunized with purified recombinant E. coli-derived human gamma-interferon (HuIFN-gamma). Their spleen cells were fused with a mouse myeloma cell line (Sp2/0).

Helper activity for antibody synthesis encoded by mRNA extracted from human peripheral blood mononuclear cells.

Translation products in Xenopus laevis of mRNA from human peripheral blood mononuclear cells were tested for their capacity to replace T cells in the anti-SRBC response of nude spleen cells. When the starting material came from PHA or FCS-stimulated lymphocytes, the translated lymphokines, displaying such a B cell helper activity were found to be encoded by mRNA sedimenting at 6-7S and 13S on a sucrose density gradient. 6-7S mRNA from control, non-stimulated lymphocytes was also able to code for B cell helper activity.

Translation of mRNA from phytohemagglutinin-stimulated human lymphocytes: characterization of interferon mRNAs.

Human lymphocytes obtained by cytapheresis were stimulated in spinner culture conditions by nonpurified PHA in order to study the production of gamma interferon, and the characterization of IFN-gamma mRNA. Titers of interferon prepared in 0.6 to 4 1 batches, varied in 20 preparations from 8,000 to 32,000 units/ml.

Production of antibodies against mouse immune T (type II) interferon and their neutralizing properties.

An antiserum to immune T-type mouse interferon was prepared in rabbits by repeated injections of interferon, induced by phytohaemagglutinin (PHA) in mouse spleen cells and purified to 1 X 10(5) units/mg protein. The antiserum neutralized mouse interferons synthesized in vitro in response to several T mitogens and Brucella organisms, and also the type II interferon present in the serum of BCG-sensitized mice after an injection of the specific antigen, tuberculin. All these interferons are thus antigenically related; they are also all unstable at pH 2.

Immune interferon induced by phytohemagglutinin in nude mouse spleen cells.

Phytohemagglutinin is able to trigger interferon synthesis in spleen cell cultures from nude (nu/nu) mice as effectively as in splenic cell cultures from haired, control (nu/+), thymus-bearing mice. A minor theta-bearing cell population present in the spleen of nude mice appears essential to phytohemagglutinin interferon production, although cooperating cells are also required. The properties of nude mouse phytohemagglutinin interferon are indistinguishable from those displayed by the interferon induced in thymus-bearing mouse spleen cell cultures.

Affinity chromatographic analysis of murine interferons induced by viruses and by T and B cell stimulants.

Murine interferons induced by viruses and by non-viral substances such as lectins, tilorone, lipopolysaccharide and Brucella have been analysed by affinity chromatography on a column of Sepharose coupled to antiviral interferon antibodies. The results reported here suggest that virus and B-cell stimulants induced interferons which are antigenically related and that T cell-dependent mitogens induce and "interferon like" molecule which appears to be antigenically and physiocochemically different.

Inhibitory effect of interferon on DNA and RNA synthesis in murine spleen cells stimulated by lectins.

Spleen cells from mice inoculated with partially purified preparations of interferon (Sp. Act. 1 X 10(7) i.