Yasuiti Nagano

Enhanced Production of Virus-Inhibiting Factor (Interferon) in Human Diploid Cells by Ultraviolet Irradiation and Temperature Shift-Down after Stimulation with Newcastle Disease Virus

The production of the virus‐inhibiting factor or interferon (IF) was highest in cells incubated at 37 C after inoculation with Newcastle disease (ND) virus and decreased as the incubation temperature was lowered. Shift‐down of incubation temperature to 32 C or 34 C after incubation at 37 C for 4–7 hr enhanced IF production in cell cultures stimulated with ND virus, as compared with cultures incubated continuously at 37 C. Shift‐down to 32 C after incubation at 37 C for 6 hr. was optimal for this enhancement of IF yield. Enhanced IF production was also observed in cell cultures irradiated by ultraviolet light 4–7 hr after stimulation with ND virus.

Disappearance of Terminal Deoxynucleotidyltransferase in Human Malignant T-Lymphoblasts Treated with a Human Alpha Interferon Preparation

Human T‐lymphoblastoid cell lines RPMI 8402, MOLT‐3, and CCRF‐CEM were treated with interferon (IFN) to determine if the treatment would result in the disappearance of cellular terminaldeoxynucleotidyltransferase (TdT), a possible differentiation marker for T‐lymphocytes. Incubation of RPMI 8402 cells in the presence of IFN preparation caused a decrease in the number of TdT‐positive cells and in TdT activity of the cell extract. The inhibition of cell multiplication was dose dependent. The anticellular effect of IFN preparation was cytostatic, not cytocidal. The IFN preparation modified neither the TdT content nor proliferation of MOLT‐3 and CCRF‐CEM cell lines. The effects of IFN preparation thus varied with the cell line.

[37] Induction of interferon by bacterial endotoxin

Publisher Summary Interferon (IF) induced by endotoxin (EII) appears more rapidly in the circulation than virus-induced interferon. EII, however, is not previously stored in the cells, but is synthesized in response to specific stimuli and after synthesis of specific RNA and protein. Continuous cell cultures have not been reported to produce EII. EII is produced by the animal body or by lymphoid cells and macrophages freshly harvested from the animal body. Lower temperatures are appropriate for cells to produce EII in a culture medium than are required for virus-stimulated IF production. The optimum temperature for the stimulation of peritoneal leukocytes with Newcastle disease virus to produce IF in vitro is 40°, but 22-26° is optimal to produce EII. There are various treatments that reduce EII production: injection of corticosteroids, is adrenalectomy, injection of olive oil emulsion, laparotomy, is and infusion of air into the peritoneal cavity. The kinds of treatment will have either no influence or an inhibitory effect on virus-induced IF production.

Modulation by Polymyxin B of the Effects of Interferon on Human Myelogenous Leukemia Cells

Natural and recombinant human interferon‐α (IFN‐α) and ‐γ (IFN‐γ) exert differentiation‐inducing and cytocidal effects in vitro on cells of the human myeloblastic leukemia cell line ML‐2. These activities of IFNs are modulated by polymyxin B (PMB), a cyclic polycationic peptide antibiotic effective on Gram‐negative bacilli. The modulating effect of PMB varies according to the species of IFN, namely, PMB enhances the activities of either natural IFN‐γ or recombinant IFN‐γ, while it inhibits the effects of either natural IFN‐α or recombinant IFN‐α. The cause of this variety in PMB effect on IFNs remains to be clarified.