Studies with Pure Mouse Ehrlich Ascites Tumor Interferons α and β: Patterns of Induction of (2′-5′) (A)_nSynthetase and of a Double-Stranded RNA-Dependent Protein Kinase in Mouse Cells and Human Cells

Abstract

The N-terminal sequences of mouse Ehrlich ascites tumor cell IFN beta (35,000-40,000 daltons) and IFN alpha (20,000 daltons) differ in 18 out of 20 positions. Furthermore, these two IFN species show little immunological cross reactivity. We treated mouse L929 cells and human HeLa S3 cells with essentially pure mouse IFN alpha or IFN beta or both at various concentrations and for various lengths of time. From the treated cells we prepared extracts and compared in these the activities of (2'-5')(A)n synthetase, an enzyme that was earlier shown to be induced by partially purified IFN preparations. The effects of treatment of mouse L929 cells with pure IFN alpha or IFN beta on (2'-5') (A)n accumulation in the cell extracts were very similar both in respect to the dependence on the length of exposure of the cells to the IFNs and on IFN concentration. Treatment with both IFN alpha and IFN beta at concentrations resulting in only partial induction of the enzyme led to an additive rather than to a synergistic effect. The maximal level of enzyme induced was the same in cells treated with high concentrations of IFN alpha or IFN beta or both. Mouse IFN alpha was as active as IFN beta in inducing a double-stranded RNA-dependent protein kinase in mouse L cells. The treatment of HeLa S3 cells with IFN beta did not affect the accumulation of (2'-5') (A)n in their extracts whereas treatment with IFN alpha boosted the accumulation though to a lesser extent than in the case of mouse L cells. These results are in line with the finding that mouse IFN alpha can, but mouse IFN beta cannot convert HeLa S3 cells into the antiviral state and also with the more pronounced homology in N-terminal sequence between mouse IFN alpha and a human (lymphoblastoid) IFN chi than between mouse IFN beta and a human IFN beta.

Receptors for human gamma interferon: binding and crosslinking of 125I-labeled recombinant human gamma interferon to receptors on WISH cells.

“…However, their affinity for IFN is much higher (18)(19)(20)(21)(22) (15,16). The three classes of IFNs (-a, -,/, and -y) also induce the (2'-5')-oligoadenylate synthetase and protein kinase activities (31)(32)(33)(34). If indeed some of the genes induced by the three IFNs are in common, it is of interest how HuIFN-y and HuIFN-a/,B, acting through different receptors, bring about the induction of common genes.…”

Biochemistry of Interferons and Their Actions

“…No difference was detected in the patterns of (2'-5')(A)n synthetase in duction in L929 cells between murine aIFN, ,BIFN, and a 1: 1 mixture of the two IFNs (137). The induction by a 'Y IFN preparation in HeLa cells was reported to be slower than that by an a IFN preparation (188,189).…”

“…As revealed by N-termi nal sequencing one mouse IFN species (designated as aIFN) shares se quence homology with human a IFNs, and a second mouse IFN species (designated as /3 IFN) with human /31 IFN (10). Hybridization patterns of a human a cDNA probe with restriction enzyme fragmented mouse DNA indicate the existence of several mOuse IFN a genes (122), Different mouse IFN species differ greatly in their activity on human cells (136,137) and so do human IFN species in their activity on mouse cells (98,138,139). 6.…”

“…In L929 cells the level of the enzyme starts to increase within 3-5 hr of the beginning of the treatment with a or ,B IFNs and reaches maximal levels by about 15 hr (137). In some cells (e.g.…”

Extracellular Production of Mouse Interferon Beta by the <i>Bacillus subtilis</i> Alpha-Amylase Secretion Vectors: Antiviral Activity and Deduced NH₂-Terminal Amino Acid Sequences of the Secreted Proteins

“…The coding sequence of the mouse IFN-p cDNA showed homologies of 63% at the nu cleotide and 48% at the amino acid sequence level, respectively, with the human interferon-P cDNA [10]. However, it has been re ported that mouse IFN-P has a strong species specificity as compared with mouse IFN-a, and IFN-p was inactive on the HeLa cells [24].…”