Biological properties of human interferon beta 1 synthesized in recombinant bacteria

Purification of human antibodies from transgenic corn using aqueous two-phase systems

A recombinant human antibody expressed in corn was purified using aqueous two-phase extraction. The antibody was an immunoglobulin G fully unglycosylated. Using systems of different compositions and/or pHs in each of one or two partitioning stages followed by one more stage in which the antibody was precipitated at the liquid/liquid interface facilitated the removal of different impurities in each stage. The best system yields a product 72% pure (22-fold purification) with a yield of 49%. The optimum extraction was done in two partitioning stages followed by an interfacial precipitation stage using poly(ethylene)glycol/potassium phosphate systems. NaCl was added to the first stage to eliminate large molecular weight impurities. The pH in the first stage was kept at 6 but a pH of 8 was used in the second stage and in the precipitation stage.

[Expression of human interferon beta in the mammary gland of transgenic rabbits]

A biotechnological system for the production of human beta interferon was developed on the basis of a hybrid gene constructed from the coding sequence of the beta interferon gene inserted into the first exon of the sheep beta lactoglobulin gene. It is intended for the expression of human beta interferon in mammary glands of transgenic animals. Two lines of transgenic rabbits were obtained using the hybrid gene. The tissue specificity of the expression of the transgene and the frequency of its inheritance in the first and second generations were studied. The activity of interferon was 2.2 x 10(4)-7.2 x 10(4) IU per milliliter of milk of transgenic female rabbits. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2008, vol. 34, no. 2; see also http:// www.maik.ru.

Biological standardization of human interferon beta: establishment of a replacement world health organization international biological standard for human glycosylated interferon beta

Human interferon beta (IFN-beta) has been developed as a major biotherapeutic agent for the treatment of multiple sclerosis. Since World Health Organization (WHO) international standards (IS) for IFN-beta were established several years prior to the development of clinical grade IFN-beta products, a number of scientific issues with regard to the biological standardisation of natural and recombinant IFN-beta products have emerged. In order to address these issues, an international collaborative study to evaluate WHO IS and candidate international standards (CIS) of IFN-beta was instigated by the National Institute for Biological Standards and Control (NIBSC) in 2000 and was carried out in the succeeding year. Sixteen expert laboratories from 8 countries worldwide participated in the study. They performed titrations on 8 different IFN-beta preparations, including IS and new CIS, in a variety of mainly antiviral- but also including some antiproliferative- and reporter gene-assays, and contributed raw data from these assays to NIBSC for statistical analysis and calculation of potencies. While both intra- and inter-laboratory variation of potency estimates was evident, overall validity of the study as a whole was clearly shown by comparison of two pairs of internal coded duplicates, which gave the expected relative potency of 1 and the lowest inter-laboratory variability of potency estimates in all assay types. The CIS containing Chinese hamster ovary (CHO) cell- or human fibroblast-derived, glycosylated, IFN-beta gave similar low inter-laboratory variation in potency estimates one to another as the coded duplicates, which was significantly less than to the 2nd WHO IS of IFN-beta, human fibroblast-derived, Gb23-902-531. One of these CIS, designated 00/572, containing CHO cell-derived IFN-beta and formulated with both bovine casein and human serum albumin, could be assigned a potency, consistent for all assay types, of 40,000 international units (IU) per ampoule relative to the IU of the 2nd IS of IFN-beta, Gb23-902-531. Other CIS containing glycosylated IFN-beta, either CHO cell- or human-fibroblast-derived, could also be assigned potency values that were continuous with the IU of Gb23-902-531 and 00/572. However, greater inter-laboratory variations in estimates were evident from comparisons of Gb23-902-531 or 00/572 with either the 1st IS for E. coli-derived, non-glycosylated, IFN-beta with serine substitution at position 17 (IFN-beta Ser 17 mutein), Gxb02-901-535, or with a CIS (00/574) containing IFN-beta Ser 17 mutein. Indeed, variations in potency estimates for preparations containing IFN-beta Ser 17 mutein were sufficiently large to indicate that assays could distinguish preparations of IFN-beta Ser 17 mutein from preparations of glycosylated IFN-beta. Thus, neither the 2nd IS of IFN-beta, Gb23-902-531, containing fibroblast-derived IFN-beta, nor CIS, 00/572, containing CHO cell-derived IFN-beta, was appropriate for standardisation of preparations of IFN-beta Ser 17 mutein. Conversely, neither the IS of IFN-beta Ser 17 mutein, Gxb02-901-535, or a CIS of IFN-beta Ser 17 mutein, 00/574, was appropriate for the standardisation of preparations of glycosylated IFN-beta. CIS 00/572, containing CHO cell-derived, glycosylated IFN-beta, was clearly shown to be suitable to serve as a primary standard for glycosylated forms of IFN-beta, especially clinical grade IFN-beta-1a products. It was further shown to exhibit high thermal and long-term stability. Since the CHO cell-derived IFN-beta used for preparation of 00/572 was of a greater purity than the IFN-beta used for the 2nd IS of IFN-beta, Gb23-902-531, it was recommended by the WHO Informal Consultation on the Standardisation of Cytokines, Growth Factors and Other Endocrinological Substances, which met in October 2003, that 00/572 should replace Gb23-902-531 as the IS for glycosylated IFN-beta. This recommendation was accepted by the WHO Expert Committee on Biological Standardization (ECBS) at its annual meeting in November 2003 and 00/572 was established as the 3rd IS for human glycosylated IFN-beta with an assigned potency of 40,000 IU. As this study identified no advantage to replacing the existing 1st IS for IFN-beta Ser 17 mutein, Gxb02-901-535, WHO ECBS accepted that this should continue to serve as the IS for this material.

N-linked glycan structures of mouse interferon-β produced by Bombyx mori larvae

The full-length mouse interferon-beta (mIFN-beta) cDNA, including the secretion signal peptide coding region under control of the polyhedrin promoter, was introduced into Bombyx mori nucleopolyhedrovirus (BmNPV). Recombinant mIFN-beta (rmIFN-beta) was accumulated in the haemolymph of infected silkworm larvae. Western blot analysis showed isoforms of rmIFN-beta, suggesting that rmIFN-beta is glycosylated. The glycan structures of purified rmIFN-beta were determined. The N-glycans were liberated by hydrazinolysis and the resulting oligosaccharides were labeled with 2-aminopyridine. The pyridylaminated (PA) glycans were purified by gel filtration, reversed-phase HPLC, and size-fractionation HPLC. The structures of the PA-sugar chains were identified by a combination of two-dimensional PA-sugar chain mapping, MS analysis, and exoglycosidase digestions.

Evidence from transgenic mice that interferon-beta may be involved in the onset of diabetes mellitus

A number of cytokines have been shown to alter the function of pancreatic beta-cells and thus might be involved in the development of type 1 diabetes. Interferon-beta (IFN-beta) expression is induced in epithelial cells by several viruses, and it has been detected in islets of type 1 diabetic patients. Here we show that treatment of isolated mouse islets with this cytokine was able to alter insulin secretion in vitro. To study whether IFN-beta alters beta-cell function in vivo and leads to diabetes, we have developed transgenic mice (C57BL6/SJL) expressing IFN-beta in beta-cells. These mice showed functional alterations in islets and impaired glucose-stimulated insulin secretion. Transgenic animals presented mild hyperglycemia, hypoinsulinemia, hypertriglyceridemia, and altered glucose tolerance test, all features of a prediabetic state. However, they developed overt diabetes, with lymphocytic infiltration of the islets, when treated with low doses of streptozotocin, which did not induce diabetes in control mice. In addition, about 9% of the transgenic mice obtained from the N3 back-cross to outbred albino CD-1 mice spontaneously developed severe hyperglycemia and hypoinsulinemia and showed mononuclear infiltration of the islets. These results suggest that IFN-beta may be involved in the onset of type 1 diabetes when combined with either an additional factor or a susceptible genetic background.

Purification of recombinant human interferon-beta by immobilized antisense peptides

Synthetic antisense peptides encoded in the antisense strands of DNA corresponding to the 1-14, 42-54 and 103-115 fragments of the human interferon-beta sequence were applied in the purification of recombinant human interferon-beta from a mammalian cell culture. The protein fragments were selected on the basis of their computer-predicted exposure on the surface of the protein. The antisense peptides were synthetized by the solid-phase method directly on the resin used as the stationary phase in affinity chromatography. All the tested antisense peptides showed a selective affinity for human interferon-beta, permitting a ten-fold purification of the protein.

Enhanced viral resistance in transgenic mice expressing the human beta 1 interferon

Recombinant plasmids pMTIF-beta 1A and pMTIF-beta 1B were constructed by fusing the metallothionein I promoter-regulatory region to the human beta 1 interferon (HuIFN-beta 1) gene. These linearized fusion genes were then introduced into mouse germ lines by zygote microinjection. The chromosomal integration and the germ line transmission of the injected DNA sequences in the resulting transgenic mice were detected by DNA dot blot and Southern transfer hybridizations. The sera of at least two strains of metallothionein/HuIFN transgenic mice were found to protect human WISH cells against vesicular stomatitis virus infection, and this activity could be neutralized by preincubation with anti-HuIFN-beta 1 antibody. These transgenic mice demonstrated significantly enhanced resistance to pseudorabies virus compared with nontransgenic mice when inoculated with pseudorabies virus. The level of resistance seemed to correlate with the concentrations of HuIFN-beta 1 in serum. These transgenic mice may be used as models to study IFN-induced responses and may serve as prototypes to generate disease-resistant animals.

Purification and carbohydrate structure of natural murine interferon-beta

Mouse interferon-beta (Mu-INF-beta) induced in C-243 cells with Newcastle disease virus was purified in four steps including ammonium sulfate fractionation. DEAE-cellulose, monoclonal Mu-IFN-beta antibody affinity and Mono-S cation-exchange chromatographies. Specific activity of the purified Mu-IFN-beta ranged over 1.1-1.4 X 10(9) NIH units/mg protein. This preparation was submitted to pronase digestion and gel on Fractogel TSK HW-40. The permethylated and acetylated glycopeptide fraction was analyzed by chemical-ionization (ammonia) mass spectrometry. The major glycopeptide is composed of Gal, Man, GlcNAc and NeuAc with a molar ratio of 2.0:3.6:3.4:0.5. The GLC pattern of methyl derivatives obtained by methanolysis and acetylation of fully methylated glycopeptide identified 2,3,4,6-tetra-O-methylgalactose; 3,4,6-tri-O-methyl-mannose; 2,3,4- and 2,4,6-tri-O-methylgalactose; 2,4,di-O-methyl mannose and 3,6-di-O-methylglucosamine. These results when compared with data on N-glycans suggest the following structure for the carbohydrate moiety of Mu-INF-beta: (formula; see text).

Chemical mutagenesis of human interferon-beta: construction, expression in E. coli, and biological activity of sodium bisulfite-induced mutations

A series of modified human interferon-beta (IFN-beta) genes was produced by sodium bisulfite treatment of the IFN-beta gene cloned in M13. A library of mutated sequences was generated from which subgenomic fragments containing one or a small number of coding alterations were isolated and substituted into the IFN-beta gene in an E. coli expression vector. A number of modified genes and their expression products were evaluated. In several instances levels of expression and biological activity profiles are altered compared to the parental gene product. A number of key amino acids can be identified, whose substitutions have marked effects on biological activity of IFN-beta.

Novel modified beta-interferons: gene cloning, expression, and biological activity in bacterial extracts

A series of novel, modified interferons based on the structure of human beta-interferon have been expressed in Escherichia coli. Modified interferon genes were constructed from sequences derived from the natural beta-interferon gene, a synthetic beta-interferon gene, or a specific combination of the two. A total of 23 out of the 25 novel interferons exhibited antiviral (AV) and antiproliferative (AP) activity which varied from 3 to 230% and 8 to 490% of the values for beta-interferon, respectively. None of the novel interferons had only AV or AP activity, although one had a much reduced ratio of AV/AP activity compared with beta-interferon. Substitution of beta-interferon amino acids 2-7 or 28-46 resulted in interferons with significantly increased AP activity on Daudi lymphoblastoid cells (four- to fivefold). All the novel interferons except two with modifications in the 82-105 region reacted with a neutralizing beta-interferon monoclonal antibody.

The antiproliferative activity of interferons assayed by measuring growth medium color changes related to cell number

A simple colorimetric assay for estimating cell numbers has been developed based on the observation that the indicator color in cell culture medium is proportional to viable cell number. The assay is performed in multiwell plates to take advantage of the rapid color measurement and computerized data handling capabilities of multiwell scanning spectrophotometers. Since no centrifugation or washing steps are involved, the technique is particularly useful for cells that grow in suspension, although it is equally applicable to monolayer cultures. The assay was developed to measure the antiproliferative activity of interferons on Daudi lymphoblastoid cells but could equally well be applied to other cell growth inhibition or stimulation assays.

Monoclonal antibodies to human beta-interferon produced by adoptive transfer in irradiated mice

Three murine anti-human beta-interferon (IFN-beta) monoclonal antibodies have been isolated following adoptive transfer of immune spleen cells. Adoptive transfer was used to increase the specific efficiency of the fusion. These antibodies have been used to define two epitopes on IFN-beta; the antiviral, antiproliferative, and immunomodulatory effects of IFN-beta are associated with one of these epitopes.