Interaction of human interferons with immobilized hydrophobic amino acids and dipeptides

Interferons: The pathways of discovery

This article analyzes the conceptual and technological context in which, over a period of 50 years, exploration of the biological and clinical significance of type I interferon has evolved. The elaboration of techniques for production and purification of mouse and human interferons and the establishment of laboratory-size production units have been of crucial importance in this process. Animal experiments have been invaluable for elucidation of mechanisms underlying the in vivo antiviral, anti-tumour and immunomodulatory potential of interferon, but have been of limited help to define the areas of clinical applicability. Proof of principle for applications as they are established today has come from clinical trials performed quite independently of evidence from animal experiments.

Affinity chromatography of primary human amnion interferon

The chromatographic behavior of human amniotic interferon on various affinity chromatography ligands was studied. Most of this interferon bound strongly to bovine plasma albumin-agarose, cibacron blue F3GA-agarose, concanavalin A-agarose and L-tryptophyl-L-tyrosine-omega-carboxyl-pentyl-agarose. After binding most of the interferon activity was eluted only with 50 percent ethylene glycol, showing the high hydrophobicity of this interferon. Smaller quantities could be recovered after phosphate-buffered saline elution or with increased salt concentration. On BPA-omega-carboxy-pentyl-agarose and omega-amino-hexyl-agarose, the majority of the biological activity was found in the break-through fraction (eluted with phosphate buffered saline) while some interferon was displaced with high salt or ethylene glycol. Increasing the salt concentration and lowering the pH was necessary to elute interferon from zinc chelate-agarose. These patterns indicate that human amniotic interferon is similar to human fibroblast (beta) interferon but different from human leukocyte (alpha) interferon. However, the heterogeneity displayed by amniotic interferon on bovine plasma albumin-agarose requires further investigation.

Purification of human lymphoblastoid cell-derived interferon-alpha by controlled-pore glass bead adsorption chromatography and molecular sieving

Human lymphoblastoid cell-derived interferon-alpha has been purified by a combination of chromatography on controlled-pore glass 350, gel filtration on Ultrogel AcA 54 and hydrophobic chromatography on Phenyl-Sepharose CL-4B. Specific activities of greater than 10(7) units/mg have been obtained. Controlled-Pore Glass has the advantages of accommodating large volumes of induced medium in an "in-line" process giving high recoveries of interferon and removing most of any contaminating DNA.

Large scale purification of human fibroblast interferon

Human fibroblast interferon was partially purified, about 4,000-fold, on a chromatographic tandem of columns: concanavalin A-agarose leads to phenyl-agarose, to a specific activity of ca 4 x 10(7). The overall recovery of interferon activity was ca 60%.

Purification of mouse interferon by sequential chromatography

Two schemes for the purification of mouse interferon are described, based on the concerted application of various physicochemical and affinity/adsorption column chromatographic techniques. Mouse interferon was purified to a final specific activity of 1.0--8.0 x 10(8) units/mg when first precipitated with ammonium sulphate and further processed by hydrophobic chromatography and adsorption chromatography on AFFI-Gel 202 and Controlled Pore Glass. It was purified to a final specific activity of 2.5--3.7 x 10(8) units/mg when first precipitated with ammonium sulphate and further processed by gel filtration with Ultrogel AcA 54, ion-exchange chromatography with Carboxymethyl Boi-Gel Agarose, hydrophobic chromatography with AFFI-Gel 202 and adsorption chromatography with Controlled Pore Glass.

Physico-chemical characterization of hamster interferon

The glycoprotein nature of Syrian hamster interferon was tested on several immobilized lectins. The specific retention of a small portion (20%) of interferon activity was observed only on concanavalin A-agarose; Component I of the interferon (not retained) has an apparent molecular weight of 23,500 whereas Component II (retained) is larger, 31,500. The apparent hydrophobicity of Syrian hamster interferon was probed by its chromatography on: (a) straight chain hydrocarbons of varied length; (b) aromatic ligands (aminobenzene, benzylamine, beta-phenylethylamine, gamma-phenyl-propylamine); ligands listed in (a) and (b) were immobilized to cyanogen bromide-activated agarose (isourea linkage); and (c) phenyl-agarose (Phenyl-Sepharose CL-4B), an aromatic ligand immobilized via a 2-hydroxypropyl arm to the agarose (ether linkage).

Fibroblast interferon in man is coded by two loci on separate chromosomes

We have examined viral and poly(rl):poly(rC) induction of interferon synthesis in several human, mouse and Chinese hamster cell lines, and in hybrids derived from the fusion of such cells. We observed species and cell-type differences in inducer effectiveness and in the kinetics of interferon production. In some cases, parental characteristics are preserved in somatic cell hybrids, and in other cases, the expression of the donor phenotype is modulated by the epigenetic state of the recipient cell. Mapping studies in human/mouse and human/Chinese hamster hybrids indicate that there are at least two structural genes for human fibroblast interferon. Chromosomes 2 and 5 each contain genetic information for the synthesis of fibroblast interferon. Gene dosage experiments indicate that one gene is on the long arm of chromosome 2 and another is on the short arm of chromosome 5. Leukocyte interferon genes could not be mapped to these chromosomes, but this negative result could be influenced by the epigenetic state of the hybrid cells.

Human leukocyte interferon purified to homogeneity

One of the species of human interferon produced by incubation of leukocytes with Newcastle disease virus was purified to homogeneity. It exhibited one peak of activity coinciding with a single protein band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

Stabilization of human fibroblast interferon purified on concanavalin A-agarose

Human fibroblast interferon, obtained by chromatography on concanavalin A-agarose, was stable for at least a month in 30--50 per cent ethylene glycol at 4 degrees, --20 degrees, and --70 degrees C. The succinct point of the present finding is that human fibroblast interferon may be stabilized by ethylene glycol alone without the addition of bovine serum albumin and 'back-contamination' of the interferon preparation.

Aging in vitro and large-scale interferon production by 15 new strains of human diploid fibroblasts

To develop resources for large-scale production of human fibroblast interferon, we isolated, cryopreserved, and characterized 15 new strains of human diploid foreskin fibroblasts. Their life spans in vitro ranged from 52 to 72 population doublings. We based the selection of cell strains for mass interferon production on the number of population doublings during which consistently high yields of interferon were obtained after "superinduction" in roller bottles; our data show that aging in vitro leads to significant decline in amounts of interferon produced. In contrast, susceptibility to interferon remains largely unaffected by in vitro senescence. Karyotypic analysis indicated that the best interferon-producing strain, MLD (over 60,000 reference units/ml), has a translocation between chromosomes 5 and 15.

The interaction of mammalian interferons with immobilized cibacron blue F3GA: modulation of binding strength

Mouse, hamster, rabbit, horse, and human interferons bind to immobilized Cibacron Blue F3GA under appropriate solvent conditions. Three forms of the immobilized ligand have been investigated: Cibacron Blue F3GA-Sepharose 4B, Blue Dextran-Sepharose 4B and Blue Sepharose CL-6B. The strength of binding of an interferon depends critically on the sorbent: Cibacron Blue F3GA-Sepharose 4B is the weakest in the series and Blue Sepharose CL-6B the strongest. The use of Blue Dextran-Sepharose 4B--a sorbent of intermediate binding properties--allows the complete separation of hamster, mouse and human fibroblast interferons in a single chromatographic step. Indeed, both the resolution, as well as the recovery, of those interferons is complete--regardless of the relative complexity of the chromatographed preparation (containing either crude or purified interferons). Thus, these ligands should prove of considerable use when a facile chromatographic evaluation, both qualitative and quantitative of mammalian interferons is required.