Production and purification of human leukocyte interferon

A Low-Molecular-Weight Compound Derived from Human Leukocytes Determines a Bactericidal Activity of the Interferon Preparation

The aim of this study was to characterize the structure and mode of action of antimicrobials derived from a commercial preparation of alfa-interferon. By combination of semi-preparative/analytical reversed-phase high-performance liquid chromatography, we isolated and purified a novel active substance based on carbohydrate with a complex of amino acids, which determines antimicrobial property of commercial preparation of interferon. A size-exclusion chromatography was performed and LC/ESI-MS revealed molecular masses of active substance were in the range of 180-249 Da. Edman sequencing identified phenylthiohydantoin (PTH) derivatives which consisted a set of preliminary (Asp, Glu, Gly, and Ala) and minor amino acids (Leu and Thr) at equimolar ratio. Thus, the purified active substance is a compound containing the complex of amino acids connected with carbohydrate background and called leucidin. Leucidin demonstrated antimicrobial activity against the model Escherichia coli (E. coli) K12 strain at a minimal inhibitory concentration of 20 μg mL^-1. The revealed antimicrobial mechanism of action is associated with violation of the bacterial cell wall leading to a SOS response and bacterial autolysis. Despite the preliminary nature of the results, obtained data allowed us to discover the previously unknown leukocyte-derived antimicrobial molecules.

Intrathecal administration of human leukocyte interferon to a patient with subacute sclerosing panencephalitis

An eight-year-old boy with subacute sclerosing panencephalitis was treated with human leukocyte interferon (HuIFN-alpha) by intravenous and intrathecal injections. We observed some remarkable improvements in his clinical course.

Purification of human leukocyte interferon alpha by carboxymethyl controlled pore glass bead chromatography

Human leukocyte-derived alpha interferon [HuIFN-alpha(Le)] has been purified and/or concentrated on Carboxymethyl derivatized Controlled Pore Glass (CML-CPG240) beads. These glass beads adsorb HuIFN-alpha(Le) efficiently at acid pH and at physiological ionic strengths. Elution of HuIFN-alpha(Le) may be accomplished by several methods. Using buffers at relatively high ionic strengths (approximately 0.6 M) and pH values ranging from 2.6 to 6.9 for elution, preparations with specific activities of 10(5)-10(6) IU/mg were obtained with approximately 90 percent recoveries. Alternatively, using elution buffers at the same high ionic strength and at pH values ranging from 7.0 to 8.0, five-fold or better concentration and complete recovery of crude HuIFN-alpha(Le) were achieved. The resulting preparations were suitable for direct application to an antibody affinity chromatography column.

Antitumor effect of human leukocyte interferon on human osteosarcoma transplanted into nude mice

We studied the effect of human leukocyte interferon (HuIFN-alpha) on a human osteosarcoma (OS-OH) transplanted and passed serially in athymic mice. The growth of OS-OH was strikingly inhibited by HuIFN-alpha (50,000 IU/mouse), regardless of whether the interferon treatment was initiated 24 hr after tumor inoculation or 2 weeks later, when tumors had grown to an appreciable size (4-6 mm). The antitumor effect of HuIFN-alpha was found to be dose-dependent and a daily administration of HuIFN-alpha (50,000 IU/mouse) all but completely arrested the tumor growth.

Induction of human leukocyte interferon by heat-treated poly I: poly C

Synthetic double stranded RNA (poly I: poly C) was prepared from polyinosinic acid (poly I) and polycytidylic acid (poly C) by heat-treated followed by gradual cooling, and was used for induction of human leukocyte interferon (IFN). When poly I: poly C solution was heated at 37 - 65 degrees C for 30 minutes, high activity of human IFN (10,000 - 60,000 i. u./ml) was obtained. In this system, the optimum molecular weight of poly I: poly C to induce IFN was 12.6 - 17.6 S. The properties of induced IFN were heat- and acid- stable, and it was neutralized with anti-IFN alpha serum. So, it was confirmed that it was IFN alpha.

Human cytotoxic T lymphocytes (CTL) induced by phytohemagglutinin: conditions for CTL generation and effect of interferon

The present study demonstrates that human peripheral blood mononuclear cells (PMC) can be stimulated in vitro to become cytotoxic T lymphocytes (CTL) by PHA. A significant cytotoxic activity of PMC was detected 48 hr after the culture initiation in the presence of 5 micrograms/ml of PHA and the peak level of the activity was obtained by culturing PMC for 72 hr. The cytotoxic cells require the presence of PHA as a cell agglutinin for the expression of their cytotoxic activity. The effector cells mediating the activity were identified as T lymphocytes by E-rosette fractionation of PMC. In this system, removal of carbonyl iron phagocytosed or attached cells from PMC did not abrogate CTL generation of PMC. In addition, human alpha-interferon did not augment CTL generation or expression of their activity. Although the target cells employed were sensitive to natural killer (NK) cells, the effector cells induced by PHA did not seem to have any relation to the NK cells. The present study may provide a useful tool to analyze for precursors of killer T cells.

Elimination of polynucleotide-induced hyporeactivity in mice treated with interferon and antitumor therapy

Polyriboinosinic-polyribocytidylic acid (poly I:C) (100 microgram) induced hyporeactivity to interferon production 24, 48 and 72 hr after the injection. This hyporeactivity was eliminated by the injection of mouse brain interferon (more than 10,000 IU) 3 hr prior to the second injection of poly I:C. Even the hyporeactivity caused by the repeated administration of poly I:C was eliminated when interferon was injected 3 hr before each administration of poly I:C. It was surmised that one of the causes for the elimination of hyporeactivity may be the priming effect effect of interferon in mice. By utilizing the eliminating effect which interferon has on the hyporeactivity caused by poly I:C, the synergistically suppressive effect of interferon and poly I:C on the mortality and tumor growth in the neuroblastoma-bearing mice was found. These results suggest that the combined use of interferon and interferon-inducer may be applicable to cancers or viral diseases in humans.

Increased nitroblue tetrazolium dye reduction by human neutrophils stimulated by interferon in vitro

Human leukocyte interferon enhanced nitroblue tetrazolium dye (NBT) reduction by human neutrophils (PMNs). Increase in NBT reduction paralleled increase in interferon dose. When human leukocyte interferon was heated to 60 C or 80 C for 30 min, both the antiviral activity and the effect on NBT reduction decreased. Human leukocyte interferon neutralized with anti-human leukocyte interferon serum showed no effect on NBT reduction. A human fibroblast interferon preparation also enhanced NBT reduction. The species dependency of interferon was shown in NBT reduction as well as in antiviral activity.

Effect of interferon on chronic infection of human cells by xenotropic type-C viruses

Different preparations of human interferon inhibit virus production in human cells chronically infected by a variety of type-C xenotropic viruses. Some of these viruses have been incriminated in the development of leukemia in primates. The characteristics of blocking of viral multiplication are similar to those described for the effect of mouse interferon on ecotropic viruses. The amount of free virus in culture supernatants is strongly decreased while intracellular protein p30 stays unchanged or is slightly increased. On the other hand, the inhibitory effect is reversible. The withdrawal of interferon results in a rapid increase in virus production as detectable in supernatant fluids. In the light of these results it is suggested that human interferon might be useful in the treatment of some blood malignancies suspected of being related to infection with xenotropic type-C viruses.

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.

Antigenic properties and heterospecific antiviral activities of human leukocyte interferon species

Human interferon obtained in peripheral leukocytes was purified approximately 1000-fold by affinity chromatography on anti-leukocyte interferon globulins coupled to Sepharose 4B, and by filtration on SDS-Sephadex G-100. The interferon was subsequently resolved into two molecular species by adsorption chromatography on SDS-hydroxylapatite. The two species which were eluted at different phosphate molarities from hydroxylapatite, could also be distinguished on the basis of electric charge properties and they migrated at different rates in SDS-polyacrylamide gels. Crossneutralization tests with monospecific rabbit anti-leukocyte and anti-fibroblast interferon sera revealed that the two species possessed leukocyte interferon-specific antigenic determinants. Both were immunogenic in mice and they were neutralized to a comparable degree by antisera against either component. A variable degree of antiviral activity was expressed by both interferon components in bovine, porcine and murine cells. However, the two interferon species were equally active in this respect, and the protective effects exhibited in homologous and heterologous cell cultures were similarly susceptible to reduction by beta-mercapto-ethanol. We conclude that the two molecular species of human leukocyte interferon are biologically similar.

Electron microscopic observations on the lesions of herpes zoster with topical application of interferon

The lesions of herpes zoster in three patients were investigated electron microscopically before and after topical application of interferon. In the blister, on the 5th to 7th day after its formation, the following were seen: acantholytic cells with virus particles in the nucleus and cytoplasm, multinucleated cells derived from keratinocytes, edematous and degenerated keratinocytes containing virus particles and tonofibrillar materials, macrophages with many large vacuoles, neutrophils, lymphocytes and Langerhans's cells. After the first application of interferon, the findings for keratinocytes were the same as those of before application and keratinocytes were frequently found adjacent to macrophages. The macrophages were large and had numerons large vacuoles in the cytoplasm. After the second application of interferon, virus particles were often seen in the vacuoles of the macrophages in comparison with that before application. In the cytoplasm of macrophages, acantholytic keratinocytes and tonofibrillar materials were phagocytized. Many virus particles were seen in the vacuoles of some acantholytic keratinocytes. It was concluded from these findings that the macrophages accelerated the phagocytotic activity of the virus particles.

Inhibition of macrophage migration by virus-induced interferon preparations

It was found that a preparation of mouse L cell interferon induced by Newcastle disease virus (NDV) possessed not only interferon activity but also inhibitory activity upon migration of guinea pig peritoneal macrophages (MIF activity). These activities were also observed in a preparation of human leukocyte interferon induced by NDV. The interferon and MIF activities shared common characteristics in the dose response, time course of in vitro production, thermal stability, sensitivity to trypsin and periodate, and elution pattern in CM-Sephadex column chromatography. However, gel filtration pattern with Sephadex G-100 showed two separate peaks. Fractions collected from the first peak, corresponding to a molecular weight of about 45 000, had only the MIF activity, while those collected from the second peak, corresponding to a molecular weight of about 30 000, had both the interferon and MIF activities. A preparation of mouse brain interferon induced by Japanese encephalitis virus had a much weaker MIF activity than the L cell interferon, although these preparations were equal in interferon activity (5000 units/ml).