Activity of human recombinant and lymphoblastoid interferons in human and heterologous cell lines

Suppression of late asthmatic response by low-dose oral administration of interferon-beta in the guinea pig model of asthma

We investigated the anti-asthmatic effects of low-dose oral and subcutaneous administration of interferon-beta (IFN-beta) on an ovalbumin (OVA)-sensitized and challenged guinea pig model of asthma. Subcutaneous administration of IFN-beta suppressed the eosinophil infiltration by 14.2% of the control and the respiratory resistance (Rrs) by 58.2% at 2.0 MIU/kg. Oral administration of IFN-beta inhibited the late asthmatic response (LAR) by suppressing the increase of Rrs by 29% of the control at 1 IU/ml and the eosinophil infiltration into the trachea and lung by 34.6% at the optimum dosage of 10 IU/ml. Both subcutaneous and oral administration could not inhibit the early asthmatic response (EAR). Additionally we found 2',5'-oligoadenylate synthetase (2',5'-OAS) induction by low-dose oral administration (LDOA) of IFN-beta to the same extent as by subcutaneous administration in whole blood in vivo. These data suggest that LDOA of IFN-beta would have some clinical benefit for patients with asthma.

Effect of recombinant hybrid human interferon on replication and morphogenesis of HSV-1 in monkey cells

Human recombinant alpha interferon, A/D, significantly reduced the replication and cell fusion induced by herpes simplex virus type 1 in monkey cells. Thin-section electron microscopy of interferon-treated monkey cells showed distinct assembly of nucleocapsids within the nucleus. Analysis of virus-specific proteins by the immunoblot technique confirmed that A/D interferon had no significant effect on the expression of major nucleocapsid proteins, although the expression of glycoproteins B and D was reduced in interferon-treated cells. The possibility of an interferon-induced block at a late stage in virus morphogenesis is discussed.

[Sensitivity of different cell lines to interferons: the relative antiviral activity as a function of the interferon subtype]

The phenomenon that rHuIFN-alpha1(D) displays an apparently higher antiviral activity when assayed on bovine cells as compared to human cell lines was applied to the elucidation of the nature of recombinant HuIFN prepared in our institute. These investigations were carried out by using a microtitre test, which defines biological activity as the IFN concentration leading to 50% inhibition of the cytopathic effect of vesicular stomatitis virus (VSV). In addition, the ability of IFN to diminish the reproduction of infectious viruses was monitored. The two methods yielded similar results. With bovine cells, antiviral activities of the same order of magnitude were observed, regardless of the interferon types applied, i.e. rHuIFN-alpha 1, rHuIFN-alpha 2 and human leukocyte interferon. On human fibroblasts, however, rHuIFN-alpha 1 had an apparently 45 to 165 times lower activity than the other two interferons. On human WISH cells, the differences in apparent activity between the respective IFNs were even greater, with factors of up to 212 fold being observed. Still more distinctive were the effects on murine L 929 cells where an antiviral effect could be confirmed only for rHuIFN-alpha 1 whereas the other two interferons proved completely inactive.

Recombinant human interferon-alpha A treatment of an experimental cutaneous herpes simplex virus type 1 infection of guinea pigs

Recombinant human interferon-alpha A (rIFN-alpha A) was evaluated for therapeutic efficacy against an experimental dorsal cutaneous herpes simplex virus type 1 (HSV-1) infection of guinea pigs. Human IFN has activity in this species. Animals were treated either systemically (i.m.) or topically with different formulations of rIFN-alpha A. Therapy was initiated 24 h before (-24 h), 30 min after (+0.5 h), or 24 h following (+24 h) virus inoculation, and treatment was continued for 3-5 days. Efficacy was evaluated on day 4 following infection. Treatment with rIFN-alpha A given systemically beginning at -24 h was effective, reducing lesion number, total lesion area, and lesion virus titer by 64%, 85%, and 98% respectively (p less than 0.001). Efficacy diminished with delay in initiation of i.m. therapy. Topical rIFN-alpha A formulations were generally ineffective, showing only a marginal effect with therapy initiated -24 h or +0.5 h and no effect when treatment was delayed to +24 h. In summary, rIFN-alpha A is effective against cutaneous HSV-1 infection in this model if therapy is initiated prophylactically and if drug delivery is assured by systemic injection. Topical application of rIFN-alpha A showed little therapeutic effect. The large molecular weight of IFN likely retards its percutaneous delivery.

The preclinical development of Roferon-A

Interferon alfa-2a (Roferon-A, Hoffmann-La Roche Inc., Nutley, NJ) is identical to one of approximately 15 subtypes of interferon alpha made by human leukocytes and is produced in bacteria using recombinant DNA techniques. In its antiviral, antiproliferative, and immunomodulatory activities it is similar to leukocyte interferon alpha. These activities are species-restricted and have been demonstrable, thus far, only in humans, certain other primates, bovines, and guinea pigs or cells derived therefrom. The possibility that the toxicity of interferon alfa-2a would also be species-restricted appears to have been confirmed by results obtained thus far. Toxicological studies in rats, mice and several species of monkeys have failed to indicate the side effects that have been observed in humans. However, studies in species in which interferon alfa-2a is active and in others in which it is not, have revealed similar pharmacokinetics and elimination mechanisms.

[Interferon sensitivity of various cell lines]

An economic assay to determine the yield of interferon is necessary for the induction, production and purification of interferon. Using the inhibition of cytopathic effect of vesicular stomatitis virus in a microtitre system, we compared the susceptibility of different cell lines against an internal IFN alpha standard obtained from Sendai virus-induced human leukocytes. Human fibroblasts carrying trisomy G 21 and bovine MDBK cells showed the highest sensitivity followed by normal human fibroblasts. Human RH kidney cells exhibited a susceptibility similar to that of human WISH amnion cells frequently used by others. The human amnion cell line FL and monkey Vero kidney cells, as described here, were unsuitable for the determination of IFN yields.