Ability of Orally Administered IFN-α-Containing Transgenic Potato Extracts to InhibitListeria monocytogenesInfection

Plant-based oral vaccines against zoonotic and non-zoonotic diseases

The shared diseases between animals and humans are known as zoonotic diseases and spread infectious diseases among humans. Zoonotic diseases are not only a major burden to livestock industry but also threaten humans accounting for >60% cases of human illness. About 75% of emerging infectious diseases in humans have been reported to originate from zoonotic pathogens. Because antibiotics are frequently used to protect livestock from bacterial diseases, the development of antibiotic-resistant strains of epidemic and zoonotic pathogens is now a major concern. Live attenuated and killed vaccines are the only option to control these infectious diseases and this approach has been used since 1890. However, major problems with this approach include high cost and injectable vaccines is impractical for >20 billion poultry animals or fish in aquaculture. Plants offer an attractive and affordable platform for vaccines against animal diseases because of their low cost, and they are free of attenuated pathogens and cold chain requirement. Therefore, several plant-based vaccines against human and animals diseases have been developed recently that undergo clinical and regulatory approval. Plant-based vaccines serve as ideal booster vaccines that could eliminate multiple boosters of attenuated bacteria or viruses, but requirement of injectable priming with adjuvant is a current limitation. So, new approaches like oral vaccines are needed to overcome this challenge. In this review, we discuss the progress made in plant-based vaccines against zoonotic or other animal diseases and future challenges in advancing this field.

Low-dose interferon-α treatment improves survival and inflammatory responses in a mouse model of fulminant acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is accompanied by severe lung inflammation induced by various diseases. Despite the severity of symptoms, therapeutic strategies for this pathologic condition are still poorly developed. Interferon (IFN)-α is well known as an antiviral cytokine and low-dose IFN-α has been reported to show antiinflammatory effects. Therefore, we investigated how this cytokine affected ARDS in a mouse model. C57BL/6 mice received sequential intratracheal administration of α-galactosylceramide (α-GalCer) and lipopolysaccharide (LPS), which resulted in the development of fulminant ARDS. These mice were then treated intranasally with IFN-α and their survival, lung weight, pathological findings, and cytokine production were evaluated. Administration of low-dose IFN-α prolonged survival of fulminant ARDS mice, but higher doses of IFN-α did not. Histological analysis showed that low-dose IFN-α treatment improved findings of diffuse alveolar damage in fulminant ARDS mice, which was associated with reduction in the wet/dry (W/D) lung weight ratio. Furthermore, IFN-γ production in the lungs was significantly reduced in IFN-α-treated mice, compared with control mice, but tumor necrosis factor (TNF)-α production was almost equivalent for both groups. Low-dose IFN-α shows antiinflammatory and therapeutic effects in a mouse model of fulminant ARDS, and reduced production of IFN-γ in the lung may be involved in the beneficial effect of this treatment.

Ability of orally administered IFN-α4 to inhibit naturally occurring gingival inflammation in dogs

It has been reported that type I interferons (IFN-α/β) play an important role in innate immune responses against viral and bacterial infections. In this study, we used and examined naturally occurred canine periodontal disease to show the therapeutic efficacy of low dose oral administration (LDOA) of canine IFN-α subtype 4 (CaIFN-α4). We administered purified recombinant CaIFN-α4 expressed in a baculovirus system to dogs with or without gingival inflammation. We found that LDOA of CaIFN-α4 reduce periodontopathic bacterial counts. LDOA induced improvement of naturally occurring gingival inflammation, and reduction of the stress marker responses was also observed after LDOA. These results suggest that LDOA of CaIFN-α4 has effectiveness for improvement of naturally occurring gingival inflammation in dogs.

Transient expression of chicken alpha interferon gene in lettuce

We investigated the possibility of producing chicken alpha interferon (ChIFN-alpha) in transgenic plants. The cDNA encoding ChIFN-alpha was introduced into lettuce (Lactuca sativa L.) plants by using an agro-infiltration transient expression system. The ChIFN-alpha gene was correctly transcribed and translated in the lettuce plants according to RT-PCR and ELISA assays. Recombinant protein exhibited antiviral activity in vitro by inhibition of vesicular stomatitis virus (VSV) replication on chicken embryonic fibroblast (CEF). The results demonstrate that biologically active avian cytokine with potential pharmaceutical applications could be expressed in transgenic lettuce plants and that it is possible to generate interferon protein in forage plants for preventing infectious diseases of poultry.

Efficient production of canine interferon-alpha in silkworm Bombyx mori by use of a BmNPV/Bac-to-Bac expression system

We exploited the silkworm Bombyx mori for the production of recombinant canine interferon-alpha (CaIFN-alpha). The recombinant baculovirus harboring canine interferon gene was rapidly generated by the BmNPV/Bac-to-Bac system that was recently developed. In B. mori-derived cell lines, the expression of the recombinant protein reached maximal levels around 72-96 h post-infection. For the isolation of the expressed recombinant protein from B. mori larvae, the whole bodies of the infected larvae were homogenized, and the expressed protein was purified by affinity chromatography. Based on the fact that the recombinant CaIFN-alpha showed two bands on the sodium dodecyl sulfate polyacrylamide gel electrophoresis pattern, the expressed protein was thought to be glycosylated. The rCaIFN-alpha yield was about 528 microg per larva, showing that the expression in silkworm was successful. Furthermore, the recombinant protein was proven to be able to inhibit the infection of Madin-Darby canine kidney cells by the vesicular stomatitis virus, indicating that it is biologically active in vitro. The method established in this study provides an efficient way to produce a large amount of CaIFN-alpha and paves the way for further utilization of this protein as a therapeutic agent or vaccine adjuvant in dogs.

STAT1 regulates IFN-alpha beta- and IFN-gamma-dependent control of infection with Chlamydia pneumoniae by nonhemopoietic cells

STAT1 mediates signaling in response to IFN-alpha, -beta, and -gamma, cytokines required for protective immunity against several viral, bacterial, and eukaryotic pathogens. The protective role of STAT1 in the control of intranasal infection with the obligate intracellular bacterium Chlamydia pneumoniae was analyzed. IFN-gamma-/- or IFN-gamma receptor (R)-/- mice were highly susceptible to infection with C. pneumoniae. We found that STAT1-/- mice were even more susceptible to C. pneumoniae than IFN-gamma-/- or IFN-gammaR-/- mice. Phosphorylation of STAT1 was detected in the lungs of C. pneumoniae-infected wild-type, IFN-gammaR-/-, and IFN-alphabetaR-/- mice, but not in mice lacking both IFN-alphabetaR and IFN-gammaR. In line with this, IFN-alphabetaR-/-/IFN-gammaR-/- mice showed increased susceptibility to infection compared with IFN-gammaR-/- mice. However, C. pneumoniae-infected IFN-alphabetaR-/- or IFN regulatory factor 3-/- mice showed no increased susceptibility and similar IFN-gamma expression compared with wild-type mice. CD4+ or CD8+ cells released IFN-gamma in vivo and conferred protection against C. pneumoniae in a STAT1-independent manner. In contrast, STAT1 mediated a nonredundant protective role of nonhemopoietic cells but not of hemopoietic cells. Nonhemopoietic cells accounted for the expression of STAT1-mediated indoleamine 2, 3-dioxygenase and the p47 GTPase LRG-47, but not inducible NO synthase mRNA. In summary, we demonstrate that STAT1 mediates a cooperative effect of IFN-alphabeta and IFN-gamma on nonhemopoietic cells, resulting in protection against C. pneumoniae.

High Level Expression of Biologically Active Canine Interferon-.ALPHA. Subtype 4 Using a Baculovirus

In this study, a high amount of bioactive recombinant canine interferon-alpha subtype 4 (CaIFN-alpha4) was expressed in a baculovirus system. For easy purification, it was expressed as a CaIFN-alpha4 bearing histidine hexamer at the C-terminal region, designated CaIFN-alpha4His. CaIFN-alpha4His was detected in culture supernatants of insect cells infected with the recombinant virus using sodium dodecyl sulfate-polyarcylamide gel electrophoresis (SDS-PAGE) and Coomassie Brilliant Blue staining. The level of expression was very high, and approximately 1 mg of purified protein, with 5.0 x 10(7) units/mg, was obtained from 300 ml of culture supernatant. The purified product showed antiviral activity against Vesicular stomatitis virus on canine tumor cell line A72 and chicken embryo fibroblast cells.