ABSTRACT. It has been reported that type I interferons (IFN-) 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- subtype 4 (CaIFN-4). We administered purified recombinant CaIFN-4 expressed in a baculovirus system to dogs with or without gingival inflammation. We found that LDOA of CaIFN-4 reduce periodontopathic bactrerial 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-4 has effectiveness for improvement of naturally occurring gingival inflammation in dogs.

We developed a transgenic potato (TrP/R7) expressing the recombinant R7 (rR7) antigen for use as an oral vaccine to protect against a chicken protozoan disease, chicken leucocytozoonosis. The TrP/R7 potato was produced by Agrobacterium tumefaciens-mediated transformation and regeneration, and the R7 gene insertion into potato chromosomes was confirmed by genomic polymerase chain reaction and Southern hybridization. rR7 antigen expression in TrP/R7 potato was also confirmed by sandwich enzyme-linked immunosorbent assay and western blotting using an antibody against the second-generation schizont of Leucocytozoon caulleryi. A transgenic potato clone with the highest rR7 antigen expression (3 mg rR7 antigen per gram of fresh-weight potato leaves) was selected, cultivated, and used in oral administration experiments to examine its ability to boost immunity. Chickens were immunized with chicken leucocytozoonosis vaccine ''Hokken'' by injection, and chickens that developed moderate levels of antibody titres were fed with TrP/R7 leaves. Chickens fed with TrP/R7 leaves showed increased antibody responses. In contrast, chickens fed with non-transgenic potato leaves showed a continuous decrease in antibody titres. Furthermore, chickens fed with TrP/R7 potato leaves showed strong resistance against experimental challenge with L. caulleryi infection. This study demonstrates the use of a plant-based oral vaccine to boost immunity against a protozoan disease.

Antibacterial photodynamic therapy (PDT) has come to attract attention as an alternative therapy for drug-resistant bacteria. Recent reports revealed that antibacterial PDT induces innate immune response and stimulates abundant cytokine secretion as a part of inflammatory responses. However, the underlying mechanism how antibacterial PDT interacts with immune cells responsible for cytokine secretion has not been well outlined. In this study, we aimed to clarify the difference in gene expression and cytokine secretion between combined culture of fibroblasts and macrophages and their independent cultures. SCRC-1008, mouse fibroblast cell line and J774, mouse macrophage-like cell line were co-cultured and PDT treatments with different parameters were carried out. After various incubation periods (1-24 h), cells and culture medium were collected, and mRNA and protein levels for cytokines were measured using real-time PCR and ELISA, respectively. Our results showed that fibroblasts and macrophages interact with each other to mediate the immune response. We propose that fibroblasts initially respond to PDT by expressing Hspa1b, which regulates the NF-κB pathway via Tlr2 and Tlr4. Activation of the NF-κB pathway then results in an enhanced secretion of pro-inflammatory cytokines (TNF-α, IL-6 and IL-1β) and neutrophil chemoattractant MIP-2 and KC from macrophages.

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