Oral immunotherapy for pollen allergy using T-cell epitope-containing egg white derived from genetically manipulated chickens

The science of genetically modified poultry

The exuberant development of targeted genome editing has revolutionized research on the chicken genome, generating chickens with beneficial parameters. The chicken model is a crucial experimental tool that can be utilized for drug manufacture, preclinical research, pathological observation, and other applications. In essence, tweaking the chicken’s genome has enabled the poultry industry to get more done with less, generating genetically modified chickens that lay eggs containing large amounts of lifesaving humanized drugs. The transition of gene editing from concept to practical application has been dramatically hastened by the development of programmable nucleases, bringing scientists closer than ever to the efficient producers of tomorrow’s medicines. Combining the developmental and physiological characteristics of the chicken with cutting-edge genome editing, the chicken furnishes a potent frontier that is foreseen to be actively pursued in the future. Herein we review the current and future prospects of gene editing in chickens and the contributions to the development of humanized pharmaceuticals.

Calcium carbonate supplementation to chorioallantoic membranes improves hatchability in shell-less chick embryo culture

Developing chick embryos are a classical research tool in developmental biology. The whole embryo culture technique can be applied to various fields, such as embryo manipulation, toxicology, tumorigenesis, and basic research in regenerative medicine. When used for the generation of transgenic chickens, a high hatchability of genetically engineered embryos is essential to support normal embryonic development during culture. In this study, calcium carbonate, which is the main component of eggshells, was added as a calcium source in shell-less chick embryo cultures using a transparent plastic film as a culture vessel. In the absence of a calcium source in the shell-less culture system, embryogenesis ceased during culture, resulting in failed embryonic hatching. We found that the direct addition of calcium carbonate to the chorioallantoic membrane of the developing embryo was effective for the hatching of cultured chick embryos. The amount, timing, and location of calcium carbonate addition were investigated to maximize the hatchability of cultured embryos. Starting from the time of calcium carbonate supplementation, >40% hatchability was obtained with the optimal condition. This established method of shell-less chick embryo culture provides a useful tool in basic and applied fields of chick embryo manipulation.

Solid-in-Oil Nanodispersions for Transcutaneous Immunotherapy of Japanese Cedar Pollinosis

Japanese cedar pollinosis (JCP) is a common affliction caused by an allergic reaction to cedar pollen and is considered a disease of national importance in Japan. Antigen-specific immunotherapy (AIT) is the only available curative treatment for JCP. However, low compliance and persistence have been reported among patients subcutaneously or sublingually administered AIT comprising a conventional antigen derived from a pollen extract. To address these issues, many research studies have focused on developing a safer, simpler, and more effective AIT for JCP. Here, we review the novel antigens that have been developed for JCP AIT, discuss their different administration routes, and present the effects of anti-allergy treatment. Then, we describe a new form of AIT called transcutaneous immunotherapy (TCIT) and its solid-in-oil (S/O) nanodispersion formulation, which is a promising antigen delivery system. Finally, we discuss the applications of S/O nanodispersions for JCP TCIT. In this context, we predict that TCIT delivery by using a S/O nanodispersion loaded with novel antigens may offer an easier, safer, and more effective treatment option for JCP patients.

Targeted knock-in into the OVA locus of chicken cells using CRISPR/Cas9 system with homology-independent targeted integration

It is anticipated that transgenic avian species will be used as living bioreactors for the production of biopharmaceutical proteins. Precise tissue-specific expression of exogenous genes is a major challenge for the development of avian bioreactors. No robust vector is currently available for highly efficient and specific expression. In recent years, genome-editing techniques such as the CRISPR/Cas9 system have emerged as efficient and user-friendly genetic modification tools. Here, to apply the CRISPR/Cas9 system for the development of transgenic chickens, guide RNA sequences (gRNAs) of the CRISPR/Cas9 system for the ovalbumin (OVA) locus were evaluated for the oviduct-specific expression of exogenous genes. An EGFP gene expression cassette was introduced into the OVA locus of chicken DF-1 and embryonic fibroblasts using the CRISPR/Cas9 system mediated by homology-independent targeted integration. For the knock-in cells, EGFP expression was successfully induced by activation of the endogenous OVA promoter using the dCas9-VPR transactivation system. The combination of gRNAs designed around the OVA TATA box was important to induce endogenous OVA gene expression with high efficiency. These methods provide a useful tool for studies on the creation of transgenic chicken bioreactors and the activation of tissue-specific promoters.

Next generation immunotherapy for tree pollen allergies

Tree pollen induced allergies are one of the major medical and public health burdens in the industrialized world. Allergen-Specific Immunotherapy (AIT) through subcutaneous injection or sublingual delivery is the only approved therapy with curative potential to pollen induced allergies. AIT often is associated with severe side effects and requires long-term treatment. Safer, more effective and convenient allergen specific immunotherapies remain an unmet need. In this review article, we discuss the current progress in applying protein and peptide-based approaches and DNA vaccines to the clinical challenges posed by tree pollen allergies through the lens of preclinical animal models and clinical trials, with an emphasis on the birch and Japanese red cedar pollen induced allergies.

Gene editing in birds takes flight

The application of gene editing (GE) technology to create precise changes to the genome of bird species will provide new and exciting opportunities for the biomedical, agricultural and biotechnology industries, as well as providing new approaches for producing research models. Recent advances in modifying both the somatic and germ cell lineages in chicken indicate that this species, and conceivably soon other avian species, has joined a growing number of model organisms in the gene editing revolution.

Transcutaneous pollinosis immunotherapy using a solid-in-oil nanodispersion system carrying T cell epitope peptide and R848

Antigen‐specific immunotherapy is the only curative approach for the treatment of allergic diseases such as Japanese cedar pollinosis. Immunotherapy using a T cell epitope vaccine in combination with the adjuvant R848 is of particular interest as a safe and effective approach to treat allergic diseases. Herein, we propose a simple and easy to handle vaccine administration method using the original solid‐in‐oil (S/O) nanodispersion system that permeates through the skin. The S/O nanodispersion system is composed of nanoparticles of hydrophilic molecules surrounded with hydrophobic surfactants that are dispersed in an oil vehicle. The system has potential to carry and deliver both hydrophilic and hydrophobic bioactives. Hydrophilic T cell epitope peptide was efficiently delivered through mouse skin using the S/O nanodispersion system and lowered antigen‐specific IgE levels in pollinosis model mice. Addition of the hydrophobic adju1vant R848 significantly lowered the antibody secretion and shifted the Th1/Th2‐balance toward Th1‐type immunity in the model mice, showing the potential to alleviate Japanese cedar pollinosis.

Solid-in-oil nanodispersions for transdermal drug delivery systems

Transdermal administration of drugs has advantages over conventional oral administration or administration using injection equipment. The route of administration reduces the opportunity for drug evacuation before systemic circulation, and enables long-lasting drug administration at a modest body concentration. In addition, the skin is an attractive route for vaccination, because there are many immune cells in the skin. Recently, solid-in-oil nanodisperison (S/O) technique has demonstrated to deliver cosmetic and pharmaceutical bioactives efficiently through the skin. S/O nanodispersions are nanosized drug carriers designed to overcome the skin barrier. This review discusses the rationale for preparation of efficient and stable S/O nanodispersions, as well as application examples in cosmetic and pharmaceutical materials including vaccines. Drug administration using a patch is user-friendly, and may improve patient compliance. The technique is a potent transcutaneous immunization method without needles.

Transcutaneous Peptide Immunotherapy of Japanese Cedar Pollinosis Using Solid-in-Oil Nanodispersion Technology

Peptide immunotherapy is an attractive approach to relieve allergic symptoms such as rhinitis and asthma. Treatment of Japanese cedar pollinosis (Cryptomeria japonica; Cj), from which over one quarter of Japanese population suffer, is becoming a great concern. Recently, oral feeding of a peptide (7crp) consisting of seven immunodominant human T cell epitopes derived from two enzymes present in Cj pollen was demonstrated to have a benefit in treating Cj pollinosis. In this work, we aimed to apply a novel transcutaneous administration system as a simple and easy peptide delivery for an immunotherapy using a T cell epitope peptide. A modified 7crp peptide (7crpR) which contained triarginine linkers between each epitopes was designed to increase water solubility and was encapsulated in a unique solid-in-oil (S/O) nanodispersion. The S/O nanodispersion consists of a nano-sized peptide-surfactant complex dispersed in an oil vehicle. The S/O nanopartilces having an average diameter of 230 nm facilitated the permeation of the peptide 7crpR into the skin and suppressed serum total IgE and antigen-specific IgE levels in a Cj pollinosis mouse model. Transcutaneous administration of the T cell epitope peptide using the S/O nanodispersion system has potential for future simple and easy immunotherapy of Cj pollinosis.

Analysis of T-cell epitopes of Der f3 in Dermatophagoides farina

House dust mites (HDM) are most important indoor allergens for humans. Der f3, one of the potent allergens with allergenicity, is derived from Dermatophagoides farina (D. farinae), and exhibits strong allergenicity that was confirmed in our previous work. The current study was undertaken to determine the localization of T-cell epitope of Der f3. We initially developed the T-cell fraction from BALB/c mice sensitized with recombinant Der f3 to determine the T-cell epitopes in the murine models, and performed T cell proliferation assay with 25 synthetic overlapping peptides of Der f3. The results indicated that T-cell reactive region of murine were assigned on amino acid range 41-60, 101-120, 161-180 and 201-220, respectively. In addition, we did T-cell proliferation experiment, respectively using the 4 murine T-cell epitope peptide and the human T-cell lines from three patients allergic to mite allergens in order to verify homogenous T-cell epitopes in humans. The results indicated that the amino acid sequences of 41-60, 101-120 and 161-180 had induced T cell proliferation in humans, yet 201-220 failed to. These findings suggest that T-cell epitope in Der f3 is located in the amino acid sequences of 41-60, 101-120 and 161-180, respectively. T-cell epitope localization detected in our study may provide a basis for development of animal therapeutic model and peptide vaccine for asthma.