Search Results (26)

Using plants as bioreactors, molecular farming has emerged as a versatile and sustainable platform for producing recombinant vaccines, therapeutic proteins, industrial enzymes, and nutraceuticals. This innovative approach leverages the unique advantages of plants, including scalability, cost-effectiveness, and reduced risk of contamination with human pathogens. Recent advancements in gene editing, transient expression systems, and nanoparticle-based delivery technologies have significantly enhanced the efficiency and versatility of plant-based systems. Particularly in vaccine development, molecular farming has demonstrated its potential with notable successes such as Medicago’s Covifenz for COVID-19, illustrating the capacity of plant-based platforms to address global health emergencies rapidly. Furthermore, edible vaccines have opened new avenues in the delivery of vaccines, mainly in settings with low resources where the cold chain used for conventional logistics is a challenge. However, optimization of protein yield and stability, the complexity of purification processes, and regulatory hurdles are some of the challenges that still remain. This review discusses the current status of vaccine development using plant-based expression systems, operational mechanisms for plant expression platforms, major applications in the prevention of infectious diseases, and new developments, such as nanoparticle-mediated delivery and cancer vaccines. The discussion will also touch on ethical considerations, the regulatory framework, and future trends with respect to the transformative capacity of plant-derived vaccines in ensuring greater global accessibility and cost-effectiveness of the vaccination. This field holds great promise for the infectious disease area and, indeed, for applications in personalized medicine and biopharmaceuticals in the near future. Full article

Current mRNA vaccines are mainly administered via intramuscular injection, which induces good systemic immunity but limited mucosal immunity. Achieving mucosal immunity through mRNA vaccination could diminish pathogen replication at the entry site and reduce interhuman transmission. However, delivering mRNA vaccines to mucosae faces challenges like mRNA degradation, poor entry into cells, and reactogenicity. Encapsulating mRNA in extracellular vesicles may protect the mRNA and reduce reactogenicity, making mucosal mRNA vaccines possible. Plant-derived extracellular vesicles from edible fruits have been investigated as mRNA carriers. Studies in animals show that mRNA vehiculated in orange-derived extracellular vesicles can elicit both systemic and mucosal immune responses when administered by the oral, nasal, or intramuscular routes. Once lyophilized, these products show remarkable stability. The optimization of mRNA to improve translation efficiency, immunogenicity, reactogenicity, and stability can be obtained through adjustments of the 5′cap region, poly-A tail, codons selection, and the use of nucleoside analogues. Recent studies have also proposed self-amplifying RNA vaccines containing an RNA polymerase as well as circular mRNA constructs. Data from parenterally primed animals demonstrate the efficacy of nasal immunization with non-adjuvanted protein, and studies in humans indicate that the combination of a parenteral vaccine with the natural exposure of mucosae to the same antigen provides protection and reduces transmission. Hence, mucosal mRNA vaccination would be beneficial at least in organisms pre-treated with parenteral vaccines. This practice could have wide applications for the treatment of infectious diseases. Full article

Nucleic acid delivery through extracellular vesicles (EVs) is a well-preserved evolutionary mechanism in all life kingdoms including eukaryotes, prokaryotes, and plants. EVs naturally allow horizontal transfer of native as well as exogenous functional mRNAs, which once incorporated in EVs are protected from enzymatic degradation. This observation has prompted researchers to investigate whether EVs from different sources, including plants, could be used for vaccine delivery. Several studies using human or bacterial EVs expressing mRNA or recombinant SARS-CoV-2 proteins showed induction of a humoral and cell mediated immune response. Moreover, EV-based vaccines presenting the natural configuration of viral antigens have demonstrated advantages in conferring long-lasting immunization and lower toxicity than synthetic nanoparticles. Edible plant-derived EVs were shown to be an alternative to human EVs for vaccine delivery, especially via oral administration. EVs obtained from orange juice (oEVs) loaded with SARS-CoV-2 mRNAs protected their cargo from enzymatic degradation, were stable at room temperature for one year, and were able to trigger a SARS-CoV-2 immune response in mice. Lyophilized oEVs containing the S1 mRNA administered to rats via gavage induced a specific humoral immune response with generation of blocking antibodies, including IgA and Th1 lymphocyte activation. In conclusion, mRNA-containing oEVs could be used for developing new oral vaccines due to optimal mucosal absorption, resistance to stress conditions, and ability to stimulate a humoral and cellular immune response. Full article

To achieve the World Health Organization’s global Sustainable Development Goals, increased production of high-quality protein for human consumption is required while minimizing, ideally reducing, environmental impacts. One way to achieve these goals is to address losses within current livestock production systems. Infectious diseases are key limiters of edible protein production, affecting both quantity and quality. In addition, some of these diseases are zoonotic threats and potential contributors to the emergence of antimicrobial resistance. Vaccination has proven to be highly successful in controlling and even eliminating several livestock diseases of economic importance. However, many livestock diseases, both existing and emerging, have proven to be recalcitrant targets for conventional vaccination technologies. The threat posed by the COVID-19 pandemic resulted in unprecedented global investment in vaccine technologies to accelerate the development of safe and efficacious vaccines. While several vaccination platforms emerged as front runners to meet this challenge, the clear winner is mRNA-based vaccination. The challenge now is for livestock industries and relevant stakeholders to harness these rapid advances in vaccination to address key diseases affecting livestock production. This review examines the key features of mRNA vaccines, as this technology has the potential to control infectious diseases of importance to livestock production that have proven otherwise difficult to control using conventional approaches. This review focuses on the challenging diseases of ruminants due to their importance in global protein production. Overall, the current literature suggests that, while mRNA vaccines have the potential to address challenges in veterinary medicine, further developments are likely to be required for this promise to be realized for ruminant and other livestock species. Full article

Food insecurity has become a pressing issue on a worldwide scale as the globe plows through a food crisis. The disastrous impact of this menace has been exacerbated by climate change, frequent conflicts, pandemic outbreaks, and the global economic recession, which have been prevalent in recent years. Although food insecurity prevails globally, it is especially critical in some regions in Africa, East and Southeast Asia, and South America. Several efforts have been made to curb food insecurity; however, none have been able to curtail it sufficiently. Genetic engineering of crops is a fast-growing technology that could be a viable tool for mitigating food insecurity. Crop varieties resistant to pests and diseases, abiotic stress, spoilage, or specific herbicides have been developed using this technology. Crops have been modified for increased yield, nutritional content, essential vitamins, and micro-mineral fortification. More intriguing is the advent of plant-derived edible vaccines, which prove equally effective and significantly affordable. However, in many countries, government policies pose a limiting factor for the acceptance of this technology. This article discusses the genetic modification of crops, highlighting its origins, methods, applications, achievements, impact, acceptance, distribution, and potential as a viable antidote to global food insecurity. Full article

mRNA-based vaccines were effective in contrasting SARS-CoV-2 infection. However, they presented several limitations of storage and supply chain, and their parenteral administration elicited a limited mucosal IgA immune response. Extracellular vesicles (EVs) have been recognized as a mechanism of cell-to-cell communication well-preserved in all life kingdoms, including plants. Their membrane confers protection from enzyme degradation to encapsulated nucleic acids favoring their transfer between cells. In the present study, EVs derived from the juice of an edible plant (Citrus sinensis) (oEVs) were investigated as carriers of an orally administered mRNA vaccine coding for the S1 protein subunit of SARS-CoV-2 with gastro-resistant oral capsule formulation. The mRNA loaded into oEVs was protected and was stable at room temperature for one year after lyophilization and encapsulation. Rats immunized via gavage administration developed a humoral immune response with the production of specific IgM, IgG, and IgA, which represent the first mucosal barrier in the adaptive immune response. The vaccination also triggered the generation of blocking antibodies and specific lymphocyte activation. In conclusion, the formulation of lyophilized mRNA-containing oEVs represents an efficient delivery strategy for oral vaccines due to their stability at room temperature, optimal mucosal absorption, and the ability to trigger an immune response. Full article

The 19th century saw the development of vaccines, which were biological preparations designed to enhance immunity against specific diseases. Edible vaccines function by stimulating both systemic and mucosal immune responses against foreign pathogens, and they may potentially protect the host from autoimmunity. The mucosal surfaces provide a convenient and rapid route for delivering therapeutic small molecules. This is due to their large surface areas and easy administration. The effectiveness of mucosal immunization relies on the fact that mucous membranes represent the body’s largest immunogenic organ. Within this interface, there is a well-organized lymphatic structure known as MALT (mucosa-associated lymphoid tissue), which includes both T and B cells and encompasses the adaptive arms of the immune system. Oral vaccines specifically stimulate immune responses in the gut-associated lymphoid tissue (GALT), which consists of lymph nodes, Payer’s patches (where B cells make up about 75% of the population and T cells account for approximately 20%), and isolated lymphoid follicles within the gastrointestinal tract (GIT). However, a significant challenge in developing vaccines is the rapid degradation of antigens within the harsh environment of the digestive tract, which hampers effective protein delivery to the GIT. In light of recent proteomic analysis revealing strong up-regulation of the tryptophan catabolic enzyme indoleamine 2, 3-dioxygenase (IDO1) in DCs inoculated with the Cholera toxin B-subunit-Insulin fusion protein vaccine (CTB-INS), we are interested in investigating the effects of transgene integration into a selected plant cell as an edible vaccine. Full article

Post-weaning diarrhoea and enterotoxaemia caused by Escherichia coli are serious threats in the pig (Sus scrofa domesticus) livestock industry and are responsible for economic losses related to mortality, morbidity and stunted growth. The aim of this study was to evaluate the effect of an engineered tobacco seeds-based edible vaccine in O138 Escherichia coli-challenged piglets throughout a multidisciplinary approach. Thirty-six weaned piglets were enrolled and randomly divided into two experimental groups, a control (C; n = 18) group and a tobacco edible vaccination group (T, n = 18), for 29 days of trial. At days 0, 1, 2, 5 and 14, piglets of the T group were fed with 10 g of the engineered tobacco seeds line expressing F18 and VT2eB antigens, while the C group received wild-type tobacco seeds. After 20 days, 6 piglets/group were orally challenged with the Escherichia coli O138 strain (creating four subgroups: UC = unchallenged control, CC = challenged control, UT = unchallenged tobacco, CT = challenged tobacco) and fed with a high protein diet for 3 consecutive days. Zootechnical, clinical, microbiological, histological and immunological parameters were assayed and registered during the 9 days of post-challenge follow up. At 29 days post-challenge, the CT group displayed a lower average of the sum of clinical scores compared to the CC group (p < 0.05), while the CC group showed a higher average sum of the faecal score (diarrhoea) (p < 0.05) than the CT group. A decreased number of days of shedding of the pathogenic strain was observed in the CT compared to the CC group (p < 0.05). Specific anti-F18 IgA molecules were significantly higher in the CT group compared to the CC group’s faecal samples during the post-challenge period (p < 0.01). In conclusion, edible vaccination with engineered tobacco seeds showed a protective effect on clinical symptoms and diarrhoea incidence during the post-challenge period, characterized by a limited time of pathogenic strain shedding in faeces. Full article

Poliovirus (PV) is the causative agent of poliomyelitis and is a target of the global eradication programs of the World Health Organization (WHO). After eradication of type 2 and 3 wild-type PVs, vaccine-derived PV remains a substantial threat against the eradication as well as type 1 wild-type PV. Antivirals could serve as an effective means to suppress the outbreak; however, no anti-PV drugs have been approved at present. Here, we screened for effective anti-PV compounds in a library of edible plant extracts (a total of 6032 extracts). We found anti-PV activity in the extracts of seven different plant species. We isolated chrysophanol and vanicoside B (VCB) as the identities of the anti-PV activities of the extracts of Rheum rhaponticum and Fallopia sachalinensis, respectively. VCB targeted the host PI4KB/OSBP pathway for its anti-PV activity (EC₅₀ = 9.2 μM) with an inhibitory effect on in vitro PI4KB activity (IC₅₀ = 5.0 μM). This work offers new insights into the anti-PV activity in edible plants that may serve as potent antivirals for PV infection. Full article

Background: The house cricket, Acheta domesticus, is one of the most farmed insects worldwide and the foundation of an emerging industry using insects as a sustainable food source. Edible insects present a promising alternative for protein production amid a plethora of reports on climate change and biodiversity loss largely driven by agriculture. As with other crops, genetic resources are needed to improve crickets for food and other applications. Methods: We present the first high quality annotated genome assembly of A. domesticus from long read data and scaffolded to chromosome level, providing information needed for genetic manipulation. Results: Gene groups related to immunity were annotated and will be useful for improving value to insect farmers. Metagenome scaffolds in the A. domesticus assembly, including Invertebrate Iridescent Virus 6 (IIV6), were submitted as host-associated sequences. We demonstrate both CRISPR/Cas9-mediated knock-in and knock-out of A. domesticus and discuss implications for the food, pharmaceutical, and other industries. RNAi was demonstrated to disrupt the function of the vermilion eye-color gene producing a useful white-eye biomarker phenotype. Conclusions: We are utilizing these data to develop technologies for downstream commercial applications, including more nutritious and disease-resistant crickets, as well as lines producing valuable bioproducts, such as vaccines and antibiotics. Full article

Severe acute respiratory syndrome–Coronavirus 2 (SARS-CoV-2) can infect various human organs, including the respiratory, circulatory, nervous, and gastrointestinal ones. The virus is internalized into human cells by binding to the human angiotensin-converting enzyme 2 (ACE2) receptor through its spike protein (S-glycoprotein). As S-glycoprotein is required for the attachment and entry into the human target cells, it is the primary mediator of SARS-CoV-2 infectivity. Currently, this glycoprotein has received considerable attention as a key component for the development of antiviral vaccines or biologics against SARS-CoV-2. Moreover, since the ACE2 receptor constitutes the main entry route for the SARS-CoV-2 virus, its soluble form could be considered as a promising approach for the treatment of coronavirus disease 2019 infection (COVID-19). Both S-glycoprotein and ACE2 are highly glycosylated molecules containing 22 and 7 consensus N-glycosylation sites, respectively. The N-glycan structures attached to these specific sites are required for the folding, conformation, recycling, and biological activity of both glycoproteins. Thus far, recombinant S-glycoprotein and ACE2 have been produced primarily in mammalian cells, which is an expensive process. Therefore, benefiting from a cheaper cell-based biofactory would be a good value added to the development of cost-effective recombinant vaccines and biopharmaceuticals directed against COVID-19. To this end, efficient protein synthesis machinery and the ability to properly impose post-translational modifications make microalgae an eco-friendly platform for the production of pharmaceutical glycoproteins. Notably, several microalgae (e.g., Chlamydomonas reinhardtii, Dunaliella bardawil, and Chlorella species) are already approved by the U.S. Food and Drug Administration (FDA) as safe human food. Because microalgal cells contain a rigid cell wall that could act as a natural encapsulation to protect the recombinant proteins from the aggressive environment of the stomach, this feature could be used for the rapid production and edible targeted delivery of S-glycoprotein and soluble ACE2 for the treatment/inhibition of SARS-CoV-2. Herein, we have reviewed the pathogenesis mechanism of SARS-CoV-2 and then highlighted the potential of microalgae for the treatment/inhibition of COVID-19 infection. Full article

Despite the current advances in global vaccination against SARS-CoV-2, boosting is still required to sustain immunity in the population, and the induction of sterilizing immunity remains as a pending goal. Low-cost oral immunogens could be used as the basis for the design of affordable and easy-to-administer booster vaccines. Algae stand as promising platforms to produce immunogens at low cost, and it is possible to use them as oral delivery carriers since they are edible (not requiring complex purification and formulation processes). Herein, a Chlamydomonas-made SARS-CoV-2 RBD was evaluated as an oral immunogen in mice to explore the feasibility of developing an oral algae-based vaccine. The test immunogen was stable in freeze-dried algae biomass and able to induce, by the oral route, systemic and mucosal humoral responses against the spike protein at a similar magnitude to those induced by injected antigen plus alum adjuvant. IgG subclass analysis revealed a Th2-bias response which lasted over 4 months after the last immunization. The induced antibodies showed a similar reactivity against either Delta or Omicron variants. This study represents a step forward in the development of oral vaccines that could accelerate massive immunization. Full article

Flaviviruses are a threat to public health and can cause major disease outbreaks. Tick-borne encephalitis (TBE) is caused by a flavivirus, and it is one of the most important causes of viral encephalitis in Europe and is on the rise in Sweden. As there is no antiviral treatment available, vaccination remains the best protective measure against TBE. Currently available TBE vaccines are based on formalin-inactivated virus produced in cell culture. These vaccines must be delivered by intramuscular injection, have a burdensome immunization schedule, and may exhibit vaccine failure in certain populations. This project aimed to develop an edible TBE vaccine to trigger a stronger immune response through oral delivery of viral antigens to mucosal surfaces. We demonstrated successful expression and post-translational processing of flavivirus structural proteins which then self-assembled to form virus-like particles in Nicotiana benthamiana. We performed oral toxicity tests in mice using various plant species as potential bioreactors and evaluated the immunogenicity of the resulting edible vaccine candidate. Mice immunized with the edible vaccine candidate did not survive challenge with TBE virus. Interestingly, immunization of female mice with a commercial TBE vaccine can protect their offspring against TBE virus infection. Full article

Tremendous advances in crop biotechnology related to the availability of molecular tools and methods developed for transformation and regeneration of specific plant species have been observed. As a consequence, the interest in plant molecular farming aimed at producing the desired therapeutic proteins has significantly increased. Since the middle of the 1980s, recombinant pharmaceuticals have transformed the treatment of many serious diseases and nowadays are used in all branches of medicine. The available systems of the synthesis include wild-type or modified mammalian cells, plants or plant cell cultures, insects, yeast, fungi, or bacteria. Undeniable benefits such as well-characterised breeding conditions, safety, and relatively low costs of production make plants an attractive yet competitive platform for biopharmaceutical production. Some of the vegetable plants that have edible tubers, fruits, leaves, or seeds may be desirable as inexpensive bioreactors because these organs can provide edible vaccines and thus omit the purification step of the final product. Some crucial facts in the development of plant-made pharmaceuticals are presented here in brief. Although crop systems do not require more strictly dedicated optimization of methodologies at any stages of the of biopharmaceutical production process, here we recall the complete framework of such a project, along with theoretical background. Thus, a brief review of the advantages and disadvantages of different systems, the principles for the selection of cis elements for the expression cassettes, and available methods of plant transformation, through to the protein recovery and purification stage, are all presented here. We also outline the achievements in the production of biopharmaceuticals in economically important crop plants and provide examples of their clinical trials and commercialization. Full article

We investigated the prophylactic and therapeutic effects of the oral administration of transgenic rice seeds expressing a hypoallergenic Bet v 1 derivative of allergic birch pollen conjunctivitis in mice. Transgenic rice seed depositing a chimeric molecule called TPC7 (tree pollen chimera 7) created by DNA shuffling of Bet v 1 family sequences from birch, alder and hazel in protein bodies of endosperm was generated. BALB/c mice were sensitized to birch pollen in alum and challenged with pollen in eyedrops. They were fed TPC7 transgenic or non-transgenic (control) rice seeds for 14 d before sensitization (prophylactic protocol) or 17 d after sensitization (therapeutic protocol). The clinical score and number of conjunctival eosinophils were significantly lower in TPC7-fed mice than in the control mice based on both the prophylactic and therapeutic protocols. Serum concentration of allergen-specific IgE did not differ between TPC7-fed and control groups in either protocol. Prophylactic administration of TPC7 downregulated the production of IL-4 and IFN-γ, whereas therapeutic administration of TPC7 upregulated the production of IFN-γ by allergen-stimulated splenocytes. Prophylactic or therapeutic oral administration of transgenic rice expressing TPC7 suppressed birch pollen-induced allergic conjunctivitis in mice. Feeding transgenic rice is a potentially effective approach as an allergen-specific immunotherapy for allergic conjunctivitis. Full article