In the last few years, plants have become an increasingly attractive platform for recombinant protein production. This builds on two decades of research, starting with transgenic approaches to ...develop oral vaccines in which antigens or therapeutics can be delivered in processed plant biomass, and progressing to transient expression approaches whereby high yields of purified targets are administered parenterally. The advantages of plant-based expression systems include high scalability, low upstream costs, biocontainment, lack of human or animal pathogens, and ability to produce target proteins with desired structures and biological functions. Using transgenic and transient expression in whole plants or plant cell culture, a variety of recombinant subunit vaccine candidates, therapeutic proteins, including monoclonal antibodies, and dietary proteins have been produced. Some of these products have been tested in early phase clinical trials, and show safety and efficacy. Among those are mucosal vaccines for diarrheal diseases, hepatitis B and rabies; injectable vaccines for non-Hodgkin's lymphoma, H1N1 and H5N1 strains of influenza A virus, and Newcastle disease in poultry; and topical antibodies for the treatment of dental caries and HIV. As lead plant-based products have entered clinical trials, there has been increased emphasis on manufacturing under current Good Manufacturing Practice (cGMP) guidelines, and the preparation and presentation to the relevant government agencies of regulatory packages.
To exploit highly conserved and difficult drug targets, including multipass membrane proteins, monoclonal antibody discovery efforts increasingly rely on the advantages offered by divergent species ...such as rabbits, camelids, and chickens. Here, we provide an overview of antibody discovery technologies, analyze gaps in therapeutic antibodies that stem from the historic use of mice, and examine opportunities to exploit previously inaccessible targets through discovery now possible in alternate species. We summarize the clinical development of antibodies raised from divergent species, discussing how these animals enable robust immune responses against highly conserved binding sites and yield antibodies capable of penetrating functional pockets via long HCDR3 regions. We also discuss the value of pan-reactive molecules often produced by these hosts, and how these antibodies can be tested in accessible animal models, offering a faster path to clinical development.
Plants have a demonstrated potential for large-scale, rapid production of recombinant proteins for diverse product applications, including subunit vaccines and monoclonal antibodies. In this field, ...the accent has recently shifted from the engineering of "edible" vaccines based on stable expression of target protein in transgenic or transplastomic plants to the development of purified formulated vaccines that are delivered via injection. The injectable vaccines are commonly produced using transient expression of target gene delivered into genetically unmodified plant host via viral or bacterial vectors. Most viral vectors are based on plant RNA viruses, where nonessential sequences are replaced with the gene of interest. Utilization of viral hybrids that consist of genes and regulatory elements of different virus species, or transcomplementation systems (vector/transgene) had a substantial impact on the level of target protein expression. Development and introduction of agroviral hybrid vectors that combine genetic elements of bacterial binary plasmids and plant viral vectors, and agroinfiltration as a tool of the vector delivery have resulted in significant progress in large-scale production of recombinant vaccines and monoclonal antibodies in plants. This article presents an overview of plant hybrid viral vector expression systems developed so far.
Highlights ► Virus-like particles (VLPs) are a class of recombinant subunit vaccines. ► VLPs resemble native viruses but lack infectious genetic material. ► VLPs are promising vaccines due to strong ...immunogenicity and safety. ► VLPs can be produced in prokaryotic or eukaryotic expression systems, or in vitro . ► VLP-based vaccine candidates targeting many diseases are in clinical development.
In 2009, a novel H1N1 swine influenza virus was isolated from infected humans in Mexico and the United States, and rapidly spread around the world. Another virus, a highly pathogenic avian influenza ...virus of the H5N1 subtype, identified by the World Health Organization as a potential pandemic threat in 1997, continues to be a significant risk. While vaccination is the preferred strategy for the prevention and control of influenza infections, the traditional egg-based approach to producing influenza vaccines does not provide sufficient capacity and adequate speed to satisfy global needs to combat newly emerging strains, seasonal or potentially pandemic. Significant efforts are underway to develop and implement new cell substrates with improved efficiency for influenza vaccine development and manufacturing. In recent years, plants have been used to produce recombinant proteins including subunit vaccines and antibodies. The main advantages of using plant systems for the production of vaccine antigens against influenza are their independence from pathogenic viruses, and cost and time efficiency. Here, we describe the large-scale production of recombinant hemagglutinin proteins from A/California/04/09 (H1N1) and A/Indonesia/05/05 (H5N1) strains of influenza virus in Nicotiana benthamiana plants, and their immunogenicity (serum hemagglutination inhibition and virus neutralizing antibodies), and safety in animal models. These results support the testing of these candidate vaccines in human volunteers and also the utility of our plant expression system for large-scale recombinant influenza vaccine production.
Antibody Production in Plants and Green Algae Yusibov, Vidadi; Kushnir, Natasha; Streatfield, Stephen J
Annual review of plant biology,
04/2016, Letnik:
67, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Monoclonal antibodies (mAbs) have a wide range of modern applications, including research, diagnostic, therapeutic, and industrial uses. Market demand for mAbs is high and continues to grow. Although ...mammalian systems, which currently dominate the biomanufacturing industry, produce effective and safe recombinant mAbs, they have a limited manufacturing capacity and high costs. Bacteria, yeast, and insect cell systems are highly scalable and cost effective but vary in their ability to produce appropriate posttranslationally modified mAbs. Plants and green algae are emerging as promising production platforms because of their time and cost efficiencies, scalability, lack of mammalian pathogens, and eukaryotic posttranslational protein modification machinery. So far, plant- and algae-derived mAbs have been produced predominantly as candidate therapeutics for infectious diseases and cancer. These candidates have been extensively evaluated in animal models, and some have shown efficacy in clinical trials. Here, we review ongoing efforts to advance the production of mAbs in plants and algae.
Dendritic cells (DC) are usually thought of as antigen‐presenting cells for T cells. However, recent studies from our laboratory and those of others have shown that they have important roles in ...B‐cell activation and regulation of antibody synthesis. Rat DC make short term interactions with resting B cells and these interactions can be stimulated by cross‐linking molecules on either cell surface. These DC can retain antigen in native form for at least 36 h in vivo and in vitro and can subsequently release it for recognition by B cells. In vivo antibody responses induced by antigen‐pulsed DC are skewed towards IgG. In vitro, naive B cells incubated with antigen‐pulsed DC subsequently secrete IgM and IgG when cultured with an antigen‐specific CD4+ T‐cell line, whereas if B cells are incubated with antigen without DC, only IgM is produced. These observations show that DC play an important role in the initiation of and regulation of antibody synthesis.
Summary
Despite progress in the prevention and treatment of infectious diseases, they continue to present a major threat to public health. The frequency of emerging and reemerging infections and the ...risk of bioterrorism warrant significant efforts towards the development of prophylactic and therapeutic countermeasures. Vaccines are the mainstay of infectious disease prophylaxis. Traditional vaccines, however, are failing to satisfy the global demand because of limited scalability of production systems, long production timelines and product safety concerns. Subunit vaccines are a highly promising alternative to traditional vaccines. Subunit vaccines, as well as monoclonal antibodies and other therapeutic proteins, can be produced in heterologous expression systems based on bacteria, yeast, insect cells or mammalian cells, in shorter times and at higher quantities, and are efficacious and safe. However, current recombinant systems have certain limitations associated with production capacity and cost. Plants are emerging as a promising platform for recombinant protein production due to time and cost efficiency, scalability, lack of harboured mammalian pathogens and possession of the machinery for eukaryotic post‐translational protein modification. So far, a variety of subunit vaccines, monoclonal antibodies and therapeutic proteins (antivirals) have been produced in plants as candidate countermeasures against emerging, reemerging and bioterrorism‐related infections. Many of these have been extensively evaluated in animal models and some have shown safety and immunogenicity in clinical trials. Here, we overview ongoing efforts to producing such plant‐based countermeasures.
Influenza infections continue to present a major threat to public health. Traditional modes of influenza vaccine manufacturing are failing to satisfy the global demand because of limited scalability ...and long production timelines. In contrast, subunit vaccines (SUVs) can be produced in heterologous expression systems in shorter times and at higher quantities. Plants are emerging as a promising platform for SUV production due to time efficiency, scalability, lack of harbored mammalian pathogens and possession of the machinery for eukaryotic post-translational protein modifications. So far, several organizations have utilized plant-based transient expression systems to produce SUVs against influenza, including vaccines based on virus-like particles. Plant-produced influenza SUV candidates have been extensively evaluated in animal models and some have shown safety and immunogenicity in clinical trials. Here, the authors review ongoing efforts and challenges to producing influenza SUV candidates in plants and discuss the likelihood of bringing these products to the market.
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