Transplastomic plants yield a multicomponent vaccine against cysticercosis

Regulation of piglet T-cell immune responses by thioredoxin peroxidase from Cysticercus cellulosae excretory-secretory antigens

Taenia solium (T. solium) cysticercosis is a serious threat to human health and animal husbandry. During parasitization, Cysticercus cellulosae (C. cellulosae) can excrete and secrete antigens that modulate the host's T-cell immune responses. However, the composition of C. cellulosae excretory-secretory antigens (ESAs) is complex. This study sought to identify the key molecules in C. cellulosae ESAs involved in regulating T-cell immune responses. Thus, we screened for thioredoxin peroxidase (TPx), with the highest differential expression, as the key target by label-free quantification proteomics of C. cellulosae and its ESAs. In addition, we verified whether TPx protein mainly exists in C. cellulosae ESAs. The TPx recombinant protein was prepared by eukaryotic expression, and ESAs were used as the experimental group to further investigate the effect of TPx protein on the immune response of piglet T cells in vitro. TPx protein induced an increase in CD4+ T cells in piglet peripheral blood mononuclear cells (PBMCs), while CD8+ T cells did not change significantly. This resulted in an imbalance in the CD4+/CD8+ T-cell ratio and an increase in CD4+CD25+Foxp3+ Treg cells in the PBMCs. In addition, TPx protein initiated T helper 2 (Th2)-type immune responses by secreting IL-4 and IL-10 and suppressed Th1/Th17-type immune responses. The results showed that ESAs were involved in regulating piglet T-cell immune responses cells. This suggests that TPx protein found in ESAs plays an essential role to help the parasite evade host immune attack. Moreover, this lays a foundation for the subsequent exploration of the mechanism through which TPx protein regulates signaling molecules to influence T-cell differentiation.

Plastidial Expression of 3β-Hydroxysteroid Dehydrogenase and Progesterone 5β-Reductase Genes Confer Enhanced Salt Tolerance in Tobacco

The short-chain dehydrogenase/reductase (SDR) gene family is widely distributed in all kingdoms of life. The SDR genes, 3β-hydroxysteroid dehydrogenase (3β-HSD) and progesterone 5-β-reductases (P5βR1, P5βR2) play a crucial role in cardenolide biosynthesis pathway in the Digitalis species. However, their role in plant stress, especially in salinity stress management, remains unexplored. In the present study, transplastomic tobacco plants were developed by inserting the 3β-HSD, P5βR1 and P5βR2 genes. The integration of transgenes in plastomes, copy number and transgene expression at transcript and protein level in transplastomic plants were confirmed by PCR, end-to-end PCR, qRT-PCR and Western blot analysis, respectively. Subcellular localization analysis showed that 3β-HSD and P5βR1 are cytoplasmic, and P5βR2 is tonoplast-localized. Transplastomic lines showed enhanced growth in terms of biomass and chlorophyll content compared to wild type (WT) under 300 mM salt stress. Under salt stress, transplastomic lines remained greener without negative impact on shoot or root growth compared to the WT. The salt-tolerant transplastomic lines exhibited enhanced levels of a series of metabolites (sucrose, glutamate, glutamine and proline) under control and NaCl stress. Furthermore, a lower Na+/K+ ratio in transplastomic lines was also observed. The salt tolerance, mediated by plastidial expression of the 3β-HSD, P5βR1 and P5βR2 genes, could be due to the involvement in the upregulation of nitrogen assimilation, osmolytes as well as lower Na+/K+ ratio. Taken together, the plastid-based expression of the SDR genes leading to enhanced salt tolerance, which opens a window for developing saline-tolerant plants via plastid genetic engineering.

Plant-made vaccines against parasites: bioinspired perspectives to fight against Chagas disease

Introduction: Three decades of evidence have demonstrated that plants are an affordable platform for biopharmaceutical production and delivery. For instance, several plant-made recombinant proteins have been approved for commercialization under good manufacturing practice (GMP). Thus far, plant-based vaccine prototypes have been evaluated at pre- and clinical levels. Particularly, plant-made vaccines against parasitic diseases, such as malaria, cysticercosis, and toxoplasmosis have been successfully produced and orally delivered with promising outcomes in terms of immunogenicity and protection. The experience on several approaches and technical strategies over 30 years accounts for their potential low-cost, high scalability, and easy administration.Areas covered: This platform is an open technology to fight against Chagas disease, one of the most important neglected tropical diseases worldwide.Expert opinion: This review provides a perspective for the potential use of plants as a production platform and delivery system of Trypanosoma cruzi recombinant antigens, analyzing the advantages and limitations with respect to plant-made vaccines produced for other parasitic diseases. Plant-made vaccines are envisioned to fight against Chagas disease and other neglected tropical diseases in those countries suffering endemic prevalence.

Use of Veterinary Vaccines for Livestock as a Strategy to Control Foodborne Parasitic Diseases

Foodborne diseases (FBDs) are a major concern worldwide since they are associated with high mortality and morbidity in the human population. Among the causative agents of FBDs, Taenia solium, Echinococcus granulosus, Toxoplasma gondii, Cryptosporidium spp., and Trichinella spiralis are listed in the top global risk ranking of foodborne parasites. One common feature between them is that they affect domestic livestock, encompassing an enormous risk to global food production and human health from farm to fork, infecting animals, and people either directly or indirectly. Several approaches have been employed to control FBDs caused by parasites, including veterinary vaccines for livestock. Veterinary vaccines against foodborne parasites not only improve the animal health by controlling animal infections but also contribute to increase public health by controlling an important source of FBDs. In the present review, we discuss the advances in the development of veterinary vaccines for domestic livestock as a strategy to control foodborne parasitic diseases.

The role of plant expression platforms in biopharmaceutical development: possibilities for the future

Introduction: Plant-made vaccines have been in the pipeline for nearly thirty years. Generated stably in transgenic plants or transiently using virus expression systems, pharmaceuticals have been developed to address global pandemics as well as several emerging One Health Diseases.Areas covered: This review describes the generation of plant-made vaccines to address some of the world's most growing health concerns, including both infectious and non-communicable diseases, such as cancer. The review provides an overview of the research taking place in this field over the past three to five years. The PubMed database was searched under the topic of plant-made vaccine between the periods of 2014 and 2019.Expert opinion: While vaccines and other biologics have been shown to be cheap safe and efficacious, they have not yet entered the marketplace largely due to regulatory constraints. The lack of an appropriate regulatory structure to guide plant-made vaccines through to commercial development has stalled efforts to provide life-saving medicines to low- and middle-income families. In my opinion, it is paramount that regulatory hurdles are mitigated to address emerging infectious diseases such as Ebola and Zika in a timely manner.