Abstract:Porcine Epidemic Diarrhea Virus (PEDV) causes severe diarrhea and mortality in piglets. Robust immunity may break the transmission cycle. Expression of antigens in maize grains is a promising method for producing low-cost vaccines. As a first step, we expressed maize constructs containing PEDV S1 spike protein targeted to various cellular locations including the cell wall, endoplasmic reticulum, and vacuole, and fused to carrier proteins E. coli heat labile subunit (LTB) and a dendritic cell (DC) binding pepti… Show more
“…Another study showed that systemic anti-R1 antibody levels were significantly higher in mice orally vaccinated with recombinant R1-LTB protein compared to those vaccinated with R1 alone. In line with these reports, LTB fusion with the C-terminal fragments of botulinum neurotoxins (BoNTs) serotypes C and D [20] , hyopneumoniae antigens [21] , A. pleuropneumoniae toxin epitopes [22] , dengue envelope protein domain III-LTB [4] , porcine epidemic diarrhoea virus spike protein [23] and influenza A virus epitopes (IAVe) [24] , induced broad humoral and cellular immune responses and improved protection against viral challenge in various animal models.…”
The rapid spread of the COVID-19 pandemic, with its devastating medical and economic impacts, triggered an unprecedented race toward development of effective vaccines. The commercialized vaccines are parenterally administered, which poses logistic challenges, while adequate protection at the mucosal sites of virus entry is questionable. Furthermore, essentially all vaccine candidates target the viral spike (S) protein, a surface protein that undergoes significant antigenic drift. This work aimed to develop an oral multi-antigen SARS-CoV-2 vaccine comprised of the receptor binding domain (RBD) of the viral S protein, two domains of the viral nucleocapsid protein (N), and heat-labile enterotoxin B (LTB), a potent mucosal adjuvant. The humoral, mucosal and cell-mediated immune responses of both a three-dose vaccination schedule and a heterologous subcutaneous prime and oral booster regimen were assessed in mice and rats, respectively. Mice receiving the oral vaccine compared to control mice showed significantly enhanced post-dose-3 virus-neutralizing antibody, anti-S IgG and IgA production and N-protein-stimulated IFN-γ and IL-2 secretion by T cells. When administered as a booster to rats following parenteral priming with the viral S1 protein, the oral vaccine elicited markedly higher neutralizing antibody titres than did oral placebo booster. A single oral booster following two subcutaneous priming doses elicited serum IgG and mucosal IgA levels similar to those raised by three subcutaneous doses. In conclusion, the oral LTB-adjuvanted multi-epitope SARS-CoV-2 vaccine triggered versatile humoral, cellular and mucosal immune responses, which are likely to provide protection, while also minimizing technical hurdles presently limiting global vaccination, whether by priming or booster programs.
“…Another study showed that systemic anti-R1 antibody levels were significantly higher in mice orally vaccinated with recombinant R1-LTB protein compared to those vaccinated with R1 alone. In line with these reports, LTB fusion with the C-terminal fragments of botulinum neurotoxins (BoNTs) serotypes C and D [20] , hyopneumoniae antigens [21] , A. pleuropneumoniae toxin epitopes [22] , dengue envelope protein domain III-LTB [4] , porcine epidemic diarrhoea virus spike protein [23] and influenza A virus epitopes (IAVe) [24] , induced broad humoral and cellular immune responses and improved protection against viral challenge in various animal models.…”
The rapid spread of the COVID-19 pandemic, with its devastating medical and economic impacts, triggered an unprecedented race toward development of effective vaccines. The commercialized vaccines are parenterally administered, which poses logistic challenges, while adequate protection at the mucosal sites of virus entry is questionable. Furthermore, essentially all vaccine candidates target the viral spike (S) protein, a surface protein that undergoes significant antigenic drift. This work aimed to develop an oral multi-antigen SARS-CoV-2 vaccine comprised of the receptor binding domain (RBD) of the viral S protein, two domains of the viral nucleocapsid protein (N), and heat-labile enterotoxin B (LTB), a potent mucosal adjuvant. The humoral, mucosal and cell-mediated immune responses of both a three-dose vaccination schedule and a heterologous subcutaneous prime and oral booster regimen were assessed in mice and rats, respectively. Mice receiving the oral vaccine compared to control mice showed significantly enhanced post-dose-3 virus-neutralizing antibody, anti-S IgG and IgA production and N-protein-stimulated IFN-γ and IL-2 secretion by T cells. When administered as a booster to rats following parenteral priming with the viral S1 protein, the oral vaccine elicited markedly higher neutralizing antibody titres than did oral placebo booster. A single oral booster following two subcutaneous priming doses elicited serum IgG and mucosal IgA levels similar to those raised by three subcutaneous doses. In conclusion, the oral LTB-adjuvanted multi-epitope SARS-CoV-2 vaccine triggered versatile humoral, cellular and mucosal immune responses, which are likely to provide protection, while also minimizing technical hurdles presently limiting global vaccination, whether by priming or booster programs.
“…The extensive coverage of the detected peptides of the inserted protein sequence and their presence in all three Enz transgenic developing protein samples with the absence of these peptides in the nontransgenic sample, indicates that the inserted aflatoxin-degrading enzyme is stably produced in developing maize kernels and it has accumulated to appreciable levels to be detected by mass spectroscopy. The subcellular targeting strategy used to express the aflatoxin-degrading enzyme likely enhanced the amount of this enzyme that accumulated in maize developing kernels, as this stabilization strategy has been shown to considerably elevate amounts of inserted proteins in maize kernels (for example [ 47 , 48 ]) and other crop seeds [ 37 , 39 ]. Fig.…”
Background
Aflatoxins are carcinogenic compounds produced by certain species of Aspergillus fungi. The consumption of crops contaminated with this toxin cause serious detrimental health effects, including death, in both livestock and humans. As a consequence, both the detection and quantification of this toxin in food/feed items is tightly regulated with crops exceeding the allowed limits eliminated from food chains. Globally, this toxin causes massive agricultural and economic losses each year.
Results
In this paper we investigate the feasibility of using an aflatoxin-degrading enzyme strategy to reduce/eliminate aflatoxin loads in developing maize kernels. We used an endoplasmic reticulum (ER) targeted sub-cellular compartmentalization stabilizing strategy to accumulate an aflatoxin-degrading enzyme isolated from the edible Honey mushroom Armillariella tabescens and expressed it in embryo tissue in developing maize kernels. Three transgenic maize lines that were determined to be expressing the aflatoxin-degrading enzyme both at the RNA and protein level, were challenged with the aflatoxin-producing strain Aspergillus flavus AF13 and shown to accumulate non-detectable levels of aflatoxin at 14-days post-infection and significantly reduced levels of aflatoxin at 30-days post-infection compared to nontransgenic control Aspergillus-challenged samples.
Conclusions
The expression of an aflatoxin-degrading enzyme in developing maize kernels was shown to be an effective means to control aflatoxin in maize in pre-harvest conditions. This aflatoxin-degradation strategy could play a significant role in the enhancement of both US and global food security and sustainability.
“…Our previous work demonstrated that the S1 antigen could accumulate to high levels in maize and allow for a heat-stable, low-cost production supply of the antigen [33]. In addition, 27-day-old pigs fed maize-produced S1 protein developed high levels of sera neutralization antibodies after being challenged with active PED virus [33]. However, because the disease symptoms are acute only in nursing pigs, protection from the virus could not be evaluated in this study.…”
Section: Introductionmentioning
confidence: 92%
“…Nonetheless, there is only one report expressing the core neutralizing epitope (COE) domain of the PEDV spike protein in maize, which was subsequently purified and injected in mice to elicit antibodies against PEDV [32]. Our previous work demonstrated that the S1 antigen could accumulate to high levels in maize and allow for a heat-stable, low-cost production supply of the antigen [33]. In addition, 27-day-old pigs fed maize-produced S1 protein developed high levels of sera neutralization antibodies after being challenged with active PED virus [33].…”
To investigate whether oral administration of maize-produced S antigen can provide passive immunity to piglets against porcine epidemic diarrhea virus (PEDV), 16 pregnant sows were randomly assigned to one of four treatments: (1) injection of PEDV vaccine (INJ), (2) maize grain without S protein (CON), (3) maize grain containing low dose of S antigen (LOV) and (4) maize grain containing a high dose of S antigen (HOV). Vaccines were administered on days 57, 85 and 110 of gestation. Sows’ serum and colostrum were collected at farrowing and milk on day 6 post-challenge to quantify neutralizing antibodies (NABs) and cytokines. Piglets were challenged with PEDV 3–5 d after farrowing, and severity of disease and mortality assessed on day 11 post-challenge. Disease severity was lower in LOV and INJ compared with HOV and CON, whereas the survival rate increased in piglets from LOV sows compared with HOV and CON (p ≤ 0.001). Higher titers of NABs and lower levels of cytokine granulocyte-macrophage colony-stimulating factor in sows’ milk were positively correlated with piglet survivability (p ≤ 0.05). These data suggest that feeding S protein in corn to pregnant sows protects nursing piglets against PEDV.
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