Effect of Molecular Dynamics and Internal Water Contact on the Photophysical Properties of Red pH-Sensitive Proteins

The pH dependence of the absorption and (time-resolved) fluorescence of two red-shifted fluorescent proteins, mCardinal and mNeptune, was investigated. Decay-associated spectra were measured following fluorescence excitation at 470 nm in PBS buffer with a pH that ranged from 5.5 to 8.0. The fluorescence of both proteins shows two different decay components. mCardinal exhibits an increase in the long-lived fluorescence component with acidification from 1.34 ns at pH 8.0 to 1.62 ns at pH 5.5. An additional fast decay component with 0.64 ns at pH 8.0 up to 1.1 ns at pH 5.5 was found to be blue-shifted compared to the long-lived component. The fluorescence lifetime of mNeptune is insensitive to pH. DAS of mCardinal were simulated assuming a coupled two-level system to describe the 1S state of the chromophore within two different conformations of the protein. MD simulations were conducted to correlate the experimentally observed pH-induced change in the lifetime in mCardinal with its molecular properties. While the chromophores of both protein variants are stabilized by the same number of hydrogen bonds, it was found that the chromophore in mCardinal exhibits more water contacts compared to mNeptune. In mCardinal, interaction between the chromophore and Glu-145 is reduced as compared to mNeptune, but interaction with Thr-147 which is Ser-147 in mNeptune is stronger in mCardinal. Therefore, the dynamics of the excited-state proton transfer (ESPT) might be different in mCardinal and mNeptune. The pH dependency of ESPT is suggested as a key mechanism for pH sensitivity.

Plant crude extracts containing oligomeric hemagglutinins protect chickens against highly Pathogenic Avian Influenza Virus after one dose of immunization

Highly pathogenic avian influenza viruses (HPAIV) have been responsible for causing several severe outbreaks across the world. To protect poultry farms and to prevent the possible spread of new influenza pandemics, vaccines that are both efficacious and low-cost are in high demand. We produced stable, large hemagglutinin H5 oligomers in planta by the specific interaction between S•Tag and S•Protein. H5 oligomers combined via S•Tag::S•Protein interaction in plant crude extracts induced strong humoral immune responses, strong neutralizing antibody responses, and resistance in chickens after challenge with a wild type HPAIV H5 virus strain. In all three parameters, plant crude extracts with H5 oligomers induced better responses than crude extracts containing trimers. The neutralizing antibodies induced by by two-dose and one dose immunization with an adjuvanted crude extract containing H5 oligomer protected vaccinated chickens from two lethal H5N1 virus strains with the efficiency of 92% and 100%, respectively. Following housing vaccinated chickens together with ten non-immunized chickens, only one of these chickens had detectable levels of the H5N1 virus. To facilitate the easy storage of a candidate vaccine, the H5 oligomer crude extracts were mixed with adjuvants and stored for 3.5 and 5.5 months at 4 °C, and chickens were immunized with these crude extracts. All these vaccinated chickens survived after a lethal H5N1 virus challenge. H5 oligomer crude extracts are comparable to commercial vaccines as they also induce strong virus-neutralizing immune responses following the administration of a single dose. The cost-effective production of plant crude extract vaccine candidates and the high stability after long-term storage will enable and encourage the further exploration of this technology for veterinary vaccine development.

Production of Influenza H5 Vaccine Oligomers in Plants

The transient expression of veterinary vaccines in plants is a promising tool because of its low cost connected with a practically unlimited scale-up. To achieve these goals, two major challenges, high immunogenicity of vaccines and minimal of down-stream processing cost, have to be overcome. Here we present and discuss protocols enabling to generate highly immunogenic H5 influenza candidate vaccines as H5 oligomers, by transient expression in Nicotiana benthamiana plants and to perform analytical experiments as Western blot, ELISA, and hemagglutination and hemagglutination inhibition assays.

Sex differences in quality of life after stroke were explained by patient factors, not clinical care: evidence from the Australian Stroke Clinical Registry

BACKGROUND AND PURPOSE

Women may receive stroke care less often than men. We examined the contribution of clinical care on sex differences and health-related quality of life (HRQoL) after stroke.

METHODS

We included first-ever strokes registered in the Australian Stroke Clinical Registry (2010-2014) with HRQoL assessed between 90 and 180 days after onset (EQ-5D-3L instrument) that were linked to hospital administrative data (up to 2013). Study factors included sociodemographics, comorbidities, walking ability on admission (stroke severity proxy) and clinical care (e.g. stroke unit care). Responses to the EQ-5D-3L were transformed into a total utility value (-0.516 'worse than death' to 1 'best' health). Quantile regression models, adjusted for confounding factors, were used to determine median differences (MD) in utility scores by sex.

RESULTS

Approximately 60% (6852/11 418) of stroke survivors had an EQ-5D-3L assessment (median 139 days; 44% female). Compared with men, women were older (median age 77.1 years vs. men 71.2 years) and fewer could walk on admission (37.9% vs. men 46.1%, P < 0.001). Women had lower utility values than men, and the difference was explained by age and stroke severity, but not clinical care [MD_{adjusted =} -0.039, 95% confidence interval: -0.056, -0.021]. Poorer HRQoL was observed in younger men (aged <65 years), particularly those with more comorbidities, and in older women (aged ≥75 years).

CONCLUSIONS

Stroke severity and comorbidities contribute to the poorer HRQoL in young men and older women. Further studies are needed to understand age-sex interaction to better inform treatments for different subgroups and ensure evidence-based treatments to reduce the severity of stroke are prioritized.

Immunization with Plant-Derived Multimeric H5 Hemagglutinins Protect Chicken against Highly Pathogenic Avian Influenza Virus H5N1

Since 2003, H5N1 highly pathogenic avian influenza viruses (HPAIV) have not only caused outbreaks in poultry but were also transmitted to humans with high mortality rates. Vaccination is an efficient and economical means of increasing immunity against infections to decrease the shedding of infectious agents in immunized animals and to reduce the probability of further infections. Subunit vaccines from plants are the focus of modern vaccine developments. In this study, plant-made hemagglutinin (H5) trimers were purified from transiently transformed N. benthamiana plants. All chickens immunized with purified H5 trimers were fully protected against the severe HPAIV H5N1 challenge. We further developed a proof-of-principle approach by using disulfide bonds, homoantiparallel peptides or homodimer proteins to combine H5 trimers leading to production of H5 oligomers. Mice vaccinated with crude leaf extracts containing H5 oligomers induced neutralizing antibodies better than those induced by crude leaf extracts containing trimers. As a major result, eleven out of twelve chickens (92%) immunized with adjuvanted H5 oligomer crude extracts were protected from lethal disease while nine out of twelve chickens (75%) vaccinated with adjuvanted H5 trimer crude extracts survived. The solid protective immune response achieved by immunization with crude extracts and the stability of the oligomers form the basis for the development of inexpensive protective veterinary vaccines.

Plant-Derived Trimeric CO-26K-Equivalent Epitope Induced Neutralizing Antibodies Against Porcine Epidemic Diarrhea Virus

Porcine epidemic diarrhea virus (PEDV) is a causative agent of a highly infectious disease with a high mortality rate, especially in newborn piglets in Asian countries resulting in serious economic loss. The development of a rapid, safe, effective and cost-efficient vaccine is crucial to protect pigs against PEDV infection. The COE antigen is regarded to be a major target for subunit vaccine development against PEDV infection. The naturally assembled COE protein forms a homotrimeric structure. In the present study, we successfully produced a trimeric COE protein as a native structure by fusion with the C-terminal isoleucine zipper trimerization (GCN4pII) motif in Nicotiana benthamiana, with a high expression level shown via semi-quantified Western blots. Trimeric COE protein was purified via immobilized metal affinity chromatography (IMAC), and its trimeric structure was successfully demonstrated by a cross-linking reaction, and a native PAGE gel. A crude extract containing the COE trimer was used for evaluating immunogenicity in mice. After 1 and 2 booster immunizations, the crude extract containing trimeric COE elicited elevated PEDV-specific humoral responses, as demonstrated by ELISA and Western blot analyses. Notably, a virus-neutralizing antibody assay indicated that the neutralization activities of sera of mice vaccinated with the crude extract containing COE-GCN4pII were similar to those of mice vaccinated with a commercial vaccine. These results suggest that crude extract containing trimeric COE is a promising plant-based subunit vaccine candidate for PEDV prevention.

In vitro-Formulated Oligomers of Strep-Tagged Avian Influenza Haemagglutinin Produced in Plants Cause Neutralizing Immune Responses

The worldwide emergence of the novel influenza A H5N1 and H5N8 has notably and directly impacted the poultry industry, resulting in the need for effective and cheap vaccination strategies to protect poultry worldwide. Subunit vaccines from plants can be produced for a low cost, and plant production systems are easily scaled up at low infrastructure cost. However, subunit vaccines generally induce low immunogenicity against influenza. To address this issue, we present a new and innovative method to generate highly immunogenic H5 oligomers. The method is based on specific and high-affinity interaction between engineered streptavidin (Strep-Tactin® XT) and the Strep-tag II peptide. H5-Strep-tag II-tagged trimers were produced via transient agroinfection in tobacco leaves and purified, and oligomers were formulated in vitro by adding purified homotetrameric Strep-Tactin® XT. Immunogenicity was tested by performing mouse immunizations. Haemagglutinin oligomers produced in vitro by combining Strep-Tactin® XT and Strep-tag II-fused haemagglutinin trimers from plants raised potentially neutralizing antibodies in mice. Vaccines based on actual H5N1 haemagglutinin can be produced by combining strep-tagged haemagglutinin trimers from plants and Strep-Tactin® XT.

Neutralizing immune responses induced by oligomeric H5N1-hemagglutinins from plants

Plant-based transient expression is an alternative platform to produce hemagglutinin-based subunit vaccines. This production system provides not only fast and effective response in the context of a pandemic but also enables the supply of big volume vaccines at low cost. Crude plant extracts containing influenza hemagglutinin are considered to use as vaccine sources because of avoidance of related purification steps resulting in low cost production allowing veterinary applications. Highly immunogenic influenza hemagglutinins are urgently required to meet these pre-conditions. Here, we present a new and innovative way to generate functional H5 oligomers from avian flu hemagglutinin in planta by the specific interaction of S·Tag and S·Protein. A S·Tag was fused to H5 trimers and this construct was transiently co-expressed in planta with S·Protein-TPs which was multimerized by disulfide bonds via cysteine residues in tailpiece sequences (TP) of IgM antibody. Multimerized S·Protein-TPs serve as bridges/molecular docks to combine S·Tag-fused hemagglutinin trimers to form very large hemagglutinin H5 oligomers. H5 oligomers in the plant crude extract were highly active in hemagglutination resulting in high titers. Immunization of mice with two doses of plant crude extracts containing H5 oligomers after storage for 1 week at 4 °C caused strong immune responses and induced neutralizing specific humoral immune responses in mice. These results allow for the development of cheap influenza vaccines for veterinary application in future.

Plant-Based Vaccine Antigen Production

The transient and stable expression of potentially therapeutic proteins in plants is a promising tool for the efficient production of vaccines and antibodies at low cost connected with a practically unlimited scale-up. To achieve these goals, two major challenges, inadequate production levels and non-scalable purification technologies, have to be overcome. Here we present and discuss protocols enabling to perform influenza vaccine production by transient expression in tobacco plants, to perform analytical experiments as Western blot, ELISA, and hemagglutination assays and to purify the antigens by classical affinity chromatography and scalable membrane-based Inverse Transition Cycling.

Influence of elastin-like polypeptide and hydrophobin on recombinant hemagglutinin accumulations in transgenic tobacco plants

Fusion protein strategies are useful tools to enhance expression and to support the development of purification technologies. The capacity of fusion protein strategies to enhance expression was explored in tobacco leaves and seeds. C-terminal fusion of elastin-like polypeptides (ELP) to influenza hemagglutinin under the control of either the constitutive CaMV 35S or the seed-specific USP promoter resulted in increased accumulation in both leaves and seeds compared to the unfused hemagglutinin. The addition of a hydrophobin to the C-terminal end of hemagglutinin did not significantly increase the expression level. We show here that, depending on the target protein, both hydrophobin fusion and ELPylation combined with endoplasmic reticulum (ER) targeting induced protein bodies in leaves as well as in seeds. The N-glycosylation pattern indicated that KDEL sequence-mediated retention of leaf-derived hemagglutinins and hemagglutinin-hydrophobin fusions were not completely retained in the ER. In contrast, hemagglutinin-ELP from leaves contained only the oligomannose form, suggesting complete ER retention. In seeds, ER retention seems to be nearly complete for all three constructs. An easy and scalable purification method for ELPylated proteins using membrane-based inverse transition cycling could be applied to both leaf- and seed-expressed hemagglutinins.

Veterinary vaccines from transgenic plants: highlights of two decades of research and a promising example

In the last two decades the development of efficient plant-based expression strategies and new concepts for the purification of recombinant proteins prompted the application of plant-derived vaccines for veterinary purposes. The expression of recombinant proteins in plants possesses advantages over conventional eukaryotic expression systems and therefore represents a versatile tool for the production of "edible" and "seasonal" vaccines. This review aims to provide an overview about the expression of vaccines using transgenic plants for veterinary medicine with the focus on increasing the amount of the recombinant proteins as well as concepts for their efficient purification. ELPylation of recombinant proteins is one strategy for on one side boosting the amount of the recombinant protein and on the other side simplifying its purification. This up-and-coming tool was applied for the development of effective production and purification strategies for antigens against Avian Flu, a very important animal disease with a strong economic impact. Future perspectives of plant-based veterinary vaccines in the context of purification and economy are also discussed within this article.

Membrane-based inverse transition cycling: an improved means for purifying plant-derived recombinant protein-elastin-like polypeptide fusions

Elastin-like peptide (ELP) was fused to two different avian flu H5N1 antigens and expressed in transgenic tobacco plants. The presence of the ELP tag enhanced the accumulation of the heterologous proteins in the tobacco leaves. An effective membrane-based Inverse Transition Cycling was developed to recover the ELPylated antigens and antibodies from plant material. The functionality of both the ELPylated neuraminidase and an ELPylated nanobody was demonstrated.

Fetus in fetu: a case report and literature review

Fetus in fetu is a rare condition in which a fetiform calcified mass often is present in the abdomen of its host, a newborn or an infant. We report on a case of a 19-month-old girl whose plain abdominal radiograph, ultrasonography, and computed tomography scan revealed a mass in which the contents favor a fetus in fetu rather than a teratoma. The noncalcified vertebral column invisible on the radiographs was identified by the pathologist; therefore, the nonvisualization of the vertebral axis on radiography or on computed tomography scan does not exclude the diagnosis of fetus in fetu.

Partial failure of sternal fusion in an adolescent

We describe the case of an adolescent girl who had an isolated cranial sternal cleft without any associated abnormalities; the cleft had been well tolerated since her birth. A review of the literature shows that such cases are uncommon. In such cases, surgery is only for cosmetic reasons.

Mediastinal lipomatosis

Mediastinal lipomatosis is a benign condition characterized by a large amount of mature adipose tissue within the mediastinum. It widens the mediastinum and may simulate mass lesions, thus leading to diagnostic errors. We describe a new case of a huge mediastinal lipomatosis and review 36 cases previously reported in the literature. Computed tomography has an important role in the diagnosis of this disease. To avoid invasive and unnecessary procedures, this diagnosis should be considered in any patient with Cushing's syndrome.

[Endobronchial lipoma: apropos of a case with dual localization]

Endobronchial lipoma is an uncommon benign tumor. It is composed of fat tissue and is visible on CT scanner. We report an unusual case of a patient who developed two endobronchial lipomas. The first lipoma was removed 10 years earlier. We emphasize the contribution of computed tomography in the diagnosis of endobronchial lipoma. Cases of multiple lipomas are very scarce in the literature.