Development of orf virus as a bifunctional recombinant vaccine: Surface display of Echinococcus granulosus antigen EG95 by fusion to membrane structural proteins

The cooperation between orf virus and Staphylococcus aureus leads to intractable lesions in skin infection

A large amount of evidence shows that different kinds of microorganisms can jointly cope with environmental pressures including cell hosts. For example, in many cases, it has been found that secondary or mixed infection of animals caused by ORFV (an epitheliophilic Parapoxvirus) and bacteria (such as Staphylococcus aureus or Streptococcus) shows a mutual aid mode that indirectly leads to the deterioration of the disease. However, the lack of research on the co-pathogenic mechanism, including how to hijack and destroy the cell host in the pathological microenvironment, has hindered the in-depth understanding of the pathogenic process and consequences of this complex infection and the development of clinical treatment methods. Here, we summarized the current strategies of trapping cell hosts together, based on the previously defined ORFV-Host (O-H) system. The opportunistic invasion of S. aureus destroyed the delicate dynamic balance of the O-H, thus aggravating tissue damage through bacterial products (mediated by Agr), even causing sepsis or inducing cytokine storms. In fact, the virus products from its adaptive regulatory system (VARS) weaken the immune attacks and block molecular pathways, so that S. aureus can settle there more smoothly, and the toxins can penetrate into local tissues more quickly. This paper focuses on the main challenges faced by cell hosts in dealing with mixed infection, which provides a starting point for us to deal with this disease in the future.

Promising Technologies in the Field of Helminth Vaccines

Helminths contribute a larger global burden of disease than both malaria and tuberculosis. These eukaryotes have caused human infections since before our earliest recorded history (i.e.: earlier than 1200 B.C. for Schistosoma spp.). Despite the prevalence and importance of these infections, helminths are considered a neglected tropical disease for which there are no vaccines approved for human use. Similar to other parasites, helminths are complex organisms which employ a plethora of features such as: complex life cycles, chronic infections, and antigenic mimicry to name a few, making them difficult to target by conventional vaccine strategies. With novel vaccine strategies such as viral vectors and genetic elements, numerous constructs are being defined for a wide range of helminth parasites; however, it has yet to be discussed which of these approaches may be the most effective. With human trials being conducted, and a pipeline of potential anti-helminthic antigens, greater understanding of helminth vaccine-induced immunity is necessary for the development of potent vaccine platforms and their optimal design. This review outlines the conventional and the most promising approaches in clinical and preclinical helminth vaccinology.

Contagious ecthyma: how serious is the disease worldwide?

Contagious ecthyma (CE) is an infectious disease of small ruminants caused by a parapoxvirus of family Poxviridae subfamily Chordopoxvirinae. The disease is obviously distinguished by an establishment of scabby lesions and ulcerative formation on less hairy areas including muzzle, ears, nostril, and sometimes on genitalia. The disease is endemic in sheep and goats. The virus is transmissible to other ruminants and is a public health concern in humans. Although the disease is known as self-limiting, it may cause a significant economic threat and financial losses due to lower productivity in livestock production. Information with regard to the risk of the disease and epidemiology in most parts of the world is underreported. This paper aims to provide relevant information about the epidemiology of CE in selected regions of Europe, South America, North America, Asia, Africa, and Australia. An in-depth comprehension of virus infection, diagnoses, and management of the disease will enable farmers, researchers, veterinarians, abattoir workers, health personnel, and border controllers to improve their measures, skills, and effectiveness toward disease prevention and control, toward reducing unnecessary economic loss among farmers. A herd health program for significant improvement in management and productivity of livestock demands a well planned extension program that ought to encourage farmers to equip themselves with adequate skills for animal healthcare.

Selection of chromatographic methods for the purification of cell culture-derived Orf virus for its application as a vaccine or viral vector

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Estimation of the isoelectric point and size of Vero cell-derived Orf virus.

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Limited dynamic binding capacity of tested Orf virus to sulfated cellulose.

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Purification of Orf virus by steric exclusion chromatography lead to 84 % recovery.

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Hydrophobic interaction chromatography suitable for Orf virus purification.

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Promising unit operations for a scalable DSP to produce Orf virus viral vectors.

In recent years, the Orf virus has become a promising tool for protective recombinant vaccines and oncolytic therapy. However, suitable methods for an Orf virus production, including up- and downstream, are very limited. The presented study focuses on downstream processing, describing the evaluation of different chromatographic unit operations. In this context, ion exchange-, pseudo-affinity- and steric exclusion chromatography were employed for the purification of the cell culture-derived Orf virus, aiming at a maximum in virus recovery and contaminant depletion. The most promising chromatographic methods for capturing the virus particles were the steric exclusion- or salt-tolerant anion exchange membrane chromatography, recovering 84 % and 86 % of the infectious virus. Combining the steric exclusion chromatography with a subsequent Capto™ Core 700 resin or hydrophobic interaction membrane chromatography as a secondary chromatographic step, overall virus recoveries of up to 76 % were achieved. Furthermore, a complete cellular protein removal and a host cell DNA depletion of up to 82 % was possible for the steric exclusion membranes and the Capto™ Core 700 combination.

The study reveals a range of possible unit operations suited for the chromatographic purification of the cell culture-derived Orf virus, depending on the intended application, i.e. a human or veterinary use, and the required purity.

The re-emerging of orf virus infection: A call for surveillance, vaccination and effective control measures

Orf disease is known to be enzootic among small ruminants in Asia, Africa, and some other parts of the world. The disease caused by orf virus is highly contagious among small ruminant species. Unfortunately, it has been neglected for decades because of the general belief that it only causes a self-limiting disease. On the other hand, in the past it has been reported to cause huge cumulative financial losses in livestock farming. Orf disease is characterized by localized proliferative and persistent skin nodule lesions that can be classified into three forms: generalized, labial and mammary or genitals. It can manifest as benign or malignant types. The later type of orf can remain persistent, often fatal and usually causes a serious outbreak among small ruminant population. Morbidity and mortality rates of orf are higher especially in newly infected kids and lambs. Application of antibiotics together with antipyretic and/or analgesic is highly recommended as a supportive disease management strategy for prevention of subsequent secondary microbial invasion. The presence of various exotic orf virus strains of different origin has been reported in many countries mostly due to poorly controlled cross-border virus transmission. There have been several efforts to develop orf virus vaccines and it was with variable success. The use of conventional vaccines to control orf is a debatable topic due to the concern of short term immunity development. Following re-infection in previously vaccinated animals, it is uncommon to observe the farms involved to experience rapid virus spread and disease outbreak. Meanwhile, cases of zoonosis from infected animals to animal handler are not uncommon. Despite failures to contain the spread of orf virus by the use of conventional vaccines, vaccination of animals with live orf virus is still considered as one of the best choice. The review herein described pertinent issues with regard to the development and use of potential effective vaccines as a control measure against orf virus infection.

Strategies for design of improved biocatalysts for industrial applications

Biocatalysts are creating increased interest among researchers due to their unique properties. Several enzymes are efficiently produced by microorganisms. However, the use of natural enzymes as biocatalysts is hindered by low catalytic efficiency and stability during various industrial processes. Many advanced enzyme technologies have been developed to reshape the existing natural enzymes to reduce these limitations and prospecting of novel enzymes. Frequently used enzyme technologies include protein engineering by directed evolution, immobilisation techniques, metagenomics etc. This review summarizes recent and emerging advancements in the area of enzyme technologies for the development of novel biocatalysts and further discusses the future directions in this field.

Deletion of the Chemokine Binding Protein Gene from the Parapoxvirus Orf Virus Reduces Virulence and Pathogenesis in Sheep

Orf virus (ORFV) is the type species of the Parapoxvirus genus of the family Poxviridae and infects sheep and goats, often around the mouth, resulting in acute pustular skin lesions. ORFV encodes several secreted immunomodulators including a broad-spectrum chemokine binding protein (CBP). Chemokines are a large family of secreted chemotactic proteins that activate and regulate inflammation induced leukocyte recruitment to sites of infection. In this study we investigated the role of CBP in vivo in the context of ORFV infection of sheep. The CBP gene was deleted from ORFV strain NZ7 and infections of sheep used to investigate the effect of CBP on pathogenesis. Animals were either infected with the wild type (wt) virus, CBP-knockout virus or revertant strains. Sheep were infected by scarification on the wool-less area of the hind legs at various doses of virus. The deletion of the CBP gene severely attenuated the virus, as only few papules formed when animals were infected with the CBP-knock-out virus at the highest dose (10⁷ p.f.u). In contrast, large pustular lesions formed on almost all animals infected with the wt and revertant strains at 10⁷ p.f.u. The lesions for the CBP-knock-out virus resolved approximately 5–6 days p.i, at a dose of 10⁷ pfu whereas in animals infected with the wt and revertants at this dose, lesions began to resolve at approximately 10 days p.i. Few pustules developed at the lowest dose of 10³ p.f.u. for all viruses. Immunohistochemistry of biopsy skin-tissue from pustules showed that the CBP-knockout virus replicated in all animals at the highest dose and was localized to the skin epithelium while haematoxylin and eosin staining showed histological features of the CBP-knockout virus typical of the parent virus with acanthosis, elongated rete ridges and orthokeratotic hyperkeratosis. MHC-II immunohistochemistry analysis for monocytes and dendritic cells showed greater staining within the papillary dermis of the CBP-knock-out virus compared with the revertant viruses, however this was not the case with the wt where staining was similar. Our results show that the CBP gene encodes a secreted immunodulator that has a critical role in virulence and pathogenesis.

Current Technological Improvements in Enzymes toward Their Biotechnological Applications

Enzymes from extremophiles are creating interest among researchers due to their unique properties and the enormous power of catalysis at extreme conditions. Since community demands are getting more intensified, therefore, researchers are applying various approaches viz. metagenomics to increase the database of extremophilic species. Furthermore, the innovations are being made in the naturally occurring enzymes utilizing various tools of recombinant DNA technology and protein engineering, which allows redesigning of the enzymes for its better fitment into the process. In this review, we discuss the biochemical constraints of psychrophiles during survival at the lower temperature. We summarize the current knowledge about the sources of such enzymes and their in vitro modification through mutagenesis to explore their biotechnological potential. Finally, we recap the microbial cell surface display to enhance the efficiency of the process in cost effective way.

Autodisplay of an archaeal γ-lactamase on the cell surface of Escherichia coli using Xcc_Est as an anchoring scaffold and its application for preparation of the enantiopure antiviral drug intermediate (-) vince lactam

At present, autotransporter protein mediated surface display has opened a new dimension in the development of whole-cell biocatalysts. Here, we report the identification of a novel autotransporter Xcc_Est from Xanthomonas campestris pv campestris 8004 by bioinformatic analysis and application of Xcc_Est as an anchoring motif for surface display of γ-lactamase (Gla) from thermophilic archaeon Sulfolobus solfataricus P2 in Escherichia coli. The localization of γ-lactamase in the cell envelope was monitored by Western blot, activity assay and flow cytometry analysis. Either the full-length or truncated Xcc_Est could efficiently transport γ-lactamase to the cell surface. Compared with the free enzyme, the displayed γ-lactamase exhibited optimum temperature of 30 °C other than 90 °C, with a substantial decrease of 60 °C. Under the preparation system, the engineered E. coli with autodisplayed γ-lactamase converted 100 g racemic vince lactam to produce 49.2 g (-) vince lactam at 30 °C within 4 h. By using chiral HPLC, the ee value of the produced (-) vince lactam was determined to be 99.5 %. The whole-cell biocatalyst exhibited excellent stability under the operational conditions. Our results indicate that the E. coli with surface displayed γ-lactamase is an efficient and economical whole cell biocatalyst for preparing the antiviral drug intermediate (-) vince lactam at mild temperature, eliminating expensive energy cost performed at high temperature.

Animal poxvirus vaccines: a comprehensive review

The family Poxviridae includes several viruses of medical and veterinary importance. Global concerted efforts combined with an intensive mass-vaccination campaign with highly efficaceious live vaccine of vaccinia virus have led to eradication of smallpox. However, orthopoxviruses affecting domestic animals continue to cause outbreaks in several endemic countries. Different kinds of vaccines starting from conventional inactivated/attenuated to recombinant protein-based vaccines have been used for control of poxvirus infections. Live virus homologous vaccines are currently in use for diseases including capripox, parapox, camelpox and fowlpox, and these vaccines are highly effective in eliciting (with the exception of parapoxviruses) long-lasting immunity. Attenuated strains of poxviruses have been exploited as vectored vaccines to deliver heterologous immunogens, many of them being licensed for use in animals. Worthy of note are vaccinia virus, fowlpox virus, capripoxvirus, parapoxvirus and canary pox, which have been successfully used for developing new-generation vaccines targeting many important pathogens. Remarkable features of these vaccines are thermostability and their ability to engender both cellular and humoral immune responses to the target pathogens. This article updates the important vaccines available for poxviruses of livestock and identifies some of the research gaps in the present context of poxvirus research.