Preparation and immunological effectiveness of a swine influenza DNA vaccine encapsulated in chitosan nanoparticles. Vaccine. 2011;29:8549-8556. [PMID: 21945253 DOI: 10.1016/j.vaccine.2011.09.029]

Chitosan non-particulate vaccine delivery systems

Chitosan is an extensively used polymer for drug delivery applications in particulate and non-particulate carriers. Chitosan-based particulate, nano-, and microparticle, carriers have been the most extensively studied for the delivery of therapeutics and vaccines. However, chitosan has also been used in vaccine applications for its adjuvant properties in various hydrogels or as a carrier coating material. The focus of this review will be on the usage of chitosan as a vaccine adjuvant based on its intrinsic immunogenicity; the various forms of chitosan-based non-particulate delivery systems such as thermosensitive hydrogels, microneedles, and conjugates; and the advantages of its role as a coating material for vaccine carriers.

Outlining recent updates on influenza therapeutics and vaccines: A comprehensive review

Influenza virus has presented a considerable healthcare challenge during the past years, particularly in vulnerable groups with compromised immune systems. Therapeutics and vaccination have always been in research annals since the spread of influenza. Efforts have been going on to develop an antiviral therapeutic approach that could assist in better disease management and reduce the overall disease complexity, resistance development, and fatality rates. On the other hand, vaccination presents a chance for effective, long-term, cost-benefit, and preventive response against the morbidity and mortality associated with the influenza. However, the issues of resistance development, strain mutation, antigenic variability, and inability to cure wide-spectrum and large-scale strains of the virus by available vaccines remain there. The article gathers the updated data for the therapeutics and available influenza vaccines, their mechanism of action, shortcomings, and trials under clinical experimentation. A methodological approach has been adopted to identify the prospective therapeutics and available vaccines approved and within the clinical trials against the influenza virus. Review contains influenza therapeutics, including traditional and novel antiviral drugs and inhibitor therapies against influenza virus as well as research trials based on newer drug combinations and latest technologies such as nanotechnology and organic and plant-based natural products. Most recent development of influenza vaccine has been discussed including some updates on traditional vaccination protocols and discussion on next-generation and upgraded novel technologies. This review will help the readers to understand the righteous approach for dealing with influenza virus infection and for deducing futuristic approaches for novel therapeutic and vaccine trials against Influenza.

Main Aspects of Pharmaceutical Development of In situ Immunobiological Drugs for Intranasal Administration

INTRODUCTION

The review presents the latest developments in the area of intranasal in situ delivery systems of immunobiological drugs (IBDs). Interest in intranasal administration for IBDs has increased significantly due to the COVID-19 pandemic. However, not only intranasal delivery of vaccines is developing, but also bacteriophages, interferons, etc. In situ systems that make a selective phase transition can be a modern solution to intranasal delivery problems caused by mucociliary clearance. In addition, smart-polymers used as the main excipients in in situ systems can be used as specific adjuvants.

METHODS

A scientific search was conducted on the PubMed database of medical publications for the period from 2000 to 2022, using the keywords "intranasal in situ vaccine"; "intranasal in situ immunization". There were analyzed in detail more than 70 scientific studies on intranasal in situ delivery of IBDs.

RESULTS AND CONCLUSIONS

Despite the large number of new studies, the potential of possibilities of intranasal in situ systems is not being realized. Based on the results of the literature review an algorithm was created for the development of in situ systems for intranasal delivery of IBDs. Such algorithms and the methods of study design organization described in the review will help to facilitate the R&D process and bring the drug to commercial market, which will help to improve the quality of medical care.

Screening the potential part of the G protein antigen is an achievable strategy to improve the immune effect of DNA vaccine against MSRV infection

DNA vaccines, as an effective prophylactic technology to induce both humoral and cellular immune responses, have already been widely studied to prevent and control viral and bacterial infections in aquaculture. To find a more effective and safer way to control Micropterus salmoides rhabdovirus (MSRV) infection in largemouth bass, two different DNA vaccines expressing partial (pcDNA3.1-G2) and full-length (pcDNA3.1-G) of the MSRV G protein were developed and injected intramuscularly with different doses. The immune effect was comprehensively compared and evaluated by detecting immune-related parameters including serum antibody levels, immune-related physiological indexes, immune-related gene expression and relative survival rates in this study. The results showed that compared with the pcDNA3.1-G vaccine, the pcDNA3.1-G2 vaccine induced higher serum antibody levels, a lower nonspecific immune response in serum (ACP, SOD and T-AOC activities), higher immune-related gene expression and a higher relative survival rate. Moreover, the immune effect of pcDNA3.1-G2-vaccinated fish showed gradually higher with the increasing pcDNA3.1-G2 concentration, especially in pcDNA3.1-G2 (10μg/per fish) group, the relative survival rate reached to 82.5%, which was significant higher (p < 0.05) than pcDNA3.1-G (10μg/per fish) group. This study indicated that screening the potential core part of an antigen is an achievable strategy to improve the immunogenicity and immunoprotective effect of DNA vaccine.

[In situ gels as a modern method of intranasal vaccine delivery]

The continuous emergence of new pathogens and the evolution of microbial drug resistance make it absolutely necessary to develop innovative, effective vaccination strategies. Use of nasal vaccination can increase convenience, safety, cause both local and systemic immune reactions. Intranasal administration nevertheless has a number of shortcomings that can be overcome by using the latest achievements of pharmaceutical science. One of the aspects of such solution may be the use of systems for the production of intranasal vaccines in situ polymer compositions that provide a directed sol-gel transition controlled by the physiological conditions of the nasal cavity. At the same time, the gelation of the administered dose in contact with the nasal mucosa involves prolonged exposure of the drug at the injection site, greater mucoadhesion, counteraction to mucociliary clearance, modified and more complete release. A number of both foreign and domestic manufacturers produces polymers such as chitosan, gums, polyoxyethylene and polyoxypropylene block copolymers (poloxamers, proxanols), carbomers. For effective pharmaceutical development of new intranasal IBD delivery systems corresponding to the QbD concept, not only the knowledge of the range of excipients is necessary, but also simple, accessible, and reproducible methods for determining indicators that define the critical parameters of such delivery systems. In accordance with the conducted scientific search, the main indicators of standardization of in situ intranasal systems were identified: temperature and time of gel formation, gel strength, rheological characteristics, mucoadhesion, release, nasal mucociliary clearance time.

Preparation of Fluorescently Labeled Chitosan-Quercetin Drug-Loaded Nanoparticles with Excellent Antibacterial Properties

In recent years, quercetin plays an increasingly important role in the medical field. However, the absorption and effect of quercetin as a drug in vivo are limited due to its extremely poor solubility in water. In addition, chitosan nanoparticles can deliver poorly soluble drugs as drug delivery carriers. Herein, chitosan nanoparticles were prepared by oxidative degradation and ionic cross-linking technology to study the drug loading properties of quercetin. On the other hand, the application of chitosan for fluorescent materials can improve the biocompatibility of fluorescent materials and increase the adsorption of fluorescent materials. Fluorescently labeled chitosan nanoparticles, especially chitosan microsphere fluorescent probes prepared using the abundant amino groups on chitosan chains to react with fluorescein isothiocyanate (FTIC), have been widely used as fluorescent probes in biomarkers and medical diagnostics. Therefore, chitosan–quercetin (CS–QT) drug-loaded nanoparticles are labeled with FITC, and the drug-loaded rate, encapsulation efficiency, and antioxidant properties were investigated. The drug-loaded rate of the sample reaches 8.39%, the encapsulation rate reaches 83.65%, and exhibits good antioxidant capacity. The fluorescence aperture of the obtained sample was consistent with the inhibition zone, which could realize the visualization of the antibacterial performance of the sample. The fluorescent-labeled nano-system exhibit superior antibacterial properties, which provide a strategy for observing the release and function of drugs.

A review of the antiviral activity of Chitosan, including patented applications and its potential use against COVID-19

Chitosan is an abundant organic polysaccharide, which can be relatively easily obtained by chemical modification of animal or fungal source materials. Chitosan and its derivatives have been shown to exhibit direct antiviral activity, to be useful vaccine adjuvants and to have potential anti-SARS-CoV-2 activity. This thorough and timely review looks at the recent history of investigations into the role of chitosan and its derivatives as an antiviral agent and proposes a future application in the treatment of endemic SARS-CoV-2.

Carbohydrates-based diagnosis, prophylaxis and treatment of infectious diseases: Special emphasis on COVID-19

COVID-19 pandemic is taking a dangerous turn due to unavailability of approved and effective vaccines and therapy. Currently available diagnostic techniques are time-consuming, expensive, and maybe impacted by the mutations produced in the virus. Therefore, investigation of novel, rapid, and economic diagnosis techniques, prophylactic vaccines and targeted efficacious drug delivery systems as treatment strategy is imperative. Carbohydrates are essential biomolecules which also act as markers in the realization of immune systems. Moreover, they exhibit antiviral, antimicrobial, and antifungal properties. Carbohydrate-based vaccines and therapeutics including stimuli sensitive systems can be developed successfully and used effectively to fight COVID-19. Thus, carbohydrate-based diagnostic, prophylactic and therapeutic alternatives could be promising to defeat COVID-19 propitiously. Morphology of SARS-CoV-2 and its relevance in devising combat strategies has been discussed. Carbohydrate-based approaches for tackling infectious diseases and their importance in the design of various diagnostic and treatment modalities have been reviewed.

Which one of the thermal approaches (heating DNA or cells) enhances the gene expression in mammalian cells?

OBJECTIVES

Heat treatment as a physical method could increase the cellular uptake of nucleic acids. In this study, the effects of heat shock were evaluated to enhance the transfection efficiency of three plasmid DNAs into HeLa and TC-1 cancerous, and HEK-293 T and Vero non-cancerous cell lines using lipofectamine 2000 reagent.

METHODS

Two methods of cell- and DNA-based heat treatment were used. Heating DNA solution was performed at 94 °C for 5, 10 and 15 min, and also 72 °C for 30, 60 and 120 min, individually. Moreover, heating the cells was done by incubation at 42 °C for 2 h in different times such as before, during and after DNA transfection.

RESULTS

Our data showed that the conformation of plasmid DNAs was changed at different temperatures with increasing time. The heat-treated plasmid DNAs (94 °C for 10 min or 72 °C for 30 min) indicated higher transfection efficiency than untreated plasmid DNAs (p < 0.05). Furthermore, heat treatment of cells before and during the transfection was higher than untreated cells (p < 0.01). Our results demonstrated that DNA transfection efficiency in cancerous cells was less than non-cancerous cells (p < 0.01).

CONCLUSION

Generally, these findings showed that transfection mediated by thermal stimulation could enhance gene transfection in mammalian cell lines.

Evaluating the Anticarcinogenic Activity of Surface Modified/Functionalized Nanochitosan: The Emerging Trends and Endeavors

Chitosan begins its humble journey from marine food shell wastes and ends up as a versatile nutraceutical. This review focuses on briefly discussing the antioxidant activity of chitosan and retrospecting the accomplishments of chitosan nanoparticles as an anticarcinogen. The various modified/functionalized/encapsulated chitosan nanoparticles and nanoforms have been listed and their biomedical deliverables presented. The anticancer accomplishments of chitosan and its modified composites have been reviewed and presented. The future of surface modified chitosan and the lacunae in the current research focus have been discussed as future perspective. This review puts forth the urge to expand the scientific curiosity towards attempting a variety of functionalization and surface modifications to chitosan. There are few well known modifications and functionalization that benefit biomedical applications that have been proven for other systems. Being a biodegradable, biocompatible polymer, chitosan-based nanomaterials are an attractive option for medical applications. Therefore, maximizing expansion of its bioactive properties are explored. The need for applying the ideal functionalization that will significantly promote the anticancer contributions of chitosan nanomaterials has also been stressed.

N-2-Hydroxypropyl Trimethyl Ammonium Chloride Chitosan as Adjuvant Enhances the Immunogenicity of a VP2 Subunit Vaccine against Porcine Parvovirus Infection in Sows

Porcine parvovirus (PPV) is the most important infectious agent causing infertility in pigs, which can be prevented by routine vaccination. Successful vaccination depends on the association with potent adjuvants that can enhance the immunogenicity of antigen and activate the immune system. Polysaccharide adjuvant has low toxicity and high safety, and they can enhance the humoral, cellular and mucosal immune responses. In the present study, we prepared the VP2 protein subunit vaccine against PPV (PPV/VP2/N-2-HACC) using water-soluble N-2-Hydroxypropyl trimethyl ammonium chloride chitosan (N-2-HACC) as the vaccine adjuvant, and the ability of the PPV/VP2/N-2-HACC to induce immune responses and protect sows from PPV infection was evaluated. In vivo immunization showed that the sows immunized with the PPV/VP2/N-2-HACC by intramuscular injection produced higher HI antibody levels and long-term immune protection compared with the other groups, while the subunit vaccine did not stimulate the proliferation of CD4+ and CD8+ T lymphocytes to trigger the secretion of higher levels of IL-2, IL-4, IFN-α, IFN-β, and IFN-γ, indicating that the PPV/VP2/N-2-HACC mainly induced humoral immunity rather than cellular immunity. PPV was not detected in the viscera of the sows immunized with the PPV/VP2/N-2-HACC, and the protective efficacy was 100%. Collectively, our findings suggested that the N-2-HACC was a potential candidate adjuvant, and the PPV/VP2/N-2-HACC had immense application value for the control of PPV.

Intranasal immunization with O-2'-Hydroxypropyl trimethyl ammonium chloride chitosan nanoparticles loaded with Newcastle disease virus DNA vaccine enhances mucosal immune response in chickens

Background

There has been a great interest in developing strategies for enhancing antigen delivery to the mucosal immune system as well as identifying mucosal active immunostimulating agents. To elevate the potential of O-2ʹ-Hydroxypropyl trimethyl ammonium chloride chitosan (O-2ʹ-HACC) as an adjuvant and mucosal immune delivery carrier for DNA vaccine, we prepared the O-2ʹ-HACC loaded with Newcastle disease virus (NDV) F gene plasmid DNA and C3d6 molecular adjuvant (O-2ʹ-HACC/pFDNA microparticles).

Results

The O-2ʹ-HACC/pFDNA exhibited a regular spherical morphology with a particle size of 202.3 ± 0.52 nm, a zeta potential of 50.8 ± 8.21 mV, encapsulation efficiency of 90.74 ± 1.10%, and a loading capacity of 49.84 ± 1.20%. The plasmid DNA could be sustainably released from the O-2ʹ-HACC/pFDNA after an initial burst release. Intranasal vaccination of chickens immunized with O-2ʹ-HACC/pFDNA not only induced higher anti-NDV IgG and sIgA antibody titers but also significantly promoted lymphocyte proliferation and produced higher levels of IL-2, IL-4, IFN-γ, CD4+, and CD8 + T lymphocytes compared with the NDV commercial live attenuated vaccine. Intranasal delivery of the O-2ʹ-HACC/pFDNA enhanced humoral, cellular, and mucosal immune responses and protected chickens from the infection of highly virulent NDV compared with the intramuscular delivery.

Conclusions

Collectively, our findings indicated that the O-2ʹ-HACC could be used as a vaccine adjuvant and delivery system for mucosal immunity and have an immense application promise.

Graphic Abstract

Green Synthesized Chitosan/Chitosan Nanoforms/Nanocomposites for Drug Delivery Applications

Chitosan has become a highlighted polymer, gaining paramount importance and research attention. The fact that this valuable polymer can be extracted from food industry-generated shell waste gives it immense value. Chitosan, owing to its biological and physicochemical properties, has become an attractive option for biomedical applications. This review briefly runs through the various methods involved in the preparation of chitosan and chitosan nanoforms. For the first time, we consolidate the available scattered reports on the various attempts towards greens synthesis of chitosan, chitosan nanomaterials, and chitosan nanocomposites. The drug delivery applications of chitosan and its nanoforms have been reviewed. This review points to the lack of systematic research in the area of green synthesis of chitosan. Researchers have been concentrating more on recovering chitosan from marine shell waste through chemical and synthetic processes that generate toxic wastes, rather than working on eco-friendly green processes-this is projected in this review. This review draws the attention of researchers to turn to novel and innovative green processes. More so, there are scarce reports on the application of green synthesized chitosan nanoforms and nanocomposites towards drug delivery applications. This is another area that deserves research focus. These have been speculated and highlighted as future perspectives in this review.

Chitin and chitosan on the nanoscale

In a matter of decades, nanomaterials from biomass, exemplified by nanocellulose, have rapidly transitioned from once being a subject of curiosity to an area of fervent research and development, now reaching the stages of commercialization and industrial relevance. Nanoscale chitin and chitosan, on the other hand, have only recently begun to raise interest. Attractive features such as excellent biocompatibility, antibacterial activity, immunogenicity, as well as the tuneable handles of their acetylamide (chitin) or primary amino (chitosan) functionalities indeed display promise in areas such as biomedical devices, catalysis, therapeutics, and more. Herein, we review recent progress in the fabrication and development of these bio-nanomaterials, describe in detail their properties, and discuss the initial successes in their applications. Comparisons are made to the dominant nanocelluose to highlight some of the inherent advantages that nanochitin and nanochitosan may possess in similar application.

Enhanced immunogenicity of foot and mouth disease DNA vaccine delivered by PLGA nanoparticles combined with cytokine adjuvants

Although the immunogenicity of DNA vaccines is nonideal, they are still considered as potential alternative vaccine candidates to conventional vaccines. Various DNA delivery systems, including nanoparticles, have been extensively explored and validated to further enhance the immunogenicity of DNA vaccines. DNA vaccines are considered as alternative vaccine candidates. Various DNA delivery systems, including nanoparticles, have been extensively explored to enhance the immunogenicity of DNA vaccines. In this study, positively charged Poly (D, l-lactide-co-glycolic acid) (PLGA) nanoparticles were generated and characterized as a delivery system for O-serotype foot-and-mouth DNA vaccine. A recombinant plasmid encoding swine interleukin (IL)-18, IL-2, or granulocyte-macrophage colony-stimulating factor (GM-CSF) gene was introduced into the DNA vaccine to further improve its immunogenicity, which was evaluated in a guinea pig model. PLGA-pVAX-VP013/IL-18 elicited significantly (P = 0.0149) higher FMDV-specific antibody levels than naked DNA before the challenge. The level of neutralizing antibodies induced by PLGA-pVAX-VP013/IL-18, PLGA-pVAX-VP013/IL-2, and PLGA-pVAX-VP013/GM-CSF significantly increased compared with that induced by naked DNA (P < 0.0001). The lymphocyte proliferation assay showed that cellular immunity induced by PLGA-pVAX-VP013/IL-18 and PLGA-pVAX-VP013/GM-CSF was dramatically enhanced compared with that induced by the inactivated vaccine. The protection by PLGA-pVAX-VP013/IL-18 was consistent with that by the inactivated vaccine post-challenge and was followed by PLGA-pVAX-VP013/GM-CSF. Therefore, cationic PLGA nanoparticles can deliver DNA vaccines and induce humoral and cellular immune responses. The co-administration of FMD DNA vaccine with IL-18 formulated with PLGA nanoparticles was the optimal strategy to improve the immunogenicity of FMD DNA vaccines.

Fate of Biodegradable Engineered Nanoparticles Used in Veterinary Medicine as Delivery Systems from a One Health Perspective

The field of veterinary medicine needs new solutions to address the current challenges of antibiotic resistance and the need for increased animal production. In response, a multitude of delivery systems have been developed in the last 20 years in the form of engineered nanoparticles (ENPs), a subclass of which are polymeric, biodegradable ENPs, that are biocompatible and biodegradable (pbENPs). These platforms have been developed to deliver cargo, such as antibiotics, vaccines, and hormones, and in general, have been shown to be beneficial in many regards, particularly when comparing the efficacy of the delivered drugs to that of the conventional drug applications. However, the fate of pbENPs developed for veterinary applications is poorly understood. pbENPs undergo biotransformation as they are transferred from one ecosystem to another, and these transformations greatly affect their impact on health and the environment. This review addresses nanoparticle fate and impact on animals, the environment, and humans from a One Health perspective.

Water-soluble N-2-Hydroxypropyl trimethyl ammonium chloride chitosan enhanced the immunogenicity of inactivated porcine parvovirus vaccine vaccination on sows against porcine parvovirus infection

Porcine parvovirus (PPV) is one of the most common and important virus causes of infectious infertility in swine throughout the world. Inactivated PPV vaccine is broadly used, however, there is no appropriate immunomodulatory adjuvant for enhancing present vaccines and developing new ones. Therefore, in this study, the water-soluble N-2-Hydroxypropyl trimethyl ammonium chloride chitosan (N-2-HACC) was synthesized, the adjuvant potential of chitosan derivative was evaluated in inactivated PPV vaccine. Twenty adult healthy sows were assigned to four groups and vaccinated with synthesized PPV/N-2-HACC, commercial inactivated vaccine, N-2-HACC adjuvant and PBS. After insemination, all sows were challenged with the homologous PPV-H strain. In vivo immunization showed that sows immunized with the PPV/N-2-HACC induced more long-lasting HI antibodies and strong immune responses. Importantly, immunization of PPV/N-2-HACC significantly protected sows from homologous PPV-H strain infection. However, immunization of PPV/N-2-HACC didn't change the level of IL-2, IL-4 and IFN-γ and the production of CD4+, CD8 + T lymphocyte. The results indicated that PPV/N-2-HACC protect PPV infection mainly through enhancing the humoral immunity rather than cellular immunity. In addition, the mummified fetuses were observed from the control groups, but neither of the two vaccine groups. In conclusion, these results suggest that N-2-HACC can be exploited as an effective adjuvant for vaccine development, and the PPV/N-2-HACC are potent immunization candidates against PPV infection.

Enhanced protective immune response of foot-and-mouth disease vaccine through DNA-loaded virus-like particles

Foot-and-mouth disease virus (FMDV) is the etiological agent of a highly contagious disease that affects cloven-hoofed animals. Virus-like particles (VLPs) can induce a robust immune response and deliver DNA and small molecules. In this study, a VLP-harboring pcDNA3.1/P12A3C plasmid was generated, and the protective immune response was characterized. Guinea pigs were injected with VLPs, naked DNA vaccine, DNA-loaded VLPs, or phosphate-buffered saline twice subcutaneously at four-week intervals. Results demonstrated that the VLPs protected the naked DNA from DNase degeneration and delivered the DNA into the cells in vitro. The DNA-loaded VLPs and the VLPs alone induced a similar level of specific antibodies (P > 0.05) except at 49 dpv (P < 0.05). The difference in interferon-γ was consistent with that in specific antibodies. The levels of neutralizing antibodies induced by the DNA-loaded VLPs were significantly higher than those of other samples (P < 0.01). Similarly, the lymphocyte proliferation by using DNA-loaded VLPs was significantly higher than those using other formulas after booster immunization. Vaccination with DNA-loaded VLPs provided higher protection (100%) against viral challenge compared with vaccination with VLPs (75%) and DNA vaccine (25%). This study suggested that VLPs can be used as a delivery carrier for DNA vaccine. In turn, the DNA vaccine can enhance the immune response and prolong the serological duration of the VLP vaccine. This phenomenon contributes in providing complete protection against the FMDV challenge in guinea pigs and can be valuable in exploring novel nonreplicating vaccines and controlling FMD in endemic countries worldwide.

Nanoparticles in influenza subunit vaccine development: Immunogenicity enhancement

The threat of novel influenza infections has sparked research efforts to develop subunit vaccines that can induce a more broadly protective immunity by targeting selected regions of the virus. In general, subunit vaccines are safer but may be less immunogenic than whole cell inactivated or live attenuated vaccines. Hence, novel adjuvants that boost immunogenicity are increasingly needed as we move toward the era of modern vaccines. In addition, targeting, delivery, and display of the selected antigens on the surface of professional antigen-presenting cells are also important in vaccine design and development. The use of nanosized particles can be one of the strategies to enhance immunogenicity as they can be efficiently recognized by antigen-presenting cells. They can act as both immunopotentiators and delivery system for the selected antigens. This review will discuss on the applications, advantages, limitations, and types of nanoparticles (NPs) used in the preparation of influenza subunit vaccine candidates to enhance humoral and cellular immune responses.

Quaternized Chitosan Nanoparticles in Vaccine Applications

Different natural and synthetic biodegradable polymers have been used in vaccine formulations as adjuvant and delivery system but have faced various limitations. Chitosan is a new delivery system with the potential to improve development of nano vaccines and drugs. However, chitosan is only soluble in acidic solutions of low concentration inorganic acids such as dilute acetic acid and dilute hydrochloric acid and in pure organic solvents, which greatly limits its application. Chemical modification of chitosan is an important way to improve its weak solubility. Quaternized chitosan not only retains the excellent properties of chitosan, but also improves its water solubility for a wider application. Recently, quaternized chitosan nanoparticles have been widely used in biomedical field. This review focuses on some quaternized chitosan nanoparticles, and points out the advantages and research direction of quaternized chitosan nanoparticles. As shown by the applications of quaternized chitosan nanoparticles as adjuvant and delivery carrier in vaccines, quaternized chitosan nanoparticles have promising potential in application for the development of nano vaccines in the future.

Dry Formulations Enhanced Mucoadhesive Properties and Reduced Cold Chain Handing of Influenza Vaccines

To alleviate concerns in health security, emergency flu vaccine stockpiles are required for ensuring rapid availability of vaccines when needed. Cold chain preservation, at high cost and risk, is necessary to maintain vaccine efficacy. This study aimed to develop a dry, easily storable formula for influenza vaccine preparation. The formulation with mucoadhesive properties is expected to facilitate rapid delivery via nasal administration. Chitosan, a cationic polymer, was used as cryo-protectant and to promote mucoadhesion. Optimal concentrations and molecular weights of chitosan polymers were screened, with short chain chitosan (10 kDa) being most suitable. H1N1 dry powder, in different formulations, was prepared via freeze-drying. A series of cryo-protectants, trehalose (T), chitosan (C), fetal bovine serum (FBS; F), or a combination of these (TCF), were screened for their effects on prolonging vaccine shelf life. Physicochemical monitoring (particle size and zeta potential) of powders complexed with mucin revealed that the order of cryo-protectant mixing during preparation was of critical importance. Results indicated that the TCF formula retains its activity up to 1 year as indicated by TCID₅₀ analysis. This approach was also successful at prolonging the shelf life of H3N2 vaccine, and has the potential for large-scale implementation, especially in developed countries where long-term storage of vaccines is problematic.

Polysaccharides as vaccine adjuvants

Adjuvant is a substance added to vaccine to improve the immunogenicity of antigens, and it can induce stronger immune responses and reduce the dosage and production cost of vaccine in populations responding poorly to vaccination. Adjuvants in development or in use mainly include aluminum salts, oil emulsions, saponins, immune-stimulating complexes, liposomes, microparticles, nonionic block copolymers, polysaccharides, cytokines and bacterial derivatives. Polysaccharide adjuvants have attracted much attention in the preparation of nano vaccines and nano drugs because natural polysaccharides have the characteristics of intrinsic immunomodulating, biocompatibility, biodegradability, low toxicity and safety. Moreover, it has been proved that a variety of natural polysaccharides possess better immune promoting effects, and they can enhance the effects of humoral, cellular and mucosal immunities. In the present study, we systematically reviewed the recent studies on polysaccharides with vaccine adjuvant activities, including chitosan-based nanoparticles (NPs), glucan, mannose, inulin polysaccharide and Chinese medicinal herb polysaccharide. The application and future perspectives of polysaccharides as adjuvants were also discussed. These findings lay a foundation for the further development of polysaccharide adjuvants. Collectively, more and more polysaccharide adjuvants will be developed and widely used in clinical practice with more in-depth investigations of polysaccharide adjuvants.

An Overview of Chitosan Nanoparticles and Its Application in Non-Parenteral Drug Delivery

The focus of this review is to provide an overview of the chitosan based nanoparticles for various non-parenteral applications and also to put a spotlight on current research including sustained release and mucoadhesive chitosan dosage forms. Chitosan is a biodegradable, biocompatible polymer regarded as safe for human dietary use and approved for wound dressing applications. Chitosan has been used as a carrier in polymeric nanoparticles for drug delivery through various routes of administration. Chitosan has chemical functional groups that can be modified to achieve specific goals, making it a polymer with a tremendous range of potential applications. Nanoparticles (NP) prepared with chitosan and chitosan derivatives typically possess a positive surface charge and mucoadhesive properties such that can adhere to mucus membranes and release the drug payload in a sustained release manner. Chitosan-based NP have various applications in non-parenteral drug delivery for the treatment of cancer, gastrointestinal diseases, pulmonary diseases, drug delivery to the brain and ocular infections which will be exemplified in this review. Chitosan shows low toxicity both in vitro and some in vivo models. This review explores recent research on chitosan based NP for non-parenteral drug delivery, chitosan properties, modification, toxicity, pharmacokinetics and preclinical studies.

Humoral and Cellular Immunogenicity Induced by Avian Influenza A (H7N9) DNA Vaccine in Mice

BACKGROUND

In March 2013, human infection with avian influenza A (H7N9) virus emerged in China, causing serious public health concerns and raising the possibility of avian-source pandemic influenza. Thus, the development of an effective vaccine for preventing and rapidly controlling avian influenza A (H7N9) virus is needed. In this study, we evaluated the immunogenicity of a synthetic DNA vaccine against H7 HA antigens in mice.

MATERIALS AND METHODS

The synthetic consensus H7 HA DNA vaccine (25 or 50 μg) was administered to BALB/c mice at 0, 14, and 28 days by intramuscular injection followed by electroporation. Humoral and cellular immune responses were analyzed in a hemagglutination inhibition test and interferon-gamma enzyme-linked immunospot (ELISpot) assay, respectively.

RESULTS

H7 HA-vaccinated mice showed 100% seroprotection and seroconversion rate against H7N9 reassortant influenza virus after both second and third immunizations. The geometric mean titer by the hemagglutination inhibition test increased with an increasing number of immunizations. However, there was no significant difference in geometric titer between the two groups injected with 25 and 50 μg of H7 HA DNA vaccine after two (79.98 vs. 107.65, P = 0.39) and three (159.96 vs. 215.28, P = 0.18) doses. In addition, the ELISpot assay revealed that administration of H7 HA DNA vaccine induced potent interferon-gamma production from mouse splenocytes.

CONCLUSIONS

This study demonstrated the humoral and cellular immunogenicity of synthetic consensus H7 HA DNA vaccine in mice. This work demonstrates the potential of the H7 HA DNA vaccine as an efficient tool for the rapid control of emerging influenza A (H7N9) virus.

IgA response and protection following nasal vaccination of chickens with Newcastle disease virus DNA vaccine nanoencapsulated with Ag@SiO2 hollow nanoparticles

Newcastle disease caused by ND virus (NDV) is a highly contagious disease of birds. Vaccine for effective protection of poultry animals from NDV infection is urgently needed. Mucosal immunity plays a very important role in the antiviral immune response. In this study, a NDV F gene-containing DNA vaccine encapsulated in Ag@SiO2 hollow nanoparticles (pFDNA-Ag@SiO2-NPs) with an average diameter of 500 nm were prepared to assess the mucosal immune response. These nanoparticles exhibited low cytotoxicity and did not destroy the bioactivity of plasmid DNA, which could be expressed in vitro. The plasmid DNA was sustainably released after an initial burst release. In vivo immunization showed that the intranasal immunization of chickens with pFDNA-Ag@SiO2-NPs induced high titers of serum antibody, significantly promoted lymphocyte proliferation and induced higher expression levels of IL-2 and IFN-γ in a dose-dependent manner. These results indicated that the Ag@SiO2 hollow nanoparticles could serve as an efficient and safe delivery carrier for NDV DNA vaccine to induce mucosal immunity. This study has provided promising results for the further development of mucosal vaccines encapsulated in inorganic nanoparticles.

Micro- and nanoparticulates for DNA vaccine delivery

DNA vaccination has emerged as a promising alternative to traditional protein-based vaccines for the induction of protective immune responses. DNA vaccines offer several advantages over traditional vaccines, including increased stability, rapid and inexpensive production, and flexibility to produce vaccines for a wide variety of infectious diseases. However, the immunogenicity of DNA vaccines delivered as naked plasmid DNA is often weak due to degradation of the DNA by nucleases and inefficient delivery to immune cells. Therefore, biomaterial-based delivery systems based on micro- and nanoparticles that encapsulate plasmid DNA represent the most promising strategy for DNA vaccine delivery. Microparticulate delivery systems allow for passive targeting to antigen presenting cells through size exclusion and can allow for sustained presentation of DNA to cells through degradation and release of encapsulated vaccines. In contrast, nanoparticle encapsulation leads to increased internalization, overall greater transfection efficiency, and the ability to increase uptake across mucosal surfaces. Moreover, selection of the appropriate biomaterial can lead to increased immune stimulation and activation through triggering innate immune response receptors and target DNA to professional antigen presenting cells. Finally, the selection of materials with the appropriate properties to achieve efficient delivery through administration routes conducive to high patient compliance and capable of generating systemic and local (i.e. mucosal) immunity can lead to more effective humoral and cellular protective immune responses. In this review, we discuss the development of novel biomaterial-based delivery systems to enhance the delivery of DNA vaccines through various routes of administration and their implications for generating immune responses.

The protective immunity against grass carp reovirus in grass carp induced by a DNA vaccination using single-walled carbon nanotubes as delivery vehicles

To reduce the lethal hemorrhagic disease caused by grass carp reovirus (GCRV) and improve the production of grass carp, efficient and economic prophylactic measure against GCRV is the most pressing desired for the grass carp farming industry. In this work, a novel SWCNTs-pEGFP-vp5 DNA vaccine linked vp5 recombinant in the form of plasmid pEGFP-vp5 and ammonium-functionalized SWCNTs by a chemical modification method was prepared to enhance the efficacy of a vp5 DNA vaccine against GCRV in juvenile grass carp. After intramuscular injection (1, 2.5 and 5 μg) and bath administration (1, 10, and 20 mg/L), the ability of the different immune treatments to induce transgene expression was analyzed. The results showed that higher levels of transcription and expression of vp5 gene could be detected in muscle tissues of grass carp in SWCNTs-pEGFP-vp5 treatment groups compare with naked pEGFP-vp5 treatment groups. Moreover, antibody levels, immune-related genes, and relative percentage survival were significantly enhanced in fish immunized with SWCNTs-pEGFP-vp5 vaccine. In addition, we found that a good immune protective effect was observed in bath immunization group; which at a concentration of 20 mg/L could reach the similar relative percentage survival (approximately 100%) in injection group at a dose of 5 μg. All these results indicated that ammonium-functionalized SWCNTs could provide extensive application prospect to aquatic vaccine and might be used to vaccinate fish by intramuscular injection or bath administration method.

MicroRNA Replacing Oncogenic Klf4 and c-Myc for Generating iPS Cells via Cationized Pleurotus eryngii Polysaccharide-based Nanotransfection

Induced pluripotent stem cells (iPSCs), resulting from the forced expression of cocktails out of transcription factors, such as Oct4, Sox2, Klf4, and c-Myc (OSKM), has shown tremendous potential in regenerative medicine. Although rapid progress has been made recently in the generation of iPSCs, the safety and efficiency remain key issues for further application. In this work, microRNA 302-367 was employed to substitute the oncogenic Klf4 and c-Myc in the OSKM combination as a safer strategy for successful iPSCs generation. The negatively charged plasmid mixture (encoding Oct4, Sox2, miR302-367) and the positively charged cationized Pleurotus eryngii polysaccharide (CPEPS) self-assembled into nanosized particles, named as CPEPS-OS-miR nanoparticles, which were applied to human umbilical cord mesenchymal stem cells for iPSCs generation after characterization of the physicochemical properties. The CPEPS-OS-miR nanoparticles possessed spherical shape, ultrasmall particle size, and positive surface charge. Importantly, the combination of plasmids Oct4, Sox2, and miR302-367 could not only minimize genetic modification but also show a more than 50 times higher reprogramming efficiency (0.044%) than any other single or possible double combinations of these factors (Oct4, Sox2, miR302-367). Altogether, the current study offers a simple, safe, and effective self-assembly approach for generating clinically applicable iPSCs.

Newcastle disease virus vaccine encapsulated in biodegradable nanoparticles for mucosal delivery of a human vaccine

An overwhelming number of medicines on the market are oral medicine with the disadvantage of lower bioavailability universally. Newcastle disease (ND) has become a serious disease that threatens the poultry industries in many countries, and there are no treatments available for ND. The biodegradable materials could be surface modified and protect antigen or DNA from damage. Furthermore, nanoparticles are also a potential drug delivery with proper size. However, Newcastle disease virus (NDV) vaccines encapsulated in nanoparticles were widely used due to their proved a high safety and induced quicker and better mucosal and humoral immune responses. Here we review the results of mucosal immune delivery system for ND. Due to the safety, low toxicity, and better immunogenicity of the mucosal immune delivery system, our studies provide a clearly view that used the biodegradable materials to research and develop the human vaccines to save more patients' lives. These promising results provide a foundation for testing the approach in humans.

Protective immunity of grass carp immunized with DNA vaccine encoding the vp7 gene of grass carp reovirus using carbon nanotubes as a carrier molecule

The uses of single walled carbon nanotubes (SWCNTs) as carriers for DNA delivery have received considerable attention in cell studies. DNA vaccination of fish has been shown to elicit durable transgene expression, but no reports exist on intramuscular administration of SWCNTs-DNA vaccine electrostatic complexes which prepared through non-covalent conjugation. In this study, we injected grass carp intramuscularly with a plasmid vector containing a major capsid protein gene (vp7) of grass carp reovirus as a) naked pcDNA-vp7, b) SWCNTs-pcDNA-vp7, c) empty plasmid vector, or phosphate buffered saline. After intramuscular administration, the ability of the different immune treatments to induce transgene expression was analyzed. The results indicated that higher levels of transcription and expression of the vp7 gene could be detected in muscle tissues of grass carp 28 days intramuscular injection in SWCNTs-pcDNA-vp7 treatment groups compare with naked pcDNA-vp7 treatment groups. Moreover, the serum respiratory burst activity, complement activity, lysozyme activity, superoxide dismutase activity, immune-related genes, antibody levels and relative percentage survival were significantly enhanced in fish immunized with SWCNTs-pcDNA-vp7 vaccine. The data in this study suggested that SWCNTs were promising carriers for plasmid DNA vaccine and might be used to vaccinate fish by intramuscular approach.

Single-walled carbon nanotubes as candidate recombinant subunit vaccine carrier for immunization of grass carp against grass carp reovirus

Grass carp reovirus (GCRV), the most pathogenic aquareovirus, can cause fatal hemorrhagic disease in fingerling and yearling grass carp. Vaccination by injection is by far the most effective method of combating disease. However it is labor intensive, costly and not feasible to vaccinate large numbers of the fish. Thus, an efficient and economic strategy for the prevention of GCRV infection becomes urgent. Here, functionalized single-walled carbon nanotubes (SWCNTs) as carrier were used to manufacture SWCNTs-VP7 subunit vaccine with chemical modification. Different developmental stages of grass carps were immunized by VP7/SWCNTs-VP7 subunit vaccine against GCRV by intramuscular injection and bath immunization. The results indicate that better immune responses of grass carp immunized with the SWCNTs-VP7 subunit vaccine were induced in comparison with VP7 subunit vaccine alone. Immunization doses/concentrations are significantly reduced (about 5-8 times) to prevent GCRV infection in different developmental stages of grass carp with injection or bath treatment when SWCNTs carrier was used. A good immune protective effect (relative percentage survival greater than 95%) is observed in smaller size fish (0.2 g) with SWCNTs-VP7 bath immunization. In addition, serum respiratory burst activity, complement activity, lysozyme activity, superoxide dismutase activity, alkaline phosphatase activity, immune-related genes and antibody levels were significantly enhanced in fish immunized with vaccine. This study suggested that functionalized SWCNTs was the promising carrier for recombinant subunit vaccine and might be used to vaccinate fish by bath approach.

Chitosan-coated poly(lactic-co-glycolic) acid nanoparticles as an efficient delivery system for Newcastle disease virus DNA vaccine

We determined the efficacy and safety of chitosan (CS)-coated poly(lactic-co-glycolic) acid (PLGA) nanoparticles (NPs) as a delivery system for a vaccine to protect chickens against Newcastle disease virus (NDV). The newly constructed vaccine contained DNA (the F gene) of NDV. The Newcastle disease virus (NDV) F gene deoxyribonucleic acid (DNA) plasmid (pFDNA)-CS/PLGA-NPs were spherical (diameter =699.1±5.21 nm [mean ± standard deviation]) and smooth, with an encapsulation efficiency of 98.1% and a Zeta potential of +6.35 mV. An in vitro release assay indicated that CS controlled the burst release of plasmid DNA, such that up to 67.4% of the entire quantity of plasmid DNA was steadily released from the pFDNA-CS/PLGA-NPs. An in vitro expression assay indicated that the expression of nanoparticles (NPs) was maintained in the NPs. In an immunization test with specific pathogen-free chickens, the pFDNA-CS/PLGA-NPs induced stronger cellular, humoral, and mucosal immune responses than the plasmid DNA vaccine alone. The pFDNA-CS/PLGA-NPs did not harm 293T cells in an in vitro assay and did not harm chickens in an in vivo assay. Overall, the results indicated that CS-coated PLGA NPs can serve as an efficient and safe mucosal immune delivery system for NDV DNA vaccine.

Evaluation of toxicity and adjuvant effects of peptidoglycan microspheres orally administered to mice

In this study, peptidoglycan microspheres were evaluated for their toxicity and adjuvant effects after oral administration to mice. The liver and spleen indexes, CD cell content in peripheral blood and spleen, and immunoglobulin content in peripheral blood were measured by flow cytometry and indirect ELISA, respectively. Peptidoglycan microspheres with a loading capacity of 46.41 ± 0.83 g/100 g were prepared. In vivo tests showed that peptidoglycan microspheres revealed an immuno-enhancing profile as indicated by the slow increase of IgG content in peripheral blood compared with that of the untreated peptidoglycan group. In conclusion, peptidoglycan microspheres may be used as a new oral adjuvant in the host.

Antitumor effect of therapeutic HPV DNA vaccines with chitosan-based nanodelivery systems

Background

Cervical cancer is the second-most-common cause of malignancies in women worldwide, and the oncogenic activity of the human papilloma virus types (HPV) E7 protein has a crucial role in anogenital tumors. In this study, we have designed a therapeutic vaccine based on chitosan nanodelivery systems to deliver HPV-16 E7 DNA vaccine, considered as a tumor specific antigen for immunotherapy of HPV-associated cervical cancer. We have developed a Nano-chitosan (NCS) as a carrier system for intramuscular administration using a recombinant DNA vaccine expressing HPV-16 E7 (NCS-DNA E7 vaccine). NCS were characterized in vitro for their gene transfection ability.

Results

The transfection of CS-pEGFP NPs was efficient in CHO cells and the expression of green fluorescent proteins was well observed. In addition, NCS-DNA E7 vaccine induced the strongest E7-specific CD8+ T cell and interferon γ responses in C57BL/6 mice. Mice vaccinated with NCS-DNA E7 vaccine were able to generate potent protective and therapeutic antitumor effects against challenge with E7-expressing tumor cell line, TC-1.

Conclusions

The strong therapeutic effect induced by the Chitosan-based nanodelivery suggest that nanoparticles may be an efficient carrier to improve the immunogenicity of DNA vaccination upon intramuscular administration and the platform could be further exploited as a potential cancer vaccine candidate in humans.

All-in-one bacmids: an efficient reverse genetics strategy for influenza A virus vaccines

Vaccination is the first line of defense against influenza virus infection, yet influenza vaccine production methods are slow, antiquated, and expensive as a means to effectively reduce the virus burden during epidemic or pandemic periods. There is a great need for alternative influenza vaccines and vaccination methods with a global scale of impact. We demonstrate here a strategy to generate influenza A virus in vivo by using bacmid DNAs. Compared to the classical reverse genetics system, the "eight-in-one" bacmids (bcmd-RGFlu) showed higher efficiency of virus rescue in various cell types. Using a transfection-based inoculation (TBI) system, intranasal delivery to DBA/2J and BALB/c mice of bcmd-RGFlu plus 293T cells led to the generation of lethal PR8 virus in vivo. A prime-boost intranasal vaccination strategy using TBI in the context of a bcmd-RGFlu carrying a temperature-sensitive H1N1 virus resulted in protection of mice against lethal challenge with the PR8 strain. Taken together, these studies provide proof of principle to highlight the potential of vaccination against influenza virus by using in vivo reverse genetics.

IMPORTANCE

Vaccination is the first line of defense against influenza virus infections. A major drawback in the preparation of influenza vaccines is that production relies on a heavily time-consuming process of growing the viruses in eggs. We propose a radical change in the way influenza vaccination is approached, in which a recombinant bacmid, a shuttle vector that can be propagated in both Escherichia coli and insect cells, carries an influenza virus infectious clone (bcmd-RGFlu). Using a surrogate cell system, we found that intranasal delivery of bcmd-RGFlu resulted in generation of influenza virus in mice. Furthermore, mice vaccinated with this system were protected against lethal influenza virus challenge. The study serves as a proof of principle of a potentially universal vaccine platform against influenza virus and other pathogens.

Conserved peptides containing overlapping CD4+ and CD8+ T-cell epitopes in the H1N1 influenza virus: an immunoinformatics approach

Pandemic threats of the H1N1 influenza virus have drawn attention to developing a universal vaccine against circulating and future strains of this virus. An immunoinformatics study was conducted to identify conserved peptides containing CD4+ and CD8+ T-cell epitopes from all the hemagglutinin (HA) and neuraminidase (NA) protein sequences available until February 2013 to cover the seasonal as well as the pandemic strains of the H1N1 virus. In the present study, six different immunoinformatics prediction programs were used in order to define the epitopes. Five conserved peptides of HA and six of NA protein were obtained that contained overlapping CD4+ and CD8+ T-cell epitopes. These identified peptides have a binding affinity for a large number of major histocompatibility complex (MHC) alleles. WHGSNRPWVSF of NA protein is a new peptide whose T-cell response has not been previously reported. Population coverage studies have shown that these peptide fragments have the capacity to induce a potent immune response among individuals from different populations around the world. Hence, these HA and NA peptides may be considered as interesting candidates for vaccine design.

DNA-encapsulated magnesium phosphate nanoparticles elicit both humoral and cellular immune responses in mice

The efficacy of pEGFP (plasmid expressing enhanced green fluorescent protein)-encapsulated PEGylated (meaning polyethylene glycol coated) magnesium phosphate nanoparticles (referred to as MgPi-pEGFP nanoparticles) for the induction of immune responses was investigated in a mouse model. MgPi-pEGFP nanoparticles induced enhanced serum antibody and antigen-specific T-lymphocyte responses, as well as increased IFN-? and IL-12 levels compared to naked pEGFP when administered via intravenous, intraperitoneal or intramuscular routes. A significant macrophage response, both in size and activity, was also observed when mice were immunized with the nanoparticle formulation. The response was highly specific for the antigen, as the increase in interaction between macrophages and lymphocytes as well as lymphocyte proliferation took place only when they were re-stimulated with recombinant green fluorescence protein (rGFP). Thus the nanoparticle formulation elicited both humoral as well as cellular responses. Cytokine profiling revealed the induction of Th-1 type responses. The results suggest DNA-encapsulated magnesium phosphate (MgPi) nanoparticles may constitute a safer, more stable and cost-efficient DNA vaccine formulation.

Epidemic status of Swine influenza virus in china

As one of the most significant swine diseases, in recent years, swine influenza (SI) has had an immense impact on public health and has raised extensive public concerns in China. Swine are predisposed to both avian and human influenza virus infections, between that and/or swine influenza viruses, genetic reassortment could occur. This analysis aims at introducing the history of swine influenza virus, the serological epidemiology of swine influenza virus infection, the clinical details of swine influenza, the development of vaccines against swine influenza and controlling the situation of swine influenza in China. Considering the elaborate nature of swine influenza, a more methodical surveillance should be further implemented.

Preparation and efficacy of Newcastle disease virus DNA vaccine encapsulated in chitosan nanoparticles

Optimal preparation conditions of Newcastle disease virus (NDV) F gene deoxyribonucleic acid (DNA) vaccine encapsulated in chitosan nanoparticles (pFNDV-CS-NPs) were determined. The pFNDV-CS-NPs were prepared according to a complex coacervation method. The pFNDV-CS-NPs were produced with good morphology, high stability, a mean diameter of 199.5 nm, encapsulation efficiency of 98.37%±0.87%, loading capacity of 36.12%±0.19%, and a zeta potential of +12.11 mV. The in vitro release assay showed that the plasmid DNA was sustainably released from the pFNDV-CS-NPs, up to 82.9%±2.9% of the total amount. Cell transfection test indicated that the vaccine expressed the F gene in cells and maintained good bioactivity. Additionally, the safety of mucosal immunity delivery system of the pFNDV-CS-NPs was also tested in vitro by cell cytotoxicity and in vivo by safety test in chickens. In vivo immunization showed that better immune responses of specific pathogen-free chickens immunized with the pFNDV-CS-NPs were induced, and prolonged release of the plasmid DNA was achieved compared to the chickens immunized with the control plasmid. This study lays the foundation for the further development of mucosal vaccines and drugs encapsulated in chitosan nanoparticles.

Preparation and efficacy of Newcastle disease virus DNA vaccine encapsulated in PLGA nanoparticles

Background

Although the Newcastle disease virus (NDV) inactivated vaccines and attenuated live vaccines have been used to prevent and control Newcastle disease (ND) for years, there are some disadvantages. Recently, newly developed DNA vaccines have the potential to overcome these disadvantages. The low delivery efficiency, however, hindered the application of DNA vaccines for ND in practice.

Methodology/Principal Findings

The eukaryotic expression plasmid pVAX1-F (o) DNA that expressed the F gene of NDV encapsulated in PLGA nanoparticles (pFNDV-PLGA-NPs) were prepared by a double emulsion-solvent evaporation method and optimal preparation conditions of the pFNDV-PLGA-NPs were determined. Under the optimal conditions, the pFNDV-PLGA-NPs were produced in good morphology and had high stability with a mean diameter of 433.5±7.5 nm, with encapsulation efficiency of 91.8±0.3% and a Zeta potential of +2.7 mV. Release assay in vitro showed that the fusion gene plasmid DNA could be sustainably released from the pFNDV-PLGA-NPs up to 93.14% of the total amount. Cell transfection test indicated that the vaccine expressed and maintained its bioactivity. Immunization results showed that better immune responses of SPF chickens immunized with the pFNDV-PLGA-NPs were induced compared to the chickens immunized with the DNA vaccine alone. In addition, the safety of mucosal immunity delivery system of the pFNDV-PLGA-NPs was also tested in an in vitro cytotoxicity assay.

Conclusions/Significance

The pFNDV-PLGA-NPs could induce stronger cellular, humoral, and mucosal immune responses and reached the sustained release effect. These results laid a foundation for further development of vaccines and drugs in PLGA nanoparticles.

Availability of polymeric nanoparticles for specific enhanced and targeted drug delivery

Over the past 20–30 years there has been quite a number of studies interested in polymeric nanoparticle (PNP) systems as a pharmaceutical approach for poorly soluble drugs, peptide drugs, gene and antibodies. Now, the products based on the PNP technologies are used in the fields of medical science, pharmaceutical science, tissue engineering and clothing, food and housing. This review focuses attention on PNPs for specific enhanced and targeted drug delivery of therapeutic drugs including peptide drugs as well as drug delivery applications of such systems. Outcomes from recent studies on polymers, how to make PNPs, pharmacokinetics and pharmacodynamics of PNPs, and the release profiles from PNPs and related systems are also described, including their pharmacokinetics and pharmacodynamics, if available. In addition, the latest PNP trends and will be described.