Preliminary evaluation of a thermosensitive chitosan hydrogel for Echinococcus granulosus vaccine delivery

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.

Immunological evaluation of a recombinant vaccine delivered with an analogous hyaluronic acid chitosan nanoparticle-hydrogel against Toxoplasma gondii in mice

BACKGROUND

Toxoplasma gondii (T. gondii) is not only a threat to the public health but it also poses adverse impacts on the livestock industry. This study aimed to develop a recombinant vaccine composed of T. gondii microneme protein 6 (TgMIC6) and T. gondii rhoptry protein 18 (TgROP18).The vaccine was delivered with a novel vector, named analogous hyaluronic acid chitosan nanoparticle-hydrogel (AHACNP-HG) and its immune protection was evaluated.

METHODS

The recombinant MIC6 and ROP18 proteins were obtained by affinity chromatography and loaded onto AHACNP-HG by magnetic stirring. The characterizations of AHACNP-HG were investigated, including its structure, rheological property, nanoparticle size and zeta potential, its ability to release protein in vitro and toxicology in vivo. The immunological and anti-infection effects of AHACNP-HG/rMIC6/rROP18 were examined in the mice model.

RESULTS

AHACNP-HG presented a characteristic of composite system and possessed biosecurity with excellent protein control-release property. AHACNP-HG/rMIC6/rROP18 vaccine enhanced a mixed Th1/Th2 cellular immune response accompanied by an increased level of the cytokines, IFN-γ and IL-10. It also provoked a stronger humoral immune response. Additionally, after challenge with T. gondii tachyzoite, AHACNP-HG/rMIC6/rROP18 inoculation prolonged the survival time of mice.

CONCLUSION

Our data indicated that mixed rMIC6 and rROP18 induced strong immune response and played a certain protective role in controlling T. gondii infection, and the novel adjuvant AHACNP-HG improved modestly some immunogenicity properties in mouse model, which indicated that it can be used as a novel delivery system in vaccine development.

Multi-Omic Profiling, Structural Characterization, and Potent Inhibitor Screening of Evasion-Related Proteins of a Parasitic Nematode, Haemonchus contortus, Surviving Vaccine Treatment

The emergence of drug-resistant parasitic nematodes in both humans and livestock calls for development of alternative and cost-effective control strategies. Barbervax^® is the only registered vaccine for the economically important ruminant strongylid Haemonchus contortus. In this study, we compared the microbiome, genome-wide diversity, and transcriptome of H. contortus adult male populations that survived vaccination with an experimental vaccine after inoculation in sheep. Our genome-wide SNP analysis revealed 16 putative candidate vaccine evasion genes. However, we did not identify any evidence for changes in microbial community profiling based on the 16S rRNA gene sequencing results of the vaccine-surviving parasite populations. A total of fifty-eight genes were identified as significantly differentially expressed, with six genes being long non-coding (lnc) RNAs and none being putative candidate SNP-associated genes. The genes that highly upregulated in surviving parasites from vaccinated animals were associated with GO terms belonging to predominantly molecular functions and a few biological processes that may have facilitated evasion or potentially lessened the effect of the vaccine. These included five targets: astacin (ASTL), carbonate dehydratase (CA2), phospholipase A2 (PLA2), glutamine synthetase (GLUL), and fatty acid-binding protein (FABP3). Our tertiary structure predictions and modelling analyses were used to perform in silico searches of all published and commercially available inhibitor molecules or substrate analogs with potential broad-spectrum efficacy against nematodes of human and veterinary importance.

Long-Term Vaccine Delivery and Immunological Responses Using Biodegradable Polymer-Based Carriers

Biodegradable polymers are largely employed in the biomedical field, ranging from tissue regeneration to drug/vaccine delivery. The biodegradable polymers are highly biocompatible and possess negligible toxicity. In addition, biomaterial-based vaccines possess adjuvant properties, thereby enhancing immune responses. This Review introduces the use of different biodegradable polymers and their degradation mechanism. Different kinds of vaccines, as well as the interaction between the carriers with the immune system, then are highlighted. Natural and synthetic biodegradable micro-/nanoplatforms, hydrogels, and scaffolds for local or targeted and controlled vaccine release are subsequently discussed.

Identification of combined T-cell and B-cell reactive Echinococcus granulosus 95 antigens for the potential development of a multi-epitope vaccine

Background

Identification of combined T-cell and B-cell reactive Eg95 antigens for the potential development of a multi-epitope vaccine against Echinococcus granulosus (EG), the causative agent of cystic echinococcosis (CE).

Methods

This study involved the recombinant expression of Eg95 along with associated immune rabbit antiserum preparation. Bioinformatics technology was used to facilitate the analysis of Eg95 molecules. PCR was subsequently used to amplify genetic sequences of the epitopes encoding the T-cell and B-cell reactive peptide fragments. SDS-PAGE was used to assess the expression levels of three proteins. Eg95 serum and patient antiserum, which were assessed using Western blot in order to identify suitable antigenic epitope peptides. ELISA detection assay facilitated comparison of the immune reactivity of the short peptide epitopes. The assay results could be used to determine an EG epitope-based vaccine candidate list from suitably reactive Eg95 epitopes.

Results

Eg95 molecules have 3 T-B table. The phage display systems were successfully built using the M13KE carrier. Expression of the three fusion protein peptides were detected. Western blot showed Eg95 antiserum against EG facilitated identification of the three T-cell and B-cell reactive epitopes. After the reaction intensities analyzed by the ELISA, both of the short peptide epitopes Eg95-2 and Eg95-3 showed strong signal strength and associated antigenicity when combined with patient serum and rabbit anti-rEg95 serum.

Conclusions

This study used bioinformatics methods to construct successfully a T-cell and B-cell epitope phage display system for the Eg95 antigen from EG. The two epitopes of Eg95-2 and Eg95-3 demonstrated strong antigenicity with potential applications for peptide vaccine development.

Smart thermosensitive chitosan hydrogel for nasal delivery of ibuprofen to treat neurological disorders

BACKGROUND

The in-situ gelation of thermosensitive nasal formulations with desirable spray characteristics at room temperature and ability to undergo a phase change to a semi-solid state with mucoadhesive behavior at physiological temperature has the potential to efficiently deliver therapeutics to brain. However, their application in nasal spray generation with favorable characteristics has not been investigated.

METHODS

Thermosensitive chitosan (CS)-based formulations with different viscosities were prepared for intranasal delivery of ibuprofen using CS of various molecular weights. The formulation developed was optimized with regards to its physicochemical, rheological, biological properties and the generated aerosol characteristics.

RESULTS

The formulations showed rapid gelation (4-7 min) at 30-35°C, which lies in the human nasal cavity temperature spectrum. The decrease in CS molecular weight to 110-150 kDa led to generation of optimum spray with lower Dv₅₀, wider spray area, and higher surface area coverage. This formulation also showed improved ibuprofen solubility that is approximately 100× higher than its intrinsic aqueous solubility, accelerated ibuprofen transport across human nasal epithelial cells and transient modulation of tight junctions.

CONCLUSIONS

A thermosensitive CS-based formulation has been successfully developed with suitable rheological properties, aerosol performance and biological properties that is beneficial for nose-to-brain drug delivery.