In recent years, peptide/protein drugs have attracted considerable attention owing to their superior targeting and therapeutic effect and fewer side effects compared with chemical drugs. Oral administration modality with enhanced patient compliance is increasingly being recognized as an ideal route for peptide/protein delivery. However, the limited permeation efficiency and low oral bioavailability of peptide/protein drugs significantly hinder therapeutic advances. To address these problems, various nano and microscale delivery platforms have been developed, which offer significant advantages in oral peptide/protein delivery. In this review, we briefly introduce the transport mechanisms of oral peptide/protein delivery and the primary barriers to this delivery process. We also highlight the recent advances in various nano and microscale delivery platforms designed for oral peptide/protein delivery. We then summarize the existing strategies used in these delivery platforms to improve the oral bioavailability and permeation efficiency of peptide/protein therapeutics. Finally, we discuss the major challenges faced when nano and microscale systems are used for oral peptide/protein delivery. This review is expected to provide critical insight into the design and development of oral peptide/protein delivery systems with significant therapeutic advances.

Nano and microscale delivery platforms for enhanced oral peptide/protein bioavailability.

Potency and efficacy of VP20-based vaccine against tilapia lake virus using different prime-boost vaccination regimens in tilapia

Prophylactic vaccine delivery systems against epidemic infectious diseases.

Shiga toxins (Stxs) are classic bacterial toxins and major virulence factors of toxigenic Shigella dysenteriae and enterohemorrhagic Escherichia coli (EHEC). These toxins recognize a glycosphingolipid globotriaosylceramide (Gb3/CD77) as their receptor and inhibit protein synthesis in cells by cleaving 28S ribosomal RNA. They are the major cause of life-threatening complications such as hemolytic uremic syndrome (HUS), associated with severe cases of EHEC infection, which is the leading cause of acute kidney injury in children. The threat of Stxs is exacerbated by the lack of toxin inhibitors and effective treatment for HUS. Here, we briefly summarize the Stx structure, subtypes, in vitro and in vivo models, Gb3 expression and HUS, and then introduce recent studies using CRISPR-Cas9-mediated genome-wide screens to identify the host cell factors required for Stx action. We also summarize the latest progress in utilizing and engineering Stx components for biomedical applications.

Shiga Toxins: An Update on Host Factors and Biomedical Applications.

Strategies to enhance, suppress, or qualitatively shape the immune response are of importance for diverse biomedical applications, such as the development of new vaccines, treatments for autoimmune diseases and allergies, strategies for regenerative medicine, and immunotherapies for cancer. However, the intricate cellular and molecular signals regulating the immune system are major hurdles to predictably manipulating the immune response and developing safe and effective therapies. To meet this challenge, biomaterials are being developed that control how, where, and when immune cells are stimulated in vivo, and that can finely control their differentiation in vitro. We review recent advances in the field of biomaterials for immunomodulation, focusing particularly on designing biomaterials to provide controlled immunostimulation, targeting drugs and vaccines to lymphoid organs, and serving as scaffolds to organize immune cells and emulate lymphoid tissues. These ongoing efforts highlight the many ways in which biomaterials can be brought to bear to engineer the immune system.

Biomaterial Strategies for Immunomodulation

Recombinant HcpA-EspA-Tir-Stx2B chimeric protein induces immunity against attachment and toxicity of Escherichia coli O157:H7.

Vaccine delivery vehicles are just as important in vaccine efficiency. Through the progress in nanotechnology, various nanoparticles have been evaluated as carriers for these substances. Among them, alginate nanoparticles are a good choice because of their biodegradability, biocompatibility, ease of production, etc. In this study, feasibility of alginate nanoparticles (NPs) such as recombinant LTB from Enterotoxigenic Escherichia coli (ETEC) carrier was investigated. To do this, the eltb gene was cloned and expressed in E. coli BL21 (DE3) host cells, and a Ni-NTA column purified the protein. NPs were achieved through ion gelation method in the presence of LTB protein and CaCl2 as the cross-Linker and NPs were characterized physicochemically. Balb/C mice groups were immunized with LTB-entrapped NPs or LTB with adjuvant and immunogenicity was assessed by evaluating IgG titer. Finally, the neutralization of antibodies was evaluated by GM1 binding and loop assays. LTB protein was expressed and efficiently entrapped into the alginate NPs. The size of NPs was less than 50 nm, and entrapment efficiency was 80%. Western blotting showed maintenance of the molecular weight and antigenicity of the released protein from NPs. Administration of LTB-entrapped NPs stimulated antibody responses in immunized mice. Immunization induced protection against LT toxin of ETEC in ileal loops and inhibits enterotoxin binding to GM1-gangliosides. Alginate NPs are also appropriate vehicle for antigen delivery purpose. Moreover because of their astonishing properties, they have the potential to serve as an adjuvant.

Entrapment of LTB protein in alginate nanoparticles protects against Enterotoxigenic Escherichia coli.

Entrapment of HETS recombinant protein onto PLGA and alginate NPs improves the immunogenicity of the protein against E. coli O157:H7.

Objective(s): Enterotoxigenic Escherichia coli (ETEC) is known as the most common bacterial causes of diarrheal diseases related to morbidity and mortality. Heat-labile enterotoxin (LT) is a part of major virulence factors in ETEC pathogenesis. Antigen entrapment into nanoparticles (NPs) can protect them and enhance their immunogenicity.Materials and Methods: In the present study, recombinant LTB protein was expressed in E. coli BL21 (DE3) and purified by an Ni-NTA agarose column. The protein was entrapped in PLGA polymer by the double emulsion method. NPs were characterized physicochemically and the protein release from the NPs was evaluated. ELISA assay was performed for investigation of raised antibody against the recombinant protein in mice. The anti-toxicity and anti-adherence attributes of the immune sera against ETEC were also evaluated.Results: It showed the successful cloning of a 313 bp DNA fragment encoding LTB protein in the pET28a vector. Over-expression in BL21 (DE3) led to the formation of corresponding 15.5 kDa protein bands in the SDS-PAGE gel. Western blotting by using anti-CTX confirmed the purified LTB. Protein-entrapped NPs had a spherical shape with the size of 238 nm mean diameter and 85% entrapment efficiency.  Immunological analyses showed the production of a high titer of specific IgG antibody in immunized animals. The neutralizing antibody in the sera of immunized animals was approved by GM1 binding and Ileal loop assays.Conclusion: The results indicate the efficacy of the entrapped LTB protein as an effective immunogen which induces the humoral responses.

https://ijbms.mums.ac.ir/article_10545_abc4c98e982432fb8391d05f1a9faaf5.pdf

An LTB-entrapped protein in PLGA nanoparticles preserves against enterotoxin of enterotoxigenic Escherichia coli .

Enterohemorrhagic Escherichia coli (EHEC) strains are foodborne pathogens with importance in public health. The lack of effective clinical treatment, sequelae after infection and mortality rate in humans confirms the essential need for prophylactic and vaccines approaches. EspA, Tir, HcpA and Stx2 are major virulence factors for adherence and toxicity of EHEC, so an appropriate tetravalent immunogen consist of toxin subunit and crucial colonization factors was selected and constructed. Bioinfo[1]rmatic analyses of recombinant construction such as sequences choosing and optimizing, mRNA folding, physicochemical property in 2D and 3D structures, besides other immunoinformatics data like B-cell and T-cell epitopes and allergenicity of chimera were some reported according to the reliable servers. In silico assessment of the chimeric proteins demonstrated the desired model has a proper mRNA features, besides acceptable stability and solubility. This model is close to native proteins topologically, and all domains were found to have a high antigenic competency and surface accessibility. These results can be beneficial for the development of a chimeric immunogen against adherence and toxicity of EHEC in an animal model application.

http://www.biotechrep.ir/article_69002_20641f04c3b8c5cef52dca278cddc16f.pdf

Emad Kordbacheh

Papers

Recombinant HcpA-EspA-Tir-Stx2B chimeric protein induces immunity against attachment and toxicity of Escherichia coli O157:H7.

Entrapment of LTB protein in alginate nanoparticles protects against Enterotoxigenic Escherichia coli.

Entrapment of HETS recombinant protein onto PLGA and alginate NPs improves the immunogenicity of the protein against E. coli O157:H7.

An LTB-entrapped protein in PLGA nanoparticles preserves against enterotoxin of enterotoxigenic Escherichia coli .

In Silico Analysis of a Multi-subunit Immunogen, Targeting Virulence Factors of Enterohemorrhagic Escherichia coli