IRES-based co-expression of influenza virus conserved genes can promote synergistic antiviral effects both in vitro and in vivo

2A and 2A-like Sequences: Distribution in Different Virus Species and Applications in Biotechnology

2A is an oligopeptide sequence that mediates a ribosome “skipping” effect and can mediate a co-translation cleavage of polyproteins. These sequences are widely distributed from insect to mammalian viruses and could act by accelerating adaptive capacity. These sequences have been used in many heterologous co-expression systems because they are versatile tools for cleaving proteins of biotechnological interest. In this work, we review and update the occurrence of 2A/2A-like sequences in different groups of viruses by screening the sequences available in the National Center for Biotechnology Information database. Interestingly, we reported the occurrence of 2A-like for the first time in 69 sequences. Among these, 62 corresponded to positive single-stranded RNA species, six to double stranded RNA viruses, and one to a negative-sense single-stranded RNA virus. The importance of these sequences for viral evolution and their potential in biotechnological applications are also discussed.

Toward a universal influenza virus vaccine: Some cytokines may fulfill the request

The influenza virus annually causes widespread damages to the health and economy of the global community. Vaccination is currently the most crucial strategy in reducing the number of patients. Genetic variations, the high diversity of pandemic viruses, and zoonoses make it challenging to select suitable strains for annual vaccine production. If new pandemic viruses emerge, it will take a long time to produce a vaccine according to the new strains. In the present study, intending to develop a universal influenza vaccine, new bicistronic DNA vaccines were developed that expressed NP or NPm antigen with one of modified IL-18/ IL-17A/ IL-22 cytokine adjuvants. NPm is a mutant form of the antigen that has the ability for cytoplasmic accumulation. In order to investigate and differentiate the role of each of the components of Th1, Th2, Th17, and Treg cellular immune systems in the performance of vaccines, Treg competent and Treg suppressed mouse groups were used. Mice were vaccinated with Foxp3-FC immunogen to produce Treg suppressed mouse groups. The potential of the vaccines to stimulate the immune system was assessed by IFN-γ/IL-17A Dual FluoroSpot. The vaccine's ability to induce humoral immune response was determined by measuring IgG1, IgG2a, and IgA-specific antibodies against the antigen. Kinetics of Th1, Th2, and Th17 cellular immune responses after vaccination, were assessed by evaluating the expression changes of IL-17A, IFN-γ, IL-18, IL-22, IL-4, and IL-2 cytokines by semi-quantitative real-time RT-PCR. To assess the vaccines' ability to induce heterosubtypic immunity, challenge tests with homologous and heterologous viruses were performed and then the virus titer was measured in the lungs of animals. Evaluation of the data obtained from this study showed that the DNA-vaccines coding NPm have more ability to induces a potent cross-cellular immune response and protective immunity than DNA-vaccines coding NP. Although the use of IL-18/ IL-17A/ IL-22 genetic adjuvants enhanced immune responses and protective immunity, Administration of NPm in combination with modified IL-18 (Igk-mIL18-IgFC) induced the most effective immunity in Treg competent mice group.

Co-expression of Interleukin-17A molecular adjuvant and prophylactic Helicobacter pylori genetic vaccine could cause sterile immunity in Treg suppressed mice

The increasing clinical significance of Helicobacter pylori (H. pylori) in human stomach cancer has led to global efforts to eradicate this pathogen. Recent studies have confirmed the importance of some cytokines such as Interleukin-18 (IL-18), Interleukin-8 (IL-8), Interleukin-17A (IL-17A) and Interleukin-22 (IL-22) in the pathogenesis of the so-called bacterium. This study was designed to compare the effects of Type 1T helper (Th1), Type 2T helper (Th2) cells, Regulatory T cells (Treg) and T helper 17 (Th17) modulatory effects on the efficacy of designed H. pylori vaccine by incorporating some molecular adjuvants in Treg competent and Treg suppressed groups. A bicistronic vector was used for simultaneous expression of codon-optimized Outer inflammatory protein a (OipA) gene and modified mice IL-18, IL-17A, IL-22 and Foxp3 (forkhead box P3) cytokines from four cassettes. Immunization of mice groups was performed using produced plasmids intradermally. Specific IgG1 and IgG2 and IgA antibody titers produced in mice were confirmed by enzyme-linked immunosorbent assay (ELISA) in sera and intestine obtained four weeks after the last immunization. After being stimulated with a mixture of both anti-CD28 mAb and H. pylori lysate, frequencies of single Interferon-Gamma (IFN-γ), single IL-17 and dual IFN-γ/IL-17-secreting T-cells were documented using dual-color FluoroSpot. The kinetics of Th1, Th2 and Th17 in the immunized animals was determined by relative quantification of IL-17A, IL-22, IFN-γ, IL-8, IL-2 and IL-4 specific mRNAs. Four weeks after bacterial challenge, quantitative colony count in the isolated and homogenized stomachs was utilized to assess the level of protective immunity among all groups. The results of immunologic assays showed that the highest cell-mediated immunity cytokines were produced in IL-17 receiving group in which the Treg responses were suppressed previously by the administration of the Foxp3 as an immunogen. In addition, potent clearance of Helicobacter pylori infection was seen in this group as well.

Production and Application of Multicistronic Constructs for Various Human Disease Therapies

The development of multicistronic vectors has opened up new opportunities to address the fundamental issues of molecular and cellular biology related to the need for the simultaneous delivery and joint expression of several genes. To date, the examples of the successful use of multicistronic vectors have been described for the development of new methods of treatment of various human diseases, including cardiovascular, oncological, metabolic, autoimmune, and neurodegenerative disorders. The safety and effectiveness of the joint delivery of therapeutic genes in multicistronic vectors based on the internal ribosome entry site (IRES) and self-cleaving 2A peptides have been shown in both in vitro and in vivo experiments as well as in clinical trials. Co-expression of several genes in one vector has also been used to create animal models of various inherited diseases which are caused by mutations in several genes. Multicistronic vectors provide expression of all mutant genes, which allows the most complete mimicking disease pathogenesis. This review comprehensively discusses multicistronic vectors based on IRES nucleotide sequence and self-cleaving 2A peptides, including its features and possible application for the treatment and modeling of various human diseases.