جستجوی مقالات مرتبط با کلیدواژه « dna vaccine » در نشریات گروه « پزشکی »

The advancements in immuno-oncology have created a new and unparalleled opportunity for the advancement of vaccination methods. Therapeutic DNA cancer vaccines are now regarded as an excellent way to stimulate the immune system in its fight against cancer. Lung cancer is well recognized as one of the primary factors leading to patient mortality worldwide. Despite significant advancements in innovative tumor immunotherapy, including the use of immune checkpoint inhibitors or oncolytic viruses, the overall 5-year survival rate of individuals with lung malignancies remains very low. Therefore, there is an urgent need to find efficacious vaccinations for the treatment of lung cancer. DNA vaccines are now regarded as a viable immunotherapy approach to stimulate the host immune system against lung cancer. First, we discuss antigen repertoire selection and delivery strategies to improve cancer vaccines. We summarize the recent advances in DNA vaccines that target lung cancer antigens and highlight their implications for disease treatment.

Vaccines have been one of the most remarkable achievements through medical history and have had a very high positive impact on human health (1). The number of prevented deaths through vaccination is estimated to be about 2-3 million per year (2). Reduction of the risk of many infectious diseases and eradication of smallpox have been the result of intensive immunization programs (3). Given that such health benefits are also translated to economic advantages, the indirect positive outcomes of immunization could be very broad. For instance, lost working days due to different diseases could partly be prevented through vaccination. Thus, despite the huge investments needed for immunization programs, they are usually assumed as cost-effective projects (4).

Helicobacter pylori is one of the most prevalent human infectious agents that is directly involved in various upper digestive tract diseases. Although antibiotics-based therapy and proton pump inhibitors eradicate the bacteria mostly, their effectiveness has been declined recently due to emergence of antibiotic-resistant strains. Development of a DNA vaccine is a promising approach against bacterial pathogens. Genes encoding motility factors are promising immunogens to develop a DNA vaccine against H. pylori infection due to critical role of these genes in bacterial attachment and colonization within the gastric lumen. The present study aimed to synthesize a DNA vaccine construct based on the Flagellin A gene (flaA), the predominant flagellin subunit in H. pylori flagella.

The coding sequence of flaA was amplified through PCR and sub-cloned in the pBudCE4.1 vector. The recombinant vector was introduced into the human dermal fibroblast cells, and its potency to express the flaA protein was analyzed using SDS-PAGE. The recombinant construct was intramuscularly (IM) injected into the mice, and the profiles of cytokines and immunoglobulins were measured using ELISA.

It has been found that flaA was successfully expressed in cells. Recombinant-vector also increased the serum levels of evaluated cytokines and immunoglobulins in mice.

These findings showed that the pBudCE4.1-flaA construct was able to activate the immune responses. This study is the first step towards synthesis of recombinant-construct based on the flaA gene. Immunization with such construct may inhibit the H. pylori-associated infection; however, further experiments are urgent.

Tuberculosis (TB) is believed to be one of the leading causes of death in the world; nevertheless, Bacillus Calmette-Guérin (BCG) is the solitary vaccine utilized to prevent TB. Despite the protective effect of this vaccine in children, its efficiency remains under question in adults. We conducted the present study to provide an overview of DNA based vaccines against TB and highlight the vaccine delivery advances and limitations. This study also aimed to bring a review of mycobacterial antigens, including heat shock protein 65 (Hsp65), antigen 85A (Ag85A), early secretory antigenic target 6 (EAST-6), antigen 85B (Ag85B), and heat shock protein X (HspX) as the most extensively considered antigens in the development of vaccines against M. tuberculosis.

Mycobacterium tuberculosis (M. tuberculosis), an intracellular pathogen, causes 1.5 million deaths globally. Bacilli Calmette-Guérin (BCG) is commonly administered to protect people against M. tuberculosis infection; however, there are some obstacles with this first-generation vaccine. DNA vaccines, the third generation vaccines, can induce cellular immune responses for tuberculosis (TB) protection. In this study, optimized DNA vaccine (pcDNA3.1-Mtb72F) entrapped in poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) was used to achieve higher immunogenicity. Plasmid Mtb72F was formulated in PLGA NPs using double emulsion method in the presence of TB10.4 and/or CpG as an adjuvant. Female BALB/c mice were immunized either with NP-encapsulated Mtb72F or naked Mtb72F with or without each adjuvant, using the BCG-prime DNA boost regimen. These NPs were approximately 250 nm in diameter and the nucleic acid and protein encapsulation efficiency were 80% and 25%, respectively. The NPs smaller than 200 nm are able to promote cellular rather than humoral responses. The immunization with the formulation consisting of Mtb72F DNA vaccine and TB10.4 entrapped in PLGA NPs showed significant immunogenicity and induced predominantly interferon-ɣ (IFN-ɣ) production and higher INF-ɣ/interleukin-4 (IL-4) ratio in the cultured spleen cells supernatant. PLGA NPs loaded with Mtb72F DNA-based vaccine with TB10.4 could be considered as a promising candidate for vaccination against TB. These results represent an excellent initial step toward development of novel vaccine for TB protection.

Leishmaniasis is one of the major emerging health problems worldwide and Leishmania tropica (L. tropica) is most prevalent in the Middle East due to conflict and environmental factors, and there is no effective prevention strategy available until now. An effective vaccine has not been developed to date. DNA vaccines are considered a promising approach to protect against this infection. In this study, since vacuolar (H+)-ATPase (V-ATPase) enzyme has an essential role in the life cycle of eukaryotes, V-ATPase subunit F gene has been chosen to design DNA vaccine and evaluate its immunogenicity in BALB\c mice.

Genomic DNA was isolated from promastigote culture, synthesized complementary DNA (cDNA) after standardization of Polymerase Chain Reaction (PCR) conditions. The V-ATPase subunit F gene was placed into plasmid PCI. Then, recombinant plasmids were transformed into competent cells. Cloning was confirmed by PCR, restriction enzyme assays, and finally, DNA sequence analysis, after making miniprep from positive colonies and finally the gene was sequenced. BALB/c mice were immunized subcutaneously three times at an interval of two weeks with designed vaccine. BALB\c mice were challenged with 106 promastigotes of L. tropica 7 days post-immunization. IL-12, IFN-γ and IL-4 were quantified by RT-qPCR.

The present study proved the existence of subunit F gene in Syrian strain of L. tropica (LCED Syrian 01) promastigotes genome. Its expression was also proved in these parasites and the gene length was 414 bp.

This study showed that vaccination of BALB\c mice with this gene induced partial protection against Leishmania by reduction of lesion size by 41.9% and parasite burden reduction by 3-log in the dLNs when compared with control group. IFNγ\IL-4 was 1.6 after challenge test, so the immune response consisted of both Th1 and Th2.

Toxoplasma gondii can infect all the warm-blooded vertebrates and cause serious toxoplasmosis. Extracellular signal-regulated kinase 7 in T. gondii (TgERK7) mediated the proliferation of this parasite may be a potential vaccine candidate. Thus, immune responses induced by TgERK7 were investigated in this study using a DNA vaccine strategy.

pVAX/TgERK7 plasmid was constructed and used to immunize BALB/c mice for three times with two-week intervals. The challenge and the investigation of humoral and cellular immune responses were performed at two weeks post the last immunization, and the survival times of the infected mice were daily recorded until all of them were dead.

The innate immune response with higher concentrations of IFN-γ, TNF-α, IL2 and IL12p70 in sera (P < 0.05), and the adaptive immune responses were evoked by the DNA immunizations, including specific antibody, lymphocyte proliferation, and the CD3e+CD4+ and CD3e+CD8a+ T cell-mediated response effects. Interestingly, no significant difference was detected in their survival times among all the experimental groups of mice that were challenged with GT1 tachyzoites or PRU cysts (P>0.05).

The successive immunizations with pVAX/TgERK7 can provoke the innate and adaptive immune responses of BALB/c mice, whereas the DNA vaccine-induced immunological efficacy is not sufficient for complete protection the host against T. gondii infection.

Human colorectal cancer cells overexpress carcinoembryonic antigen (CEA). CEA is a glycoprotein which has shown to be a promising vaccine target for immunotherapy against colorectal cancer.

To design a DNA vaccine harboring CEA antigen and evaluate its effect on inducing immunity against colorectal cancer cells in tumor bearing mice.

In the first step the coding sequence of the CEA was cloned into the pcDNA3.1 vector. The mice were injected with the vaccine construct and the immune responses were monitored during the experiment period. The specific IgG anti-CEA, IFN-γ, IL-2 and IL-4 were measured by ELISA and levels of IFN-γ was detected by ELISpot assay. The lymphocyte proliferation was assessed using a 5-bromo-2-deoxyuridine (BrdU) cell proliferation assay kit.

Immunization of the mice with the CEA plasmid resulted in stimulation of CEAspecific T cell and antibody responses. The serum level of specific IgG antibodies against CEA was increased in immunized mice. Moreover, the injection of CEA plasmid led to the stimulation of T-helper-1 by increase in the secretion of IFN-γ, IL-2 and lymphocyte proliferation response.

As the CEA DNA vaccine displayed encouraging antitumor effects, therefore, we suggest that it can be a potential therapeutic modality for colorectal cancer and is worthy of further investigation.

Toxoplasma gondii is an obligate intracellular protozoan parasite that causes toxoplasmosis in humans and animals. Micronemes (MICs) are effective candidates for DNA vaccine. In this study, we evaluated the immune response of BALB/c mice against MIC3 gene of Toxoplasma gondii and interleukin 12 (IL-12) as DNA vaccine. The MIC3 gene was cloned into the PTZ57R/T vector before sub-cloning in pcDNA3. Recombinant pc-MIC3 was transformed into Escherichia coli (TOP10 strain). The pc-MIC3 plasmid was then transfected into Chinese Hamster Ovary (CHO) cells, and the expression of the MIC3 gene was evaluated by SDS-PAGE and Western blotting. Sixty female BALB/c mice were divided into 6 groups. Each group received 3 intramuscular immunizations on days 0, 21st and 42nd using one of the following stimulants: phosphate-buffered saline, pcDNA3, pCAGGS-IL12, pc-MIC3 (100 µg), pc-MIC3 (50 µg), or combined pCAGGS-IL12 (50 µg) and pc-MIC3 (50 µg). The enzyme-linked immunosorbent assays was applied to evaluate  interferon gamma (IFN-γ) and IL-4 cytokines excretion of lymphocytes stimulated with tachyzoites lysate antigen, as well as the total levels of immunoglobulin G (IgG), IgG2a and IgG1 in immunized mice sera. Our results showed that mice challenged with pc-MIC3 (100 µg) had the highest longevity and quantity of immunoglobulin. Moreover, the highest expression level of IFN-γ was found in mice injected with combined pcMIC3 and pCAGGS-IL12 (P<0.05). The MIC3 gene can be an efficient DNA vaccine candidate against toxoplasmosis. While, the single-gene vaccine can confer partial protection to mice against toxoplasmosis, the multigene vaccine can significantly enhance immune responses.

Acinetobacter baumannii is one the most dangerous opportunistic pathogens in hospitalized infections. This bacterium is resistant to 90% of commercial antibiotics. Therefore, developing new strategies to cure A. baumannii-infections is urgent. The DNA vaccines new approach in which the immunogen can be directly expressed inside the target cells through cloning of immunogen into an expression vector. The outer membrane protein A(OmpA) is one the critical factors in pathogenicity of A. baumannii which has been repeatedly described as a powerful immunogen to trigger the immune responses. As the pure form of the OmpA is insoluble, vaccine delivery is very hard. We previously cloned the ompA gene from A. baumannii into the eukaryotic expression vector pBudCE4.1 and observed that the OmpA protein has been considerably expressed in eukaryotic cell model. In current study, the immunogenic potential of pBudCE4.1-ompA has been evaluated in mice model of experimental. The serum levels of IgM, IgG, IL-2, IL-4, IL-12 and INF-γ were measured by enzyme-linked immunosorbent assay (ELISA) after immunization with ompA-vaccine. The protective efficiency of the designed-DNA vaccine was evaluated following intranasal administration of mice with toxic dose of A. baumannii. Obtained data showed the elevated levels of IgM, IgG, IL-2, IL-4, IL-12 and INF-γ in serum following the vaccine administration and mice who immunized with recombinant vector were survived more than control group. These findings indicate ompA-DNA vaccine is potent to trigger humoral and cellular immunity responses although further experiments are needed.

Tuberculosis caused by Mycobacterium tuberculosis (M. tuberculosis), remains as one of the leading causes of deaths worldwide, with nearly two million death cases annually. BCG (Bacille Calmette-Guerin) continues to be the most widely used vaccine in the world, but the protective immunity differs in different parts of the world. Accordingly, new strategies including DNA vaccines are essentially needed. This study was aimed to design and construct a cloning vector containing mpt64 gene of M. tuberculosis. M. tuberculosis H37Rv was cultured on Lowenstein Jensen medium, and genomic DNA was extracted. The mpt64 gene was amplified by PCR using designed specific primers. After the digestion of mpt64 and pcDNA3.1 (+) by BamHI and EcoRI restriction enzymes, the mpt64 fragment was ligated into the digested vector using T4 DNA ligase enzyme. Then, the recombinant vector was transformed into competent Escherichia coli (E. coli) TOP10 strain. To confirm the colonies of transformed bacteria, antibiotic resistance, colony-PCR, restriction enzyme digestion and DNA sequencing were used. To confirm the clones, colony-PCR using mpt64 specific primers was performed and the fragment of 718 bp was observed by gel electrophoresis. Clones were also verified by restriction enzyme digestion using BamHI and EcoRI restriction enzymes and the 718 bp fragment was observed. Furthermore, results of DNA sequencing showed 100% homology with the mpt64 fragment of H37Rv in GenBank. In this study, the mpt64 fragment was successfully cloned in pcDNA3.1 (+) vector. This construct can be used in future studies as a DNA vaccine in animal models to induce immune system responses. Key words: Mycobacterium tuberculosis, DNA vaccine, cloning vector, mpt64

In recent years attention has been paid to develop effective adjuvant systems for DNA vaccines. Co-formulation of a gene delivery vector with an immunostimulator can enhance therapeutic efficiency of DNA vaccine. To investigate the efficacy of chitosan as a nanodelivery system to enhance antitumor effects of human papilloma virus (HPV)-16 DNA vaccine with IL-12 gene for protection against TC-1 tumor using an animal model. The mice were challenged by subcutaneous injection of TC-1 cells and immunized intramuscularly with DNA vaccine thrice at seven-day intervals. One week after the last immunization, mice were sacrificed and antitumor effects were assessed through measuring lymphocyte proliferation, cytotoxicity, cytokines production, and tumor regression. We found that co-formulation and co-administration of chitosan nanoparticles and IL-12 with HPV-16 E7 DNA vaccine induced higher antitumor effects compared with chitosan or IL-12 alone. E7-specific lymphocyte proliferation index and CTL activity were found to be significantly higher in combination group in comparison to single vaccination with either chitosan or IL-12. Co-formulation of chitosan and IL-12 resulted in higher IFN-γ and IL-4, and decreased IL-10 production. Furthermore, combined vaccination highly inhibited the tumor progression compared with chitosan or IL-12 alone. Chitosan nanoparticle is a promising delivery system for DNA vaccine and IL-12 is an effective genetic adjuvant for the induction of strong antitumor immune response.

Vaccination is one of the most effective means to protect humans and animals against brucellosis. Live attenuated Brucella vaccines are considered effective in animals but they may be potentially infectious to humans, so it is vital to improve the immunoprotective effects and safety of vaccines against Brucella. This study was designed to evaluate the immunogenicity of DNA vaccines encoding B. melitensis outer membrane proteins (Omp25 and Omp31) against B. melitensis Rev1 in a mouse model.
For this propose, Omp25 and Omp31 genes were cloned (individually and together) into the eukaryotic expression vector pcDNA3.1/Hygro (). Expressions of recombinant plasmids were confirmed by SDS-PAGE and Western blot analysis. Six groups of BALB/c mice (seven mice per group) were intramuscularly injected with three recombinant constructs, native pcDNA3.1/Hygro () and phosphate-buffered saline (PBS) as controls and subcutaneous injection of attenuated live vaccine Rev1.
Results indicated that DNA vaccine immunized BALB/c mice had a dominant immunoglobulin G response and elicited a T-cell-proliferative response and induced significant levels of interferon gamma (INF-γ) compared to the control groups.
Collectively, these finding suggested that the pcDNA3.1/Hygro DNA vaccines encoding Omp25 and Omp31 genes and divalent plasmid were able to induce both humoral and cellular immunity, and had the potential to be a vaccine candidate for prevention of B. melitensis infections.

Cutaneous leishmaniasis (CL) is a serious public health problem in many tropical countries. The infection is caused by a protozoan parasite of Leishmania genus transmitted by Phlebotominae sandflies. In the present study, we constructed a eukaryotic expression vector to produce a fusion protein containing LmSTI1 from Leishmania major (L. major) and PpSP42 from Phlebotomus papatasi (Ph. papatasi). In future studies we will test this construct as a DNA vaccine against zoonotic CL.
The nucleotide sequences encoding the LmSTI1 protein and a fragment encoding 79% of PpSP42 were amplified using L. major and Ph. papatasi genomic DNA, respectively. The amplicons were cloned into the pcDNA3.1() eukaryotic expression vector. The recombinant plasmid pcDNA-LmSTI1Pp42 was propagated in Escherichia coli (E. coli) and used to transfect HEK-293T cells. The expressed fusion protein was analyzed by Western blotting using anti-LmSTI1 mouse serum.
Sequences encoding LmSTI1 and partial PpSP42 were cloned into pcDNA3.1(). Production of the recombinant LmSTI1Pp42 fusion protein was confirmed by Western blotting.
An LmSTI1Pp42 fusion protein was expressed HEK-293T cells. This construct may be an effective DNA vaccine against CL.

Leishmaniasis is caused by parasitic protozoa of the genus Leishmania which is an obligate intracellular parasite in the infected host. Individuals who have been recovered from clinical leishmaniasis develop strong immunity against reinfection. DNA vaccines are the new type of vaccines that induce expression of protein eukaryotic cells. DNA vaccines can be stimulated by the cellular and humoral immune responses using one or several genes.
A DNA vaccine containing plasmids encoding the pcLACKꗄ genes of Leishmania major (L. major) (MHRO/IR/75/ER) in the vicinity of IL-12 gene expression was made and then its protective efficacy in comparison with single-gene of LACK was evaluated. Also, BALB/c mice were immunized intramuscularly three times. The humoral and cellular immune responses were evaluated after immunization with pcLACK, pcLACKꗄ툃aIL12, and then challenged with L. major.
Humoral response and IFN-γ values were significantly higher than control groups after immunization with pcLACK, pcLACKꗄ툃aIL12 and challenge with L. major (p≤0.05). IL-4 values were increased in the control groups in such a way that they were remarkably higher than the pcLACK, pcLACKꗄ툃 pCAGGS-IL12 groups (p≤0.05) after immunization and challenge with L. major.
The survival time of the immunized mice with pcLACK, pcLACKꗄ툃 pCAGGS-IL12 groups was higher than the control groups. Then, DNA vaccine of pcLACK appeared to be likely able to induce more protection against infection with L. major in mice. Therefore, cocktail DNA is effective to enhance specific immunity.

The HP0242 plays an important role in physiology of H. pylori in acidic condition.
The aim of this study was cloning and expression of immunogenicity of HP0242 gene of H. pylori.
The whole sequence of the hypothetical gene was amplified with specific primers. The DNA sequence (716 bp) was cloned into E. coli TOP10F by utilizing PEGFP-C1 and PTZ vectors. The protein product in CHO cells was elucidated with the SDS-PAGE technique. Western blot analysis showed that HP0242 expressed by recombinant E. coli had favorable immune-reactivity. Western blot was conducted to assess the immune-reactivity.
Presence of hypothetical gene in the expression PEGFP-C1 vector was confirmed with digestion by sacII and smaI. Finally, the expression of the hypothetical protein in CHO cells was confirmed by SDS-PAGE and thus, can be considered as a DNA vaccine candidate for H. pylori. Western blot analysis showed that HP0242 expressed by recombinant E. coli had a favorable immune-reactivity.
The expressed HP0242 gene showed the possibility that it can be used as a candidate DNA vaccine for H. pylori in the future research.