DNA Vaccine Research Articles

Neoantigen-specific T cell help outperforms non-specific help in multi-antigen DNA vaccination against cancer

CD4+ T-helper antigens are essential components of cancer vaccines, but the relevance of the source of these MHC-class-II-restricted antigens remains underexplored. To compare the effectiveness of tumor-specific versus tumor-unrelated helper antigens, we designed three DNA vaccines for the murine MC-38 colon carcinoma, encoding CD8+ T-cell neoantigens alone (noHELP) or in combination with either ‘universal’ helper antigens (uniHELP) or helper neoantigens (neoHELP). Both types of helped vaccines increased the frequency of vaccine-induced CD8+ T-cells, and particularly uniHELP increased the fraction of KLRG1+ and PD-1low effector cells. However, when mice were subsequently injected with MC-38 cells, only neoHELP vaccination resulted in significantly better tumor control than noHELP. In contrast to uniHELP, neoHELP-induced tumor control was dependent on the presence of CD4+ T-cells, while both vaccines relied on CD8+ T-cells. In line with this, neoHELP variants containing wild-type counterparts of the CD4+ or CD8+ T-cell neoantigens displayed reduced tumor control. These data indicate that optimal personalized cancer vaccines should include MHC-class-II-restricted neoantigens to elicit tumor-specific CD4+ T-cell help.

Synergistic Effect of Maternal Micronutrient Supplementation on ORFV DNA Vaccine Immune Response in a Pregnant Model.

Contagious ecthyma is a contagious zoonotic disease caused by the Orf virus that can infect farm animals and humans, but no vaccine is available for pregnant mothers. Excessive oxidative stress during pregnancy can suppress the vaccine immune response in pregnant mothers; hence, maternal micronutrient supplementation could effectively improve the immune response, health, and oxidative status during pregnancy. In this study, we employed an 8-week-old pregnant rat model to receive a single intramuscular dose of 200µg of ORF DNA vaccine with or without vitamin E and selenium supplementation to evaluate their effect on immune responses (specific IgG and IgG isotypes), oxidative stress, liver enzymes, and blood glucose levels in maternal-neonatal serum and milk secretions. Additionally, antioxidant-related gene expressions were analyzed in the maternal placenta and pups' liver. The results showed that supplementation of vitamin E and selenium with ORF DNA vaccination increased the production of specific antibody and IgG isotypes (IgG1 and IgG2a) and reduced the oxidative stress in neonatal-maternal serum and milk compared to both the control group and those vaccinated without supplementation (p < 0.05). Notably, the ORF DNA vaccine did not cause oxidative stress and hepatic damage. However, combined supplementation of vitamin E and selenium with DNA vaccination significantly decreased serum malondialdehyde (MDA) levels and improved the antioxidant-related enzyme activities of glutathione peroxidase (GPX), superoxide dismutase 1 (SOD1), and selenoprotein P (SELP) in the maternal placenta and liver of pups (p < 0.05). In conclusion, maternal supplementation of vitamin E and selenium enhanced the immune responses of the ORF DNA vaccine by mitigating oxidative stress in pregnant rats and could thus be a promising strategy for better health outcomes for both mothers and neonates.

MRNA Vaccine for Alzheimer's Disease: Pilot Study.

The escalating global healthcare challenge posed by Alzheimer's Disease (AD) and compounded by the lack of effective treatments emphasizes the urgent need for innovative approaches to combat this devastating disease. Currently, passive and active immunotherapies remain the most promising strategy for AD. FDA-approved lecanemab significantly reduces Aβ aggregates from the brains of early AD patients administered biweekly with this humanized monoclonal antibody. Although the clinical benefits noted in these trials have been modest, researchers have emphasized the importance of preventive immunotherapy. Importantly, data from immunotherapy studies have shown that antibody concentrations in the periphery of vaccinated people should be sufficient for targeting Aβ in the CNS. To generate relatively high concentrations of antibodies in vaccinated people at risk of AD, we generated a universal vaccine platform, MultiTEP, and, based on it, developed a DNA vaccine, AV-1959D, targeting pathological Aβ, completed IND enabling studies, and initiated a Phase I clinical trial with early AD volunteers. Our current pilot study combined our advanced MultiTEP technology with a novel mRNA approach to develop an mRNA vaccine encapsulated in lipid-based nanoparticles (LNPs), AV-1959LR. Here, we report our initial findings on the immunogenicity of 1959LR in mice and non-human primates, comparing it with the immunogenicity of its DNA counterpart, AV-1959D.

Peptide-TLR7/8a-Coordinated DNA Vaccines Elicit Enhanced Immune Responses against Infectious Diseases.

DNA vaccines represent an innovative approach for the immunization of diverse diseases. However, their clinical trial outcomes are constrained by suboptimal transfection efficiency and immunogenicity. In this work, we present a universal methodology involving the codelivery of Toll-like receptor 7/8 agonists (TLR7/8a) and antigen gene using TLR7/8a-conjugated peptide-coated poly(β-amino ester) (PBAE) nanoparticles (NPs) to augment delivery efficiency and immune response. Peptide-TLR7/8a-coated PBAE NPs exhibit advantageous biophysical attributes, encompassing diminutive particle dimensions, nearly neutral ζ potential, and stability in the physiological environment. This synergistic approach not only ameliorates the stability of plasmid DNA (pDNA) and gene delivery efficacy but also facilitates subsequent antigen production. Furthermore, under optimal formulation conditions, the TLR7/8a-conjugated peptide coated PBAE NPs exhibit a potent capacity to induce robust immune responses. Collectively, this nanoparticulate gene delivery system demonstrates heightened transfection efficacy, stability, biodegradability, immunostimulatory effect, and low toxicity, making it a promising platform for the clinical advancement of DNA vaccines.

IMMUNE RESPONSE OF MICE TO AFRICAN SWINE FEVER VIRUS DNA VACCINE A224L AND A276R WITH LIPOFECTAMINE,CHOLESTEROL AND POLYMER ENCAPSULATION

A vaccine against African Swine Fever (ASF) is urgently needed to reduce losses for pig farmers throughout the world. The study was aimed to test the immune response of mice to an ASF-DNA vaccine with the A224L and A276R genes with polymer, lipofectamine, and cholesterol adjuvants. Each mouse was vaccinated intramuscularly with 25 μg of plasmid encapsulated with the above adjuvants. Mouse sera were collected at weeks 1, 2, 3 and 4. Antibodies against A224L and A276R were detected by ELISA test using synthetic peptides as antigens. Optical density (OD) values were analysed statistically using the Analysis of Variance test with the SPSS Version 25. The results showed that the OD values of the serum of mice given the ASF-A224L and A276R DNA vaccines with polymer adjuvants (0.149), lipofectamine (0.080), and cholesterol (0.058), as well as control mice (0.020) differed significantly (p= 0.000), while the time of serum collection had no significant effect (p=0.517). The conclusion is that the OD values of mice sera after DNA-ASF-A224L and A276R encapsulated with polymer, lipofectamine and cholesterol were statistically significant, while sampling time did not show any statistically difference. Further studies are needed to improve the adjuvant mixing protocol with larger quantities of plasmids.Keywords:mice; DNA vaccine; ASF; polymer; ELISA

SWIFT clustering analysis of intracellular cytokine staining flow cytometry data of the HVTN 105 vaccine trial reveals high frequencies of HIV-specific CD4+ T cell responses and associations with humoral responses.

The HVTN 105 vaccine clinical trial tested four combinations of two immunogens - the DNA vaccine DNA-HIV-PT123, and the protein vaccine AIDSVAX B/E. All combinations induced substantial antibody and CD4+ T cell responses in many participants. We have now re-examined the intracellular cytokine staining flow cytometry data using the high-resolution SWIFT clustering algorithm, which is very effective for enumerating rare populations such as antigen-responsive T cells, and also determined correlations between the antibody and T cell responses. Flow cytometry samples across all the analysis batches were registered using the swiftReg registration tool, which reduces batch variation without compromising biological variation. Registered data were clustered using the SWIFT algorithm, and cluster template competition was used to identify clusters of antigen-responsive T cells and to separate these from constitutive cytokine producing cell clusters. Registration strongly reduced batch variation among batches analyzed across several months. This in-depth clustering analysis identified a greater proportion of responders than the original analysis. A subset of antigen-responsive clusters producing IL-21 was identified. The cytokine patterns in each vaccine group were related to the type of vaccine - protein antigens tended to induce more cells producing IL-2 but not IFN-γ, whereas DNA vaccines tended to induce more IL-2+ IFN-γ+ CD4 T cells. Several significant correlations were identified between specific antibody responses and antigen-responsive T cell clusters. The best correlations were not necessarily observed with the strongest antibody or T cell responses. In the complex HVTN105 dataset, alternative analysis methods increased sensitivity of the detection of antigen-specific T cells; increased the number of identified vaccine responders; identified a small IL-21-producing T cell population; and demonstrated significant correlations between specific T cell populations and serum antibody responses. Multiple analysis strategies may be valuable for extracting the most information from large, complex studies.

Sparsely PEGylated poly(beta-amino ester) polyplexes enhance antigen specific T-cell response of a bivalent SARS-CoV-2 DNA vaccine

DNA technology has emerged as a promising route to accelerated manufacture of sequence agnostic vaccines. For activity, DNA vaccines must be protected and delivered to the correct antigen presenting cells. However, the physicochemical properties of the vector must be carefully tuned to enhance interaction with immune cells and generate sufficient immune response for disease protection. In this study, we have engineered a range of polymer-based nanocarriers based on the poly(beta-amino ester) (PBAE) polycation platform to investigate the role that surface poly(ethylene glycol) (PEG) density has on pDNA encapsulation, formulation properties and gene transfectability both in vitro and in vivo. We achieved this by synthesising a non-PEGylated and PEGylated PBAE and produced formulations containing these PBAEs, and mixed polyplexes to tune surface PEG density. All polymers and co-formulations produced small polyplex nanoparticles with almost complete encapsulation of the cargo in all cases. Despite high gene transfection in HEK293T cells, only the fully PEGylated and mixed formulations displayed significantly higher expression of the reporter gene than the negative control in dendritic cells. Further in vivo studies with a bivalent SARS-CoV-2 pDNA vaccine revealed that only the mixed formulation led to strong antigen specific T-cell responses, however this did not translate into the presence of serum antibodies indicating the need for further studies into improving immunisation with polymer delivery systems.

Active immunization with inhibin DNA vaccine promotes spermatogenesis and testicular development in rats

ABSTRACT The objective of the present study was to investigate the potential role of immunization against INH on testicular development, serum reproductive hormone (FSH, LH and T) concentrations, testicular biochemical indexes (GGT, ALP, ACP, LDH, α-neutral glucosidase and carnitine) and testicular cell apoptosis in rats. Forty healthy male rats were randomly divided into four groups (n = 10 per group), and respectively immunized with 0.5 mL of C500/pVAX-asd-IS-L (108 CFU/ mL), C500/pVAX-asd-IS-M (109 CFU/ mL), C500/pVAX-asd-IS-H (1010 CFU/ mL) or C500 (1010 CFU/ mL) (thrice with an interval of 2 weeks). P/N values increased after vaccination and differed (p < 0.05) at 1 week and sharply increased at 2 weeks following the booster vaccination (p < 0.01); P/N values indicated that the immune response was induced and production of anti-INH antibodies in rats; Immunization of INH vaccines enhanced serum concentrations of T and FSH, while reduced LH concentrations (p < 0.05); The testis weight, volume, testis coefficient, epididymal weight, sperm count in the epididymis, and the sperm deformity results indicated that INH gene vaccine immunization could promote testicular development and enhance sperm production rate in rats. After immunization of INH gene vaccines, GGT activity was markedly increased, but ALP, LDH and α-neutral glucosidase activities were observably reduced (p < 0.05). Furthermore, flow cytometry results demonstrated that the apoptosis rate of the testicular cells was extremely increased in the C500/pVAX-asd-IS-M group (p < 0.01). These findings illustrate a functional cross-link between FSH, T, LH and spermatogenic markers via inhibin to maintain spermatogenesis. INH immunization may have a positive effect on spermatogenesis and testicular development in male rats.

PI3Kγ inhibition combined with DNA vaccination unleashes a B-cell-dependent antitumor immunity that hampers pancreatic cancer

Phosphoinositide-3-kinase γ (PI3Kγ) plays a critical role in pancreatic ductal adenocarcinoma (PDA) by driving the recruitment of myeloid-derived suppressor cells (MDSC) into tumor tissues, leading to tumor growth and metastasis. MDSC also impair the efficacy of immunotherapy. In this study we verify the hypothesis that MDSC targeting, via PI3Kγ inhibition, synergizes with α-enolase (ENO1) DNA vaccination in counteracting tumor growth.Mice that received ENO1 vaccination followed by PI3Kγ inhibition had significantly smaller tumors compared to those treated with ENO1 alone or the control group, and correlated with i) increased circulating anti-ENO1 specific IgG and IFNγ secretion by T cells, ii) increased tumor infiltration of CD8+ T cells and M1-like macrophages, as well as up-modulation of T cell activation and M1-like related transcripts, iii) decreased infiltration of Treg FoxP3+ T cells, endothelial cells and pericytes, and down-modulation of the stromal compartment and T cell exhaustion gene transcription, iv) reduction of mature and neo-formed vessels, v) increased follicular helper T cell activation and vi) increased “antigen spreading”, as many other tumor-associated antigens were recognized by IgG2c “cytotoxic” antibodies. PDA mouse models genetically devoid of PI3Kγ showed an increased survival and a pattern of transcripts in the tumor area similar to that of pharmacologically-inhibited PI3Kγ-proficient mice. Notably, tumor reduction was abrogated in ENO1 + PI3Kγ inhibition-treated mice in which B cells were depleted.These data highlight a novel role of PI3Kγ in B cell-dependent immunity, suggesting that PI3Kγ depletion strengthens the anti-tumor response elicited by the ENO1 DNA vaccine.

WITHDRAWN: COVID-19: Post infection implications in different age groups, mechanism, diagnosis, effective prevention, treatment, and recommendations

SARS-CoV-2 is a highly contagious pathogen that predominantly caused the COVID-19 pandemic. The persistent effects of COVID-19 are defined as an inflammatory or host response to the virus that begins four weeks after initial infection and persists for an undetermined length of time. Chronic effects are more harmful than acute ones thus, this review explored the long-term effects of the virus on various human organs, including the pulmonary, cardiovascular, and neurological, reproductive, gastrointestinal, musculoskeletal, endocrine, and lymphoid systems and found that SARS-CoV-2 adversely affects these organs of older adults. Regarding diagnosis, the RT-PCR is a gold standard method of diagnosing COVID-19; however, it requires specialized equipment and personnel for performing assays and a long time for results production. Therefore, to overcome these limitations, artificial intelligence employed in imaging and microfluidics technologies is the most promising in diagnosing COVID-19. Pharmacological and non-pharmacological strategies are the most effective treatment for reducing the persistent impacts of COVID-19 by providing immunity to post-COVID-19 patients by reducing cytokine release syndrome, improving the T cell response, and increasing the circulation of activated natural killer and CD8 T cells in blood and tissues, which ultimately reduces fever, nausea, fatigue, and muscle weakness and pain. Vaccines such as inactivated viral, live attenuated viral, protein subunit, viral vectored, mRNA, DNA, or nanoparticle vaccines significantly reduce the adverse long-term virus effects in post-COVID-19 patients; however, no vaccine was reported to provide lifetime protection against COVID-19; consequently, protective measures such as physical separation, mask use, and hand cleansing are promising strategies. This review provides a comprehensive knowledge of the persistent effects of COVID-19 on people of varying ages, as well as diagnosis, treatment, vaccination, and future preventative measures against the spread of SARS-CoV-2.

Current Status of Vaccines for Porcine Reproductive and Respiratory Syndrome: Interferon Response, Immunological Overview, and Future Prospects.

Porcine reproductive and respiratory syndrome (PRRS) remains a formidable challenge for the global pig industry. Caused by PRRS virus (PRRSV), this disease primarily affects porcine reproductive and respiratory systems, undermining effective host interferon and other immune responses, resulting in vaccine ineffectiveness. In the absence of specific antiviral treatments for PRRSV, vaccines play a crucial role in managing the disease. The current market features a range of vaccine technologies, including live, inactivated, subunit, DNA, and vector vaccines, but only modified live virus (MLV) and killed virus (KV) vaccines are commercially available for PRRS control. Live vaccines are promoted for their enhanced protective effectiveness, although their ability to provide cross-protection is modest. On the other hand, inactivated vaccines are emphasized for their safety profile but are limited in their protective efficacy. This review updates the current knowledge on PRRS vaccines' interactions with the host interferon system, and other immunological aspects, to assess their current status and evaluate advents in PRRSV vaccine development. It presents the strengths and weaknesses of both live attenuated and inactivated vaccines in the prevention and management of PRRS, aiming to inspire the development of innovative strategies and technologies for the next generation of PRRS vaccines.

Phase II trial assessing safety, efficacy and immune correlates of heterologous prime-boost with pBI-11 (IM) and TA-HPV (IM) plus pembrolizumab for advanced, PD-L1 CPS≥1, hrHPV+ oropharyngeal cancer.

TPS6118 Background: HPV-related OPSCC occurs in younger patients, has a significantly better prognosis, and is most often caused by HPV subtype 16. There is a 90% overall survival for HPV+/p16+ OPSCC (40% for HPV-/p16- OPSCC), which can be cured with multimodality care. For patients with R/M disease, treatment with pembrolizumab (P) +/- chemotherapy is palliative, with a median OS of approximately 12 months for patients with PD-L1 combined positive score (cps) &gt;1 treated with P alone. Heterologous prime boost with DNA priming followed by vaccinia-based boosting against HPV16 viral antigens will be studied using pBI-11 [(DNA vaccine pNGVL4a-SigE7 (detox)/HSP70, HPV16 E7(detox)/ HPV18 E7(detox), HPV16 E6(detox), and HPV18 E6(detox)] followed by TA-HPV (recombinant vaccinia-human papillomavirus (denoted TA-HPV) derived from the Wyeth strain of vaccinia which carries modified E6 and E7 genes from HPV types 16 and 18). This study is approved by the Vanderbilt University IRB and is open accrual (NCT NCT05799144). Methods: Patients with R/M, HPV positive OPSCC without prior therapy for R/M disease, without contraindications to immunotherapy and with a PD-L1 cps &gt; 1 will be screened. There is a 6 patient safety run-in. Treatment with pBI-11 vaccine (2 IM injections on weeks 1 and 4) plus one IM administration of TA-HPV on week 7 will be given in combination with P IV on weeks 1, 4, and 7). Following restaging, all patients will continue (including those with PD) with 3 more cycles of P followed by restaging. The primary clinical outcome is RR to addition of vaccine in the 50% of predicted P non-responders (NR) who proceed to Part II (ie conversion to responders). All responders will continue to receive P until progression. Approximately 54 patients with be enrolled. Two research tumor biopsies and blood draws will be obtained pre- and on treatment (week7-9). Tumor tissue cores will be utilized for immunohistochemical and molecular tests (e.g., expression of immune cell and viral markers, TCR sequencing and total transcripts). Blood with be tested for HPV16/18 E6, E7 antibodies and vaccinia virus neutralizing assays; proliferative responses of peripheral blood lymphocytes to stimulation by HPV16/18 E6 and E7; HPV16/18 E6- and E7-Specific T cells; and HPV DNA in plasma. Data from the 1st four patients enrolled will be presented. Clinical trial information: NCT05799144 .

A Novel Recombinant Modified Vaccinia Ankara Virus expressing Interleukin-13 Receptor α2 Antigen for Potential Cancer Immunotherapy.

Genetically altered recombinant poxviruses hold great therapeutic promise in animal models of cancer. Poxviruses can induce effective cellmediated immune responses against tumor-associated antigens. Preventive and therapeutic vaccination with a DNA vaccine expressing IL-13Rα2 can mediate partial regression of established tumors in vivo, indicating that host immune responses against IL-13Rα2 need further augmentation. The aim of the study is developing a recombinant modified vaccinia Ankara (MVA) expressing IL-13Rα2 (rMVA-IL13Rα2) virus and study in vitro infectivity and efficacy against IL-13Rα2 positive cell lines. We constructed a recombinant MVA expressing IL-13Rα2 and a green fluorescent protein (GFP) reporter gene. Purified virus titration by infection of target cells and immunostaining using anti-vaccinia and anti-IL-13Rα2 antibodies was used to confirm the identity and purity of the rMVA-IL13Rα2. Western Blot analysis confirmed the presence of IL-13Rα2 protein (~52 kDa). Flow cytometric analysis of IL-13Rα2 negative T98G glioma cells when infected with rMVA-IL13Rα2 virus demonstrated cell-surface expression of IL-13Rα2, indicating the infectivity of the recombinant virus. Incubation of T98G-IL13Rα2 cells with varying concentrations (0.1-100 ng/ml) of interleukin-13 fused to truncated Pseudomonas exotoxin (IL13-PE) resulted in depletion of GFP+ fluorescence in T98G-IL13Rα2 cells. IL13-PE (10-1000 ng/ml) at higher concentrations also inhibited the protein synthesis in T98G-IL13Rα2 cells compared to cells infected with the control pLW44-MVA virus. IL13- PE treatment of rMVA-IL13Rα2 infected chicken embryonic fibroblast and DF-1 cell line reduced virus titer compared to untreated cells. rMVA-IL13Rα2 virus can successfully infect mammalian cells to express IL-13Rα2 in a biologically active form on the surface of infected cells. To evaluate the efficacy of rMVA-IL13Rα2, immunization studies are planned in murine tumor models.

A DNA plasmid melanoma cancer vaccine, SCIB1, combined with nivolumab + ipilimumab in patients with advanced unresectable melanoma: Efficacy and safety results from the open-label phase 2 SCOPE trial.

9535 Background: Targeting melanoma by T cells drives anti-tumor responses. We previously showed that SCIB1, a DNA vaccine incorporating T cell epitopes from TRP-2/gp100 into an antibody framework to allow Fc targeting of activated dendritic cells, was successful as monotherapy in a Phase 1/2 trial in Stage III/IV melanoma patients. Disease control was achieved in 60% of cases of unresectable melanoma. In addition, 88% of 20 Stage III/IV patients treated with SCIB1 who had had a previous successful tumor resection, were disease free for 5 years. 1st line combination treatment with nivolumab and ipilimumab in advanced melanoma has a reported ORR of 50%. The current SCOPE trial tests the hypothesis that patients with unresectable melanoma may improve response rate when SCIB1 is given with checkpoint inhibitors (CPI). Methods: Previously untreated patients with unresectable Stage III/IV melanoma were treated with nivolumab with ipilimumab and SCIB1 (8 mg) i.m. using needle-free injections at a fixed dosing schedule for a total of 10 doses over 24 months. The CPI therapy was administered in accordance with respective SmPC. ORR, as measured by RECIST 1.1 in the intention-to-treat population, is the primary endpoint. The study is designed using Simon's two stage methodology with 80% power when the ORR of no interest is 50% and the true ORR is 70% with an overall type I error of 5%. In the 1st stage, 15 patients have been enrolled and as there were more than 8 clinical responses (ORR [CR or PR]) within 25 weeks of the 1st SCIB1 dose. Having passed Simon Stage 1, further recruitment continues. The null hypothesis will be rejected if 27 or more responses are observed in 43 patients. Results: To date, 23 patients have received the combination of SCIB1 with nivolumab and ipilimumab. At study entry, all patients were Stage IV. 13 patients have reached the first imaging timepoint at 13 weeks, the objective response rate is 11/13 (85%). 11/11 responses were confirmed in a subsequent scan (1 CR and 10 PRs); DCR 12/13 (92%) and 1 PD. Patients showed a 40-100% reduction in tumor volume at 13 and/or 25 weeks. Most of the SCIB1 adverse reactions were Grade 1/2 injection site related or headaches. 3 patients reported Grade 3 events (rash, neutropenia and raised GGT) all related to the CPIs. Observed toxicity frequency and intensity was in line with reported figures from ipilimumab/nivolumab therapy. Serious adverse reactions to date have all been related only to the CPIs. Conclusions: SCIB1 given with nivolumab and ipilimumab, as 1st line treatment in unresectable melanoma, improved the ORR to 85% without an increase in clinically meaningful adverse events. These results, if confirmed in the larger ongoing patient cohort, provide confidence in initiating a randomized registration program in unresectable melanoma patients with this novel DNA plasmid technology. Clinical trial information: NCT04079166 .

Vaccine approaches and treatment aspects against Crimean Congo hemorrhagic fever.

Crimean-Congo hemorrhagic fever [CCHF] is a severe infectious viral disease caused by a tick borne virus which can lead to fatal hemorrhagic disease in humans. It has been reported from some continents including Africa, Asia and Europe. Virus is transmitted to human mainly through tick bite, whose acquire infection from reservoirs wild and domesticated mammalians and ostriches. Currently no approved vaccine or drug is available for CCHF and prevention is mainly based on biosecurity measures. Ribavirin is the only approved drug that has been used in some countries to treat human disease, however some new studies did not prove the Ribavirin efficacy. Different strategies to design effective vaccines, have been conducted through years, from inactivated virus to nucleotide-based ones including DNA and mRNA vaccines. In this study we review of pioneering vaccine candidate platforms.

Protective Efficacy of a Novel DNA Vaccine with a CL264 Molecular Adjuvant against Toxoplasma gondii in a Murine Model.

Toxoplasmosis is a significant global zoonosis with devastating impacts, and an effective vaccine against toxoplasmosis for humans has not yet been developed. In this study, we designed and formulated a novel DNA vaccine encoding the inhibitor of STAT1 transcriptional activity (IST) of T. gondii utilizing the eukaryotic expression vector pEGFP-N1 for the first time, with CL264 being a molecular adjuvant. Following intramuscular injection of the vaccine into mice, the levels of antibodies and cytokines were assessed to evaluate the immune response. Additionally, mice were challenged with highly virulent RH-strain tachyzoites of T. gondii, and their survival time was observed. The results show that the levels of IgG in serum, the ratio of IgG2a/IgG1 and the levels of IFN-γ in splenocytes of mice were significantly higher in the pEGFP-TgIST group and the pEGFP-TgIST + CL264 group than in the control group. In addition, the proportion of CD4+/CD8+ T cells was higher in mice immunized with either the pEGFP-TgIST group (p < 0.001) or the pEGFP-TgIST + CL264 group (p < 0.05) compared to the three control groups. Notably, TgIST-immunized mice exhibited prolonged survival times after T. gondii RH strain infection (p < 0.05). Our findings collectively demonstrate that the TgIST DNA vaccine elicits a significant humoral and cellular immune response and offers partial protection against acute T. gondii infection in the immunized mice, which suggests that TgIST holds potential as a candidate for further development as a DNA vaccine.

A Comprehensive Review of Our Understanding and Challenges of Viral Vaccines against Swine Pathogens.

Pig farming has become a strategically significant and economically important industry across the globe. It is also a potentially vulnerable sector due to challenges posed by transboundary diseases in which viral infections are at the forefront. Among the porcine viral diseases, African swine fever, classical swine fever, foot and mouth disease, porcine reproductive and respiratory syndrome, pseudorabies, swine influenza, and transmissible gastroenteritis are some of the diseases that cause substantial economic losses in the pig industry. It is a well-established fact that vaccination is undoubtedly the most effective strategy to control viral infections in animals. From the period of Jenner and Pasteur to the recent new-generation technology era, the development of vaccines has contributed significantly to reducing the burden of viral infections on animals and humans. Inactivated and modified live viral vaccines provide partial protection against key pathogens. However, there is a need to improve these vaccines to address emerging infections more comprehensively and ensure their safety. The recent reports on new-generation vaccines against swine viruses like DNA, viral-vector-based replicon, chimeric, peptide, plant-made, virus-like particle, and nanoparticle-based vaccines are very encouraging. The current review gathers comprehensive information on the available vaccines and the future perspectives on porcine viral vaccines.

Design and evaluation of a multi-epitope DNA vaccine against HPV16

ABSTRACT Cervical cancer, among the deadliest cancers affecting women globally, primarily arises from persistent infection with high-risk human papillomavirus (HPV). To effectively combat persistent infection and prevent the progression of precancerous lesions into malignancy, a therapeutic HPV vaccine is under development. This study utilized an immunoinformatics approach to predict epitopes of cytotoxic T lymphocytes (CTLs) and helper T lymphocytes (HTLs) using the E6 and E7 oncoproteins of the HPV16 strain as target antigens. Subsequently, through meticulous selection of T-cell epitopes and other necessary elements, a multi-epitope vaccine was constructed, exhibiting good immunogenic, physicochemical, and structural characteristics. Furthermore, in silico simulations showed that the vaccine not only interacted well with toll-like receptors (TLR2/TLR3/TLR4), but also induced a strong innate and adaptive immune response characterized by elevated Th1-type cytokines, such as interferon-gamma (IFN-γ) and interleukin-2 (IL2). Additionally, our study investigated the effects of different immunization intervals on immune responses, aiming to optimize a time-efficient immunization program. In animal model experiments, the vaccine exhibited robust immunogenic, therapeutic, and prophylactic effects. Administered thrice, it consistently induced the expansion of specific CD4 and CD8 T cells, resulting in substantial cytokines release and increased proliferation of memory T cell subsets in splenic cells. Overall, our findings support the potential of this multi-epitope vaccine in combating HPV16 infection and signify its candidacy for future HPV vaccine development.

Suitable Promoter for DNA Vaccination Using a pDNA Ternary Complex.

In this study, we evaluated the effect of several promoters on the transfection activity and immune-induction efficiency of a plasmid DNA (pDNA)/polyethylenimine/γ-polyglutamic acid complex (pDNA ternary complex). Model pDNAs encoding firefly luciferase (Luc) were constructed with several promoters, such as simian virus 40 (SV40), eukaryotic elongation factor 1 alpha (EF1), cytomegalovirus (CMV), and chicken beta actin hybrid (CBh) (pSV40-Luc, pEF1-Luc, pCMV-Luc, and pCBh-Luc, respectively). Four types of pDNA ternary complexes, each with approximately 145-nm particle size and -30-mV ζ-potential, were stably constructed. The pDNA ternary complex containing pSV40-Luc showed low gene expression, but the other complexes containing pEF1-Luc, pCMV-Luc, and pCBh-Luc showed high gene expression in DC2.4 cells and spleen after intravenous administration. After immunization using various pDNA encoding ovalbumin (OVA) such as pEF1-OVA, pCMV-OVA, and pCBh-OVA, only the pDNA ternary complex containing pCBh-OVA showed significant anti-OVA immunoglobulin G (IgG) induction. In conclusion, our results showed that the CBh promoter is potentially suitable for use in pDNA ternary complex-based DNA vaccination.

Cytomegalovirus UL44 protein induces a potent T-cell immune response in mice

Due to the severity of CMV infection in immunocompromised individuals the development of a vaccine has been declared a priority. However, despite the efforts made there is no yet a vaccine available for clinical use. We designed an approach to identify new CMV antigens able to inducing a broad immune response that could be used in future vaccine formulations.We have used serum samples from 28 kidney transplant recipients, with a previously acquired CMV-specific immune response to identify viral proteins that were recognized by the antibodies present in the patient serum samples by Western blot. A band of approximately 45 kDa, identified as UL44, was detected by most serum samples. UL44 immunogenicity was tested in BALB/c mice that received three doses of the UL44-pcDNA DNA vaccine. UL44 elicited both, a strong antibody response and CMV-specific cellular response. Using bioinformatic analysis we demonstrated that UL44 is a highly conserved protein and contains epitopes that are able to activate CD8 lymphocytes of the most common HLA alleles in the world population. We constructed a UL44 ORF deletion mutant virus that produced no viral progeny, suggesting that UL44 is an essential viral protein. In addition, other authors have demonstrated that UL44 is one of the most abundant viral proteins after infection and have suggested an essential role of UL44 in viral replication. Altogether, our data suggests that UL44 is a potent antigen, and favored by its abundance, it may be a good candidate to include in a vaccine formulation.