Unlocking PD-1 antibody resistance: The MUC1 DNA vaccine augments CD8+ T cell infiltration and attenuates tumour suppression.

In light of increasing resistance to PD1 antibody therapy among certain patient populations, there is a critical need for in-depth research. Our study assesses the synergistic effects of a MUC1 DNA vaccine and PD1 antibody for surmounting PD1 resistance, employing a murine CT26/MUC1 colon carcinoma model for this purpose. When given as a standalone treatment, PD1 antibodies showed no impact on tumour growth. Additionally, there was no change observed in the intra-tumoural T-cell ratios or in the functionality of T-cells. In contrast, the sole administration of a MUC1 DNA vaccine markedly boosted the cytotoxicity of CD8+ T cells by elevating IFN-γ and granzyme B production. Our compelling evidence highlights that combination therapy more effectively inhibited tumour growth and prolonged survival compared to either monotherapy, thus mitigating the limitations intrinsic to single-agent therapies. This enhanced efficacy was driven by a significant alteration in the tumour microenvironment, skewing it towards pro-immunogenic conditions. This assertion is backed by a raised CD8+/CD4+ T-cell ratio and a decrease in immunosuppressive MDSC and Treg cell populations. On the mechanistic front, the synergistic therapy amplified expression levels of CXCL13 in tumours, subsequently facilitating T-cell ingress into the tumour setting. In summary, our findings advocate for integrated therapy as a potent mechanism for surmounting PD1 antibody resistance, capitalizing on improved T-cell functionality and infiltration. This investigation affords critical perspectives on enhancing anti-tumour immunity through the application of innovative therapeutic strategies.

Traditional Chinese medicine bufalin inhibits infectious hematopoietic necrosis virus infection in vitro and in vivo.

Infectious hematopoietic necrosis virus (IHNV) causes infectious hematopoietic necrosis and severe economic losses to salmon and trout aquaculture worldwide. Currently, the only commercial vaccine against IHNV is a DNA vaccine with some biosafety concerns. Hence, more effective vaccines and antiviral drugs are needed to prevent IHNV infection. In this study, 1,483 compounds were screened from a traditional Chinese medicine monomer library, and bufalin showed potential antiviral activity against IHNV. The 50% cytotoxic concentration of bufalin was >20 µM, and the 50% inhibitory concentration was 0.1223 µΜ against IHNV. Bufalin showed the inhibition of diverse IHNV strains in vitro, which confirmed that it had an inhibitory effect against all IHNV strains, rather than random activity against a single strain. The bufalin-mediated block of IHNV infection occurred at the viral attachment and RNA replication stages, but not internalization. Bufalin also inhibited IHNV infection in vivo and significantly increased the survival of rainbow trout compared with the mock drug-treated group, and this was confirmed by in vivo viral load monitoring. Our data showed that the anti-IHNV activity of bufalin was proportional to extracellular Na+ concentration and inversely proportional to extracellular K+ concentration, and bufalin may inhibit IHNV infection by targeting Na+/K+-ATPase. The in vitro and in vivo studies showed that bufalin significantly inhibited IHNV infection and may be a promising candidate drug against the disease in rainbow trout. IMPORTANCE: Infectious hematopoietic necrosis virus (IHNV) is the pathogen of infectious hematopoietic necrosis (IHN) which outbreak often causes huge economic losses and hampers the healthy development of salmon and trout farming. Currently, there is only one approved DNA vaccine for IHN worldwide, but it faces some biosafety problems. Hence, more effective vaccines and antiviral drugs are needed to prevent IHNV infection. In this study, we report that bufalin, a traditional Chinese medicine, shows potential antiviral activity against IHNV both in vitro and in vivo. The bufalin-mediated block of IHNV infection occurred at the viral attachment and RNA replication stages, but not internalization, and bufalin inhibited IHNV infection by targeting Na+/K+-ATPase. The in vitro and in vivo studies showed that bufalin significantly inhibited IHNV infection and may be a promising candidate drug against the disease in rainbow trout.

[Adjuvant effect of dispersed fullerene C60 on the immune response to constructs harboring amino acid and nucleotide sequences of hepatitis C virus nonstructural NS5B protein].

INTRODUCTION: A vaccine against hepatitis C has not yet been developed. Recombinant proteins and plasmids encoding hepatitis C virus (HCV) proteins, the components of candidate vaccines, induce a weak immune response and require the use of adjuvants. The aim of the work was to study the adjuvant action of an aqueous solution of fullerene C60 during immunization of mice with HCV recombinant protein NS5B (rNS5B) that is an RNA-dependent RNA polymerase, or with NS5B-encoding pcNS5B plasmid. MATERIALS AND METHODS: An aqueous solution of dispersed fullerene (dnC60) was obtained by ultrafiltration. C57BL/6 mice were immunized with rNS5B subcutaneously, pcNS5B intramuscularly mixed with different doses of dnC60 three times, then the humoral and cellular response to HCV was evaluated. RESULTS: Mice immunization with rNS5B in a mixture with dnC60 at doses of 250 g/mouse significantly induced humoral response: a dose-dependent increase in IgG1 antibody titers was 720 times higher than in the absence of fullerene. There was no increase in the cellular response to rNS5B when administered with dnC60. The humoral response to DNA immunization was weak in mice of all groups receiving pcNS5B. The cellular response was suppressed when the plasmid was injected in a mixture with dnC60. CONCLUSIONS: Dispersed fullerene dnC60 is a promising adjuvant for increasing the immunostimulating activity of weakly immunogenic proteins including surface and other HCV proteins, important for a protective response. Further research is needed to enhance the ability of dnC60 to boost the cellular immune response to the components of the candidate vaccine.

Enhancement of immune responses by vaccine potential of three antigens, including ROP18, MIC4, and SAG1 against acute toxoplasmosis in mice.

Toxoplasma gondii (T. gondii) causes considerable financial losses in the livestock industry and can present serious threats to pregnant women, as well as immunocompromised patients. Therefore, it is required to design and produce an efficient vaccine for controlling toxoplasmosis. The present study aimed to evaluate the protective immunity induced by RMS protein (ROP18, MIC4, and SAG1) with Freund adjuvant, calcium phosphate nanoparticles (CaPNs), and chitosan nanoparticles (CNs) in BALB/c mice. The RMS protein was expressed in Escherichia coli (E. coli) and purified using a HisTrap HP column. Thereafter, cellular and humoral immunity was assessed by injecting RMS protein on days 0, 21, and 35 into four groups [RMS, RMS-chitosan nanoparticles (RMS-CNs), RMS-calcium phosphate nanoparticles (RMS-CaPNs), and RMS-Freund]. Phosphate buffered saline (PBS), CNs, CaPNs, and Freund served as the four control groups. The results displayed that vaccination with RMS protein and adjuvants significantly elicited the levels of specific IgG antibodies and cytokines against toxoplasmosis. There were high levels of total IgG, IgG2a, and IFN-γ in vaccinated mice, compared to those in the control groups, especially in the RMS-Freund, indicating a Th-1 type response. The vaccinated and control mice were challenged intraperitoneally with 1 × 103 tachyzoites of the T. gondii RH strain four weeks after the last injection, and in RMS-Freund and RMS-CaPNs groups, the highest increase in survival time was observed (15 days). The RMS can significantly increase Th1 and Th2 responses; moreover, multi-epitope vaccines with adjuvants can be a promising strategy for the production of a vaccine against toxoplasmosis.

Breast cancer vaccines: New insights into immunomodulatory and nano-therapeutic approaches.

Breast cancer (BC) is known to be a highly heterogeneous disease that is clinically subdivided into four primary molecular subtypes, each having distinct morphology and clinical implications. These subtypes are principally defined by hormone receptors and other proteins involved (or not involved) in BC development. BC therapeutic vaccines [including peptide-based vaccines, protein-based vaccines, nucleic acid-based vaccines (DNA/RNA vaccines), bacterial/viral-based vaccines, and different immune cell-based vaccines] have emerged as an appealing class of cancer immunotherapeutics when used alone or combined with other immunotherapies. Employing the immune system to eliminate BC cells is a novel therapeutic modality. The benefit of active immunotherapies is that they develop protection against neoplastic tissue and readjust the immune system to an anti-tumor monitoring state. Such immunovaccines have not yet shown effectiveness for BC treatment in clinical trials. In recent years, nanomedicines have opened new windows to increase the effectiveness of vaccinations to treat BC. In this context, some nanoplatforms have been designed to efficiently deliver molecular, cellular, or subcellular vaccines to BC cells, increasing the efficacy and persistence of anti-tumor immunity while minimizing undesirable side effects. Immunostimulatory nano-adjuvants, liposomal-based vaccines, polymeric vaccines, virus-like particles, lipid/calcium/phosphate nanoparticles, chitosan-derived nanostructures, porous silicon microparticles, and selenium nanoparticles are among the newly designed nanostructures that have been used to facilitate antigen internalization and presentation by antigen-presenting cells, increase antigen stability, enhance vaccine antigenicity and remedial effectivity, promote antigen escape from the endosome, improve cytotoxic T lymphocyte responses, and produce humoral immune responses in BC cells. Here, we summarized the existing subtypes of BC and shed light on immunomodulatory and nano-therapeutic strategies for BC vaccination. Finally, we reviewed ongoing clinical trials on BC vaccination and highlighted near-term opportunities for moving forward.

Novel suction-based in vivo cutaneous DNA transfection platform.

This work reports a suction-based cutaneous delivery method for in vivo DNA transfection. Following intradermal Mantoux injection of plasmid DNA in a rat model, a moderate negative pressure is applied to the injection site, a technique similar to Chinese báguàn and Middle Eastern hijama cupping therapies. Strong GFP expression was demonstrated with pEGFP-N1 plasmids where fluorescence was observed as early as 1 hour after dosing. Modeling indicates a strong correlation between focal strain/stress and expression patterns. The absence of visible and/or histological tissue injury contrasts with current in vivo transfection systems such as electroporation. Specific utility was demonstrated with a synthetic SARS-CoV-2 DNA vaccine, which generated host humoral immune response in rats with notable antibody production. This method enables an easy-to-use, cost-effective, and highly scalable platform for both laboratorial transfection needs and clinical applications for nucleic acid­based therapeutics and vaccines.

ATP stabilised and sensitised calcium phosphate nanoparticles as effective adjuvants for a DNA vaccine against cancer.

Cancer vaccines based on DNA encoding oncogenes have shown great potential in preclinical studies. However, the efficacy of DNA vaccines is limited by their weak immunogenicity because of low cellular internalisation and insufficient activation of dendritic cells (DCs). Calcium phosphate (CP) nanoparticles (NPs) are biodegradable vehicles with low toxicity and high loading capacity of DNA but suffer from stability issues. Here we employed adenosine triphosphate (ATP) as a dual functional agent, i.e. stabiliser for CP and immunological adjuvant, and applied the ATP-modified CP (ACP) NPs to the DNA vaccine. ACP NP-enhanced cellular uptake and improved transfection efficiency of DNA vaccine, and further showed the ability to activate DCs that are critical for them to prime T cells in cancer immunotherapy. As a result, a higher level of antigen-specific antibody with stronger tumour growth inhibition was achieved in mice immunised with the ACP-DNA vaccine. Overall, this one-step synthesised ACP NPs are an efficient nano-delivery system and nano-adjuvant for cancer DNA vaccines.

Nucleic acid vaccines and CpG oligodeoxynucleotides for allergen immunotherapy.

PURPOSE OF REVIEW: Molecular forms of allergen-specific immunotherapy (AIT) are continuously emerging to improve the efficacy of the treatment, to shorten the duration of protocols and to prevent any side effects. The present review covers the recent progress in the development of AIT based on nucleic acid encoding allergens or CpG oligodeoxynucleotides (CpG-ODN). RECENT FINDINGS: Therapeutic vaccinations with plasmid deoxyribonucleic acid (DNA) encoding major shrimp Met e 1 or insect For t 2 allergen were effective for the treatment of food or insect bite allergy in respective animal models. DNA expressing hypoallergenic shrimp tropomyosin activated Foxp3+ T regulatory (Treg) cells whereas DNA encoding For t 2 down-regulated the expression of pruritus-inducing IL-31. Co-administrations of major cat allergen Fel d 1 with high doses of CpG-ODN reduced Th2 airway inflammation through tolerance induction mediated by GATA3+ Foxp3hi Treg cells as well as early anti-inflammatory TNF/TNFR2 signaling cascade. Non-canonical CpG-ODN derived from Cryptococcus neoformans as well as methylated CpG sites present in the genomic DNA from Bifidobacterium infantis mediated Th1 or Treg cell differentiation respectively. SUMMARY: Recent studies on plasmid DNA encoding allergens evidenced their therapeutic potential for the treatment of food allergy and atopic dermatitis. Unmethylated or methylated CpG-ODNs were shown to activate dose-dependent Treg/Th1 responses. Large clinical trials need to be conducted to confirm these promising preclinical data. Moreover, tremendous success of messenger ribonucleic acid (mRNA) vaccines against severe acute respiratory syndrome coronavirus 2 must encourage as well the re-exploration of mRNA vaccine platform for innovative AIT.

Potential Therapeutic Targets and Vaccine Development for SARS-CoV-2/COVID-19 Pandemic Management: A Review on the Recent Update.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is a highly pathogenic novel virus that has caused a massive pandemic called coronavirus disease 2019 (COVID-19) worldwide. Wuhan, a city in China became the epicenter of the outbreak of COVID-19 in December 2019. The disease was declared a pandemic globally by the World Health Organization (WHO) on 11 March 2020. SARS-CoV-2 is a beta CoV of the Coronaviridae family which usually causes respiratory symptoms that resemble common cold. Multiple countries have experienced multiple waves of the disease and scientific experts are consistently working to find answers to several unresolved questions, with the aim to find the most suitable ways to contain the virus. Furthermore, potential therapeutic strategies and vaccine development for COVID-19 management are also considered. Currently, substantial efforts have been made to develop successful and safe treatments and SARS-CoV-2 vaccines. Some vaccines, such as inactivated vaccines, nucleic acid-based, and vector-based vaccines, have entered phase 3 clinical trials. Additionally, diverse small molecule drugs, peptides and antibodies are being developed to treat COVID-19. We present here an overview of the virus interaction with the host and environment and anti-CoV therapeutic strategies; including vaccines and other methodologies, designed for prophylaxis and treatment of SARS-CoV-2 infection with the hope that this integrative analysis could help develop novel therapeutic approaches against COVID-19.

An update review of globally reported SARS-CoV-2 vaccines in preclinical and clinical stages.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the rapidly spreading pandemic COVID-19 in the world. As an effective therapeutic strategy is not introduced yet and the rapid genetic variations in the virus, there is an emerging necessity to design, evaluate and apply effective new vaccines. An acceptable vaccine must elicit both humoral and cellular immune responses, must have the least side effects and the storage and transport systems should be available and affordable for all countries. These vaccines can be classified into different types: inactivated vaccines, live-attenuated virus vaccines, subunit vaccines, virus-like particles (VLPs), nucleic acid-based vaccines (DNA and RNA) and recombinant vector-based vaccines (replicating and non-replicating viral vector). According to the latest update of the WHO report on April 2nd, 2021, at least 85 vaccine candidates were being studied in clinical trial phases and 184 candidate vaccines were being evaluated in pre-clinical stages. In addition, studies have shown that other vaccines, including the Bacillus Calmette-Guérin (BCG) vaccine and the Plant-derived vaccine, may play a role in controlling pandemic COVID-19. Herein, we reviewed the different types of COVID-19 candidate vaccines that are currently being evaluated in preclinical and clinical trial phases along with advantages, disadvantages or adverse reactions, if any.

Enhancing Immune Responses to a DNA Vaccine Encoding Toxoplasma gondii GRA7 Using Calcium Phosphate Nanoparticles as an Adjuvant.

Toxoplasma gondii infects almost all warm-blooded animals, including humans. DNA vaccines are an effective strategy against T. gondii infection, but these vaccines have often been poorly immunogenic due to the poor distribution of plasmids or degradation by lysosomes. It is necessary to evaluate the antigen delivery system for optimal vaccination strategy. Nanoparticles (NPs) have been shown to modulate and enhance the cellular humoral immune response. Here, we studied the immunological properties of calcium phosphate nanoparticles (CaPNs) as nanoadjuvants to enhance the protective effect of T. gondii dense granule protein (GRA7). BALB/c mice were injected three times and then challenged with T. gondii RH strain tachyzoites. Mice vaccinated with GRA7-pEGFP-C2+nano-adjuvant (CaPNs) showed a strong cellular immune response, as monitored by elevated levels of anti-T. gondii-specific immunoglobulin G (IgG), a higher IgG2a-to-IgG1 ratio, elevated interleukin (IL)-12 and interferon (IFN)-γ production, and low IL-4 levels. We found that a significantly higher level of splenocyte proliferation was induced by GRA7-pEGFP-C2+nano-adjuvant (CaPNs) immunization, and a significantly prolonged survival time and decreased parasite burden were observed in vaccine-immunized mice. These data indicated that CaPN-based immunization with T. gondii GRA7 is a promising approach to improve vaccination.

CpG Oligonucleotides as Vaccine Adjuvants.

CpG Oligonucleotides (ODN) are immunomodulatory synthetic oligonucleotides specifically designed to stimulate Toll-like receptor 9. TLR9 is expressed on human plasmacytoid dendritic cells and B cells and triggers an innate immune response characterized by the production of Th1 and pro-inflammatory cytokines. This chapter reviews recent progress in understanding the mechanism of action of CpG ODN and provides an overview of human clinical trial results using CpG ODN to improve vaccines for the prevention/treatment of cancer, allergy, and infectious disease.

Understanding Pseudomonas aeruginosa-Host Interactions: The Ongoing Quest for an Efficacious Vaccine.

Pseudomonas aeruginosa is a leading cause of chronic respiratory infections in people with cystic fibrosis (CF), bronchiectasis or chronic obstructive pulmonary disease (COPD), and acute infections in immunocompromised individuals. The adaptability of this opportunistic pathogen has hampered the development of antimicrobial therapies, and consequently, it remains a major threat to public health. Due to its antimicrobial resistance, vaccines represent an alternative strategy to tackle the pathogen, yet despite over 50 years of research on anti-Pseudomonas vaccines, no vaccine has been licensed. Nevertheless, there have been many advances in this field, including a better understanding of the host immune response and the biology of P. aeruginosa. Multiple antigens and adjuvants have been investigated with varying results. Although the most effective protective response remains to be established, it is clear that a polarised Th2 response is sub-optimal, and a mixed Th1/Th2 or Th1/Th17 response appears beneficial. This comprehensive review collates the current understanding of the complexities of P. aeruginosa-host interactions and its implication in vaccine design, with a view to understanding the current state of Pseudomonal vaccine development and the direction of future efforts. It highlights the importance of the incorporation of appropriate adjuvants to the protective antigen to yield optimal protection.

Leishmania infantum pyridoxal kinase evaluated in a recombinant protein and DNA vaccine to protects against visceral leishmaniasis.

Leishmania infantum pyridoxal kinase (PK) protein was characterized after an immunoproteomics screening performed with the sera from patients suffering visceral leishmaniasis (VL). Since it was recognized by sera of mammalian hosts infected by a viscerotropic Leishmania species, PK could emerge as a new vaccine candidate against disease, due to its antigenicity and immunogenicity. In this context, in the present study, the effects of the immunization using PK were evaluated when administered as a DNA plasmid (pDNAA3/PK) or recombinant protein (rPK) plus saponin. The immune response elicited by both vaccination regimens reduced in significant levels the parasite load in spleen, liver, draining lymph nodes and bone marrow, being associated with the development of Th1-type immune response, which was characterized by high levels of IFN-γ, IL-12, GM-CSF, and specific IgG2a antibody, besides low production of IL-4, IL-10, and protein and parasite-specific IgG1 antibodies. CD8+ T cells were more important in the IFN-γ production in the pDNAA3/PK group, while CD4+ T cells contributed more significantly to production of this cytokine in the rPK/Saponin group. In addition, increased IFN-γ secretion, along with low levels of IL-10, were found when PBMCs from VL patients after treatment and healthy individuals were stimulated with the protein. In conclusion, when administered either as a DNA plasmid or recombinant protein plus adjuvant, PK can direct the immune response towards a Th1-type immune profile, protecting mice against L. infantum challenge; therefore, it can be seen as a promising immunogen against human VL.

Novel Therapies for Treatment of Food Allergy.

Food allergy prevalence has increased over the past 2 decades and is estimated to affect 8% of children and 4% to 10% of adults. There is an unmet need to evaluate new therapeutic modalities that may decrease the risk of food-induced anaphylaxis and improve patients' quality of life. Oral, epicutaneous, and sublingual food immunotherapies have different safety and efficacy profiles, and their long-term outcome and applicability are unclear. Food allergy trials are currently evaluating different biologics (given as monotherapy or adjunct to immunotherapy), modified food proteins, DNA vaccines, and fecal microbiota transplantation.

Advances in Management of Food Allergy in Children.

Food allergy is a potentially life-threatening medical condition and a significant public health concern worldwide. The current management consists of strict avoidance of the culprit food and treating any adverse reactions from unintended food ingestion. The increasing prevalence of food allergy encouraged research and clinical trials in the field of specific allergen immunotherapy (AIT) which represents an appealing approach, especially in pediatric age. AIT consists of the gradual administration of growing amounts of the offending allergen in order to induce food desensitization, which is an increase in the threshold for reactivity while continuing on regular exposure to the allergen. AIT can be administered through oral, sublingual, epicutaneous, and subcutaneous routes. Reports on oral immunotherapy (OIT) thus far have been more extensive. The desirable goal is to achieve "post desensitization effectiveness", that is the ability to introduce food without reaction even after a period of discontinuation of the offending food. Other therapeutic approaches are being studied alongside immunotherapy such as modified proteins, probiotics, Chinese herbal supplements, biologic therapies, and DNA vaccines.

Principles of Allergen Immunotherapy and Its Clinical Application in China: Contrasts and Comparisons with the USA.

Allergen immunotherapy (AIT) for allergic rhinitis (AR), asthma, and other allergic diseases has developed quickly. House dust mite (HDM), Artemisia (wormwood), Humulus japonicus (Japanese hop), Alternaria alternata, and Cladosporium herbarum are the five most common inhalant allergens in China. AIT has been performed in China for over 60 years. With the support of the Chinese Medical Association (CMA) and the Chinese Medical Doctors Association (CMDA), the Chinese College of Allergy and Asthma (CCAA) was established in 2016 as a specialized branch of CDMA and is the main certification authority for AIT. Chinese allergists and scientists have made tremendous progress in the development of AIT. There have been many publications by Chinese allergists and scientists worldwide encompassing original research studies, systematic reviews, case studies, and clinical trials. Currently, conventional subcutaneous immunotherapy (SCIT) is the preferred AIT in China, but sublingual immunotherapy (SLIT) is beginning to gain recognition. An increasing number of clinical trials have been conducted to investigate the clinical efficacy and side effects of SLIT and SCIT. In China, HDM is the only commercial standardized allergen extracts in clinical use, whereas the others are crude allergen extracts. Besides standardized allergen extracts, other forms of hypoallergenic extracts are still being investigated and developed in China. Immunotherapy in China is similar to that in the USA in which allergen extracts can be mixed for SCIT. However, allergen extracts cannot be mixed for SCIT in Europe.

Protective efficacy induced by DNA prime and recombinant protein boost vaccination with Toxoplasma gondii GRA14 in mice.

Toxoplasma gondii, the etiological agent of toxoplasmosis, can cause severe or lethal damages in both animals and man. So, tends to develop a more effective vaccine to prevent this disease is extremely needed and would be so prominent. The novel dense granule antigen 14 (GRA14) has been identified as a potential vaccine candidate against T. gondii infection. The aim of this study was evaluation of protective immunity induced by prime/boost vaccination strategy of GRA14 antigen with calcium phosphate (CaPNs) or Aluminum hydroxide (Alum) nano-adjuvants in BALB/c mice. The finding showed that immunization with the prime-boost strategy using plasmid DNA (pcGRA14) and recombinant protein (rGRA14) with nano-adjuvants significantly elicited levels of specific IgG antibodies and cytokines against T. gondii infection. Given that, there were the high levels of total IgG, IgG2a, IFN-γ in mice of rGRA14-CaPNs and pcGRA14 + rGRA14-CaPNs groups, which indicating a Th-1 type response. While immunization of mice with Alum based rGRA14 and pcGRA14 + rGRA14 elicited specific IgG1 and IL-4 levels, which was confirmed a Th-2 type response. Mice immunized with DNA prime-protein boost vaccine with nano-adjuvants produce more vigorous specific lymphoproliferative responses than mice immunized with other antigen formulations. In addition, the CaPNs-based prime-boost vaccine of pcGRA14 + rGRA14 showed the longest survival time in mice and the lowest parasitic load in their brain tissue compared to the other groups. The results obtained in this study show that the use of GRA14 based DNA prime-protein boost vaccination regime with CaPNs can dramatically enhanced both humoral and cellular immune responses. Therefore, this strategy can provide a promising approach to the development of an effective vaccine against T. gondii infection in the future.

Antigenic Epitope Analysis and Efficacy Evaluation of GRA41 DNA Vaccine Against T. gondii Infection.

BACKGROUND: Toxoplasma gondii has a comprehensive impact on a great range of warm-blood mammals, in which one-third of the population all over the world is involved. Dense granular proteins, regarded as GRA family, mediating substantial interface between host cell cytoplasm and parasite, are widely studied for preventing the infection of T. gondii. PURPOSE: As is handled in our study, the effect of intramuscularly injecting the genetic vaccine pEGFP-C1/GRA41 encoding a novel dense granule protein, GRA41, was evaluated. METHODS: At the beginning, bioinformatics analysis was used to evaluate epitopes of both B cells and T cells on the GRA41 protein of T. gondii. Afterwards, recombinant plasmids (pEGFP-C1/GRA41) were injected into BALB/c mice and the quantity of IgG and its subclass IgG2a remarkably increased. IFN-γ, distinctive from the other cytokines (IL-4, and IL-10), was significant in growth. Afterwards, the intraperitoneal challenge was executed for recording survival time with tachyzoites with high virulence (in RH strain) and counting the number of brain cysts was carried out after the infection of PRU strain (low virulence). RESULTS: In pEGFP-C1/GRA41 group, the survival period was significantly longer (13.3 ± 3.37 days) after tachyzoites attack with the RH strain in high virulence, compared with the other groups (less than 8 days). Additionally, the cyst quantity is remarkably lower and the rate of reduction could reach 59.34%. CONCLUSION: All the results indicated effective protection of DNA vaccine encoding GRA41 against T. gondii.

Cancer DNA vaccines: current preclinical and clinical developments and future perspectives.

The recent developments in immuno-oncology have opened an unprecedented avenue for the emergence of vaccine strategies. Therapeutic DNA cancer vaccines are now considered a very promising strategy to activate the immune system against cancer. In the past, several clinical trials using plasmid DNA vaccines demonstrated a good safety profile and the activation of a broad and specific immune response. However, these vaccines often demonstrated only modest therapeutic effects in clinical trials due to the immunosuppressive mechanisms developed by the tumor. To enhance the vaccine-induced immune response and the treatment efficacy, DNA vaccines could be improved by using two different strategies. The first is to increase their immunogenicity by selecting and optimizing the best antigen(s) to be inserted into the plasmid DNA. The second strategy is to combine DNA vaccines with other complementary therapies that could improve their activity by attenuating immunosuppression in the tumor microenvironment or by increasing the activity/number of immune cells. A growing number of preclinical and clinical studies are adopting these two strategies to better exploit the potential of DNA vaccination. In this review, we analyze the last 5-year preclinical studies and 10-year clinical trials using plasmid DNA vaccines for cancer therapy. We also investigate the strategies that are being developed to overcome the limitations in cancer DNA vaccination, revisiting the rationale for different combinations of therapy and the different possibilities in antigen choice. Finally, we highlight the most promising developments and critical points that need to be addressed to move towards the approval of therapeutic cancer DNA vaccines as part of the standard of cancer care in the future.