Helper Epitopes Research Articles

Designing novel multiepitope mRNA vaccine targeting Hendra virus (HeV): An integrative approach utilizing immunoinformatics, reverse vaccinology, and molecular dynamics simulation.

Human and animal health is threatened by Hendra virus (HeV), which has few treatments. This in-silico vaccine design study focuses on HeV G (glycoprotein), F (fusion protein), and M (matrix protein). These proteins were computationally assessed for B and T-cell epitopes after considering HeV strain conservation, immunogenicity, and antigenicity. To improve vaccination immunogenicity, these epitopes were selectively ligated into a multiepitope construct. To improve vaccination longevity and immunological response, adjuvants and linkers were ligated. G, F, and M epitopes were used to create an mRNA HeV vaccine. Cytotoxic, helper, and linear B-lymphocytes' epitopes are targeted by this vaccine. The population coverage analysis demonstrates that multi-epitope vaccination covers 91.81 percent of CTL and 98.55 percent of HTL epitopes worldwide. GRAVY evaluated the vaccine's well-characterized physicochemical properties -0.503, indicating solubility and functional stability. Structure analysis showed well-stabilized 2° and 3° structures in the vaccine, with alpha helix, beta sheet, and coil structures (Ramachandran score of 88.5% and Z score of -3.44). There was a strong affinity as shown by docking tests with TLR-4 (central score of -1139.4 KJ/mol) and TLR-2 (center score of -1277.9 KJ/mol). The coupled V-apo, V-TLR2, and V-TLR4 complexes were tested for binding using molecular dynamics simulation where extremely stable complexes were found. The predicted mRNA structures provided significant stability. Codon optimization for Escherichia. coli synthesis allowed the vaccine to attain a GC content of 46.83% and a CAI score of 1.0, which supports its significant expression. Immunological simulations indicated vaccine-induced innate and adaptive immune reactions. Finally, this potential HeV vaccine needs more studies to prove its efficacy and safety.

Immunoinformatic approach to design an efficient multi-epitope peptide vaccine against melanoma.

Melanoma is known to be the most hazardous and life-threatening type of skin cancer. Although numerous treatments have been authorized in recent years, they often result in severe side effects and may not fully cure the disease. To combat this issue, immunotherapy has emerged as a promising approach for the prevention and treatment of melanoma. Specifically, the use of epitope melanoma vaccine, a subset of immunotherapy, has recently gained attention. The aim of this study was to create a multi-epitope melanoma vaccine using immunoinformatic methods. Two well-known antigens, NYESO-1 and MAGE-C2, were selected due to their strong immunogenicity and high expression in melanoma. To enhance the immunogenicity of the peptide vaccine, Brucella cell-surface protein 31 (BCSP31), the G5 domain of resuscitation-promoting factor B (RpfB) adjuvants, and the helper epitope of pan HLADR-binding epitope (PADRE) were incorporated to vaccine construct. These different segments were connected with suitable linkers and the resulting vaccine structure was evaluated for its physicochemical, structural, and immunological properties using computational tools. The designed vaccine was found to have satisfactory allergenicity, antigenicity, and physicochemical parameters. Additionally, a high-quality tertiary structure of the vaccine was achieved through modeling, refinement, and validation. Docking and molecular dynamics studies showed that the vaccine had a stable and appropriate interaction with the cognate TLR2 and TLR4 receptors during the simulation period. Finally, in silico immune simulation analysis revealed a significant increase in the levels of helper and cytotoxic T cells, as well as the cytokines interferon-gamma and interleukin-2, after repeated exposure to the melanoma vaccine. These results suggest that the designed vaccine has the potential to be an effective therapeutic option for melanoma. However, additional in vitro and in vivo validations are crucial to assess real-world efficacy and safety.

Anti-Cytokine Active Immunotherapy Based on Supramolecular Peptides for Alleviating IL-1β-Mediated Inflammation.

IL-1β is a principal proinflammatory cytokine underlying multiple local and systemic chronic inflammatory conditions including psoriasis, rheumatoid arthritis, inflammatory bowel disease, and type 2 diabetes. Passive immunotherapies and biologic drugs targeting IL-1β, while offering significant clinical benefit, nevertheless have limitations such as significant non-response rates, induction of anti-drug antibodies, and high costs. Here, an active immunotherapy raising antibody responses against IL-1β employing self-assembling peptide nanofibers is described. The nanofibers contain defined quantities of B-cell epitopes from IL-1β and exogenous T helper epitopes and employ the Q11 self-assembling peptide platform. Without adjuvant, the nanofibers raised durable anti-IL-1β antibody responses that inhibit IL-1β activity in vitro and in vivo. In a mouse model of imiquimod-induced psoriasis, prophylactic immunizations with the nanofibers diminished symptoms of epidermal thickening. This therapeutic effect is associated with biasing the immune response toward an anti-inflammatory IgG1/Th2 phenotype and a lowered expression of proinflammatory genes in the skin. Further, anti-IL-1β nanofibers induced therapeutic immunosuppressive CD62L+ Treg cells. This technology represents a potential alternative for passive immunotherapies and other biologics for treating chronic inflammatory conditions.

Abstract 3741: Helper/killer hybrid epitope long peptide (H/K-HELP) cancer vaccine augments Th1-dependent CTL induction at tumor-draining lymph node to eradicate solid tumor: its application to develop an innovative combination cancer immunotherapy(iCCI)

Abstract We have initially demonstrated the pivotal role of IFN-γ-producing tumor-antigen-specific Th1 cells for the complete eradication of established tumor mass by CTL. The accumulated evidence has clearly demonstrated that induction of Th1-dependent full activation of CTL at tumor-draining lymph nodes (TDLN) are crucial for inducing complete rejection of solid tumor by CTL. To induce Th1 immunity efficiently at TDLN in tumor-bearing host, we developed an artificially synthesized helper/killer-hybrid epitope long peptide (H/K-HELP), which conjugated killer and helper epitope peptides of cancer antigen by a glycine-linker. In mouse model, OVA-H/K-HELP was selectively presented in vivo by professional DC in vaccinated TDLN and sustained antigen presentation capability of DC to stimulate both CTL and Th1 cells. Thus, in contrast to short peptide, vaccination of OVA-expressing EG7-bearing mice with OVA-H/K-HELP caused a complete eradication of EG7 tumor mass. To apply these basic findings to clinical treatment of cancer patients, we then developed Survivin-H/K-HELP. Treatment of a patient with a triple-negative breast cancer patient with Survivin-H/K-HELP induced a complete response in a triple-negative breast cancer patient concomitantly with the induction of Th1-dependent cellular and humoral immune responses. In this clinical study, the patients showed Th1-dependent C’-fixing IgG antibody production and exhibited IFN-γ-producing Th1 cellular responses. Finally, we also applied H/K-HELP-pulsing DC-vaccine to develop an innovative combination cancer immunotherapy (iCCI). The iCCI consisting of radiation, low dose of immune check point inhibitors (ICIs:Nibolumab, Ipilimumab) and H/K-HELP-pulsed DC, all of which have been shown to initially modulate antitumor immunity at TDLN. Here, we described a successful outcome of a case of the stage IVA inoperable advanced hypopharyngeal squamous cell cancer patient with lymph node-metastasis. The iCCI treatment of the patient caused a complete disappearance of all cancers and the patient has been cancer free for over 15 months so far. Although the destruction mechanism of cancer is not determined, we image this iCCI might improve patient’s antitumor immune capability in immune microenvironment around tumor (IMAT) including TDLN and TME. Our developed iCCI will become a promising strategy to overcome inoperable advanced cancers in future. Citation Format: Takanori Iwasaki, Yuichiro Yazaki, Takashi Masuko, Takashi Nishimura. Helper/killer hybrid epitope long peptide (H/K-HELP) cancer vaccine augments Th1-dependent CTL induction at tumor-draining lymph node to eradicate solid tumor: its application to develop an innovative combination cancer immunotherapy(iCCI) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3741.

Cholesterol as an inbuilt immunoadjuvant for a lipopeptide vaccine against group A Streptococcus infection

Peptide-based vaccines can trigger highly specific immune responses, although peptides alone are usually unable to confer strong humoral or cellular immunity. Consequently, peptide antigens are administered with immunostimulatory adjuvants, but only a few are safe and effective for human use. To overcome this obstacle, herein a peptide antigen was lipidated to effectively anchor it to liposomes and emulsion. A peptide antigen B cell epitope from Group A Streptococcus M protein was conjugated to a universal T helper epitope, the pan DR-biding epitope (PADRE), alongside a lipidic moiety cholesterol. Compared to a free peptide antigen, the lipidated version (LP1) adopted a helical conformation and self-assembled into small nanoparticles. Surprisingly, LP1 alone induced the same or higher antibody titers than liposomes or emulsion-based formulations. In addition, antibodies produced by mice immunized with LP1 were more opsonic than those induced by administering the antigen with incomplete Freund’s adjuvant. No side effects were observed in the immunized mice and no excessive inflammatory immune responses were detected. Overall, this study demonstrated how simple conjugation of cholesterol to a peptide antigen can produce a safe and efficacious vaccine against Group A Streptococcus – the leading cause of superficial infections and the bacteria responsible for deadly post-infection autoimmune disorders.

A bioinformatic analysis: Previous allergen exposure may support anti- SARS-CoV-2 immune response

COVID-19, caused by infection with the SARS-CoV-2 has become a global health problem due to significant mortality rates; the exact pathophysiological mechanism remains uncertain. Articles reporting patient data are quite heterogeneous and have several limitations. Surviving patients develop a CD4 and CD8 T-cell response to the virus SARS-CoV-2 during COVID-19. Interestingly, pre-existing virus-reactive T-cells have been found in patients that were not infected before, suggesting some form of cross-reactivity or immunological mimicry. To better understand this phenomenon, we performed a bioinformatic study, which was aimed to identify antigenic structures that may explain the presence of such “reactive” T-cells, which may support or modulate the immune response to SARS-CoV-2 infections. Seven different common environmental allergen epitopes identical to the SARS-CoV-2 S-protein were identified that share affinity to 8 MHCI-specific epitope regions. Pollen showed the greatest similarity with the S protein epitope. In the epitope similarity analysis between the S protein and MHC-II / T helper epitopes, the highest similarity was determined for mites. When S-protein that stimulates B cells and identical epitope antigens are examined, the most common allergens were hornbeam and wheat. The high epitope similarity observed for the allergens examined and S protein epitopes suggest that these allergens may be a reason for pre-existing SARS-CoV-2 – reactive T-cells in previously non-infected subjects and such a previous exposure may affect the course of the disease in COVID-19 infection. It remains to be determined whether such a previous existence of SARS-CoV-2 reactive cells can support the clearance of the virus or if they, in contrast, may even aggravate the disease course. (Table 4, Ref 54)

Nanoparticles Carrying Conserved Regions of Influenza A Hemagglutinin, Nucleoprotein, and M2 Protein Elicit a Strong Humoral and T Cell Immune Response and Protect Animals from Infection.

Current influenza vaccines are mainly strain-specific and have limited efficacy in preventing new influenza A strains. Efficient control of infection can potentially be achieved through the development of broad-spectrum vaccines based on conserved antigens. A combination of several such antigens, including the conserved region of the second subunit of the hemagglutinin (HA2), the extracellular domain of the M2 protein (M2e), and epitopes of nucleoprotein (NP), which together can elicit an antibody- and cell-mediated immune response, would be preferred for vaccine development. In this study, we obtained recombinant virus-like particles formed by an artificial self-assembling peptide (SAP) carrying two epitopes from NP, tandem copies of M2e and HA2 peptides, along with a T helper Pan DR-binding epitope (PADRE). Fusion proteins expressed in Escherichia coli self-assembled in vitro into spherical particles with a size of 15-35 nm. Immunization of mice with these particles induced strong humoral immune response against M2e and the entire virus, and lead to the formation of cytokine-secreting antigen-specific CD4+ and CD8+ effector memory T cells. Immunization provided high protection of mice against the lethal challenge with the influenza A virus. Our results show that SAP-based nanoparticles carrying conserved peptides from M2, HA, and NP proteins of the influenza A virus, as well as T helper epitope PADRE, can be used for the development of universal flu vaccines.

In silico designing a novel TLR4-mediating multiepitope vaccine against monkeypox via advanced immunoinformatics and bioinformatics approaches

Monkeypox virus is a member of the Poxviridae family, which causes monkeypox zoonotic disease. Since July 2022, the prevention of monkeypox have become more considerable due to the new outbreak, making it a global concern. Therefore, we used an in silico-based method, including immunoinformatics, bioinformatics, molecular docking, and gene cloning approaches to design a novel multiepitope vaccine against monkeypox. Three immunogenic envelope proteins of monkeypox virus, including G10R, E8L, and A30L, were selected to predict appropriate immune system stimulator epitopes. The A30L is common between smallpox and monkeypox virus, so the proposed vaccine may be effective against smallpox too. There is no evidence of allergenicity and toxicity of the vaccine epitopes. To boost the immunogenicity of the designed vaccine, we used the helper epitope of PADRE and RS01as adjuvants. Furthermore, some linkers are used to link epitopes and adjuvants together. The physicochemical futures of the designed vaccine were assessed. The tertiary structure of the vaccine was modeled and then refined to improve its structure and physicochemical properties. To analyze the vaccine construct and TLR4 complex affinity, they were docked to gather. Besides, the vaccine was cloned into E.coli. pET-21b(+) plasmid to reveal that it can be expressed and stimulate the immune system. Immune stimulation evaluation showed that the candidate vaccine could induce the production of IgM, IgG1, and IgG2 antibodies. Overall, we suggested an effective vaccine candidate against monkeypox. However, Future studies and clinical trials should be done to ensure the efficacy and safety of this vaccine. Communicated by Ramaswamy H. Sarma

Multiepitope Subunit Peptide-Based Nanovaccine against Porcine Circovirus Type 2 (PCV2) Elicited High Antibody Titers in Vaccinated Mice.

Porcine circovirus 2 (PCV2) infection is one of the most serious threats to the swine industry. While the disease can be prevented, to some extent, by commercial PCV2a vaccines, the evolving nature of PCV2 necessitates the development of a novel vaccine that can compete with the mutations of the virus. Thus, we have developed novel multiepitope vaccines based on the PCV2b variant. Three PCV2b capsid protein epitopes, together with a universal T helper epitope, were synthesized and formulated with five delivery systems/adjuvants: complete Freund's adjuvant, poly(methyl acrylate) (PMA), poly(hydrophobic amino acid), liposomes and rod-shaped polymeric nanoparticles built from polystyrene-poly(N-isopropylacrylamide)-poly(N-dimethylacrylamide). Mice were subcutaneously immunized with the vaccine candidates three times at three-week intervals. All vaccinated mice produced high antibody titters after three immunizations as analyzed by the enzyme-linked immunosorbent assay (ELISA), while mice vaccinated with PMA-adjuvanted vaccine elicited high antibody titers even after a single immunization. Thus, the multiepitope PCV2 vaccine candidates designed and examined here show strong potential for further development.

Phylogenetic and Immune Epitope Analysis of Hepatitis B Surface Antigen in Chronic Carriers from Tabriz, Northwest of Iran

Background: The purpose of this investigation was to specify the genotypes and subtypes of hepatitis B virus (HBV) by phylogenetic analysis and to investigate the mutations in the S gene region in chronic patients with hepatitis B surface antigen (HBsAg)-positive. Methods: In the present study, Serum sample of 95 patients with chronic HBV infection were subjected. Nested polymerase chain reaction was used for detection of HBV DNA. The S gene region of the DNA isolates was subjected to direct sequencing and phylogenetic analysis. Results: Genotype D was present in all isolates, and the predominant subtype was ayw2 (94.7%), followed by three isolates, ayw3 (3.1%), and two isolates, ayw4 (2.1%). There were totally 169 nucleotide changes. Eighty-one (47.92%) were missense, while 88 (52.07%) were silent. None of the nucleotide or amino acid changes were seen in 31 (32.6%) patients. Eight (8.4%) of the 95 samples had at least one mutation in the HBsAg "a" determinant region. Fifty-eight (71.6%) of the 81 amino acid changes in the surface protein occurred in immunological epitopes, with 16 (27.5%) occurring in B cell epitopes, 17 (29.3%) in T helper epitopes, and 25 (43.1%) in internal cytotoxic T lymphocyte epitopes. Conclusion: This investigation demonstrated that the genotype D is the prevalent genotype in Eastern Azerbaijan province, similar to other Iranian areas and Mediterranean nations. Furthermore, the highest rate of mutation of antigenic epitopes occurred in the T lymphocyte epitopes of our patients.

Immunoinformatics analysis of candidate proteins for controlling bovine paratuberculosis.

Paratuberculosis is debilitating chronic enteritis usually characterized by diarrhea, decreased milk production, and progressive cachexia. Mycobacterium avium subspecies paratuberculosis (MAP) causes significant economic losses by affecting dairy herds globally. Development of protective vaccines is considered as one of the most effective controlling measures for MAP infections. In the current study, hydrophilic parts of MAP2191 and FAP-P proteins as two vaccine candidates were analyzed using immunoinformatics approaches. After selecting the most hydrophilic parts of MAP2191 and FAP-P, helper and cytotoxic T-cell epitopes of ht-MAP2191 and ht-FAP-P were identified. The immunogenic, toxicity and physicochemical properties were assessed. Secondary structures of these proteins were predicted, and their tertiary structures were modeled, refined, and validated. Linear and conformational epitopes of corresponding B-cells were recognized. Then ht-MAP2191 and ht-FAP-P epitopes were employed for molecular docking simulations. The results indicated that ht-MAP2191 and ht-FAP-P were immunogenic, non-allergenic, and non-toxic and possess potent T-cell and B-cell epitopes. Eventually, these protein constructs were docked favorably against TLR4. According to the findings, ht-MAP2191 and ht-FAP-P could be effective protein-based vaccine candidates for paratuberculosis. It should be noted that to examine their efficacy, further in vitro and in vivo experiments are underway.

Cancer-specific T helper shared and neo-epitopes uncovered by expression of the MHC class II master regulator CIITA.

We report an approach to identify tumor-specific CD4+ Tcell neo-epitopes of both mouse and human cancer cells by analysis of major histocompatibility complex (MHC) class II-eluted natural peptides. MHC class II-presented peptide sequences are identified by introducing the MHC class II transactivator (CIITA) in tumor cells that were originally MHC class II negative. CIITA expression facilitates cell-surface expression of MHC class II molecules and the appropriate peptide-loading machinery. Peptide elution of purified MHC class II molecules and subsequent mass spectrometry reveals oncoviral- and neo-epitopes as well as shared epitopes. Immunological relevance of these epitopes is shown by natural presentation by dendritic cells and immunogenicity. Synthetic peptide vaccination induced functional CD4+ Tcell responses, which helped tumor control invivo. Thus, this CIITA transfection approach aids to identify relevant T helper epitopes presented by any MHC class II allele that would be otherwise very difficult to predict and reveals important targets for cancer immunotherapy.

Design and Functional Characterization of HIV-1 Envelope Protein-Coupled T Helper Liposomes.

Functionalization of experimental HIV-1 virus-like particle vaccines with heterologous T helper epitopes (T helper VLPs) can modulate the humoral immune response via intrastructural help (ISH). Current advances in the conjugation of native-like HIV-1 envelope trimers (Env) onto liposomes and encapsulation of peptide epitopes into these nanoparticles renders this GMP-scalable liposomal platform a feasible alternative to VLP-based vaccines. In this study, we designed and analyzed customizable Env-conjugated T helper liposomes. First, we passively encapsulated T helper peptides into a well-characterized liposome formulation displaying a dense array of Env trimers on the surface. We confirmed the closed pre-fusion state of the coupled Env trimers by immunogold staining with conformation-specific antibodies. These peptide-loaded Env-liposome conjugates efficiently activated Env-specific B cells, which further induced proliferation of CD4+ T cells by presentation of liposome-derived peptides on MHC-II molecules. The peptide encapsulation process was then quantitatively improved by an electrostatically driven approach using an overall anionic lipid formulation. We demonstrated that peptides delivered by liposomes were presented by DCs in secondary lymphoid organs after intramuscular immunization of mice. UFO (uncleaved prefusion optimized) Env trimers were covalently coupled to peptide-loaded anionic liposomes by His-tag/NTA(Ni) interactions and EDC/Sulfo-NHS crosslinking. EM imaging revealed a moderately dense array of well-folded Env trimers on the liposomal surface. The conformation was verified by liposomal surface FACS. Furthermore, anionic Env-coupled T helper liposomes effectively induced Env-specific B cell activation and proliferation in a comparable range to T helper VLPs. Taken together, we demonstrated that T helper VLPs can be substituted with customizable and GMP-scalable liposomal nanoparticles as a perspective for future preclinical and clinical HIV vaccine applications. The functional nanoparticle characterization assays shown in this study can be applied to other systems of synthetic nanoparticles delivering antigens derived from various pathogens.

Abstract 3563: CD8+ T cell-mediated tumor rejection by an Adeno-associated virus-like particle (AAVLP) vaccine

Abstract The utilization of adeno-associated viruses (AAVs) as vaccines has primarily been focused on the induction of antibody responses. Displaying antigens derived from HER2 or HPV on the AAV capsid surface lead to strong humoral immune responses. However, the potential of AAVs as T cell inducing vaccines has been poorly investigated. Model antigens have been inserted into the capsid of AAVs to analyze T cell responses, but these studies rather focused on preventing vector immunity for an improved tolerance of gene therapies. By using this as a starting point, we set out to test AAVs as T cell inducing vaccines with the prospect of targeting cancer neoantigens. In first experiments, the general properties of the vaccination strategy were estimated by displaying the ovalbumin-derived model antigen SIINFEKL on the surface of adeno-associated virus-like particles (AAVLPs). Upon injection of the AAVLP-SIINFEKL vaccine, mice developed strong CD8+ T cell responses against the displayed antigen. Highest immune responses were achieved by subcutaneous hock injection of AAVLPs, adjuvanted by Montanide ISA 51 VG. SIINFEKL-specific T cell responses peaked around three weeks after vaccination, whereas a memory subset remained present for long term. The anti-tumor efficacy of the vaccine was shown by injecting SIINFEKL-expressing B16F10 melanoma cells subcutaneously into mice, in which the tumor was completely rejected after vaccination. Interestingly, the induction of CD8+ T cell responses and the tumor protection depended on the presence of CD4+ T cells. Accordingly, T helper epitopes were identified in the AAVLP capsid sequence. In addition to the initial tests, a set of murine neoantigens, derived from B16F10 cells, were displayed on AAVLPs. In direct comparison to a peptide vaccine, which did not have an effect on tumor growth, the AAVLP vaccine had a significant impact on the tumor growth rate. In conclusion, AAVLPs show promising effects as T cell vaccines. The vaccination strategy can be used to induce cytotoxic T cell responses in general and anti-tumor effects in particular. AAV capsid-specific helper epitopes is one inherent advantage, since the AAVLP vaccine delivers immune stimulation within the viral particle itself. Thus, antigen-displaying AAVLPs could be an alternative to current gold standards in the field of neoantigen vaccines and have a prospect for future clinical applications. Citation Format: Lasse Neukirch, Patrick Schmidt, Inka Zörnig, Dirk Jäger, Silke Uhrig-Schmidt. CD8+ T cell-mediated tumor rejection by an Adeno-associated virus-like particle (AAVLP) vaccine [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3563.

SARS-CoV-2 Omicron Variant is Expected to Retain Most of the Spike Protein Specific Dominant T-Cell Epitopes Presented by COVID-19 Vaccines - Worldwide, 2021.

What is already known about this topic?The newly emerged variant of Omicron, which carries many of the mutations found in other variants of concern (VOCs), as well as a great number of new mutations that may enhance its immune escape, has spread rapidly around the world. This has raised public concern about the effectiveness of the current coronavirus disease 2019 (COVID-19) vaccine.What is added by this report?In this study, different bioinformatic softwares were applied to predict the dominant Omicron spike (S) protein cytotoxic T lymphocyte (CTL) and T helper (Th) epitopes in representative world population and Chinese population. Compared to the original severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) S protein, limited mutations were identified within the dominant CTL and Th epitopes in Omicron variant.What are the implications for public health practice?The results of this study suggested that the current COVID-19 vaccine-induced T-cell immunity may still provide significant protection against Omicron variant infection in fully vaccinated individuals.

Improving potency of Nanoliposomal AE36 peptide vaccine by adding CD4+ T cell helper epitope and MPL in TUBO breast cancer mice model

Cancer peptide vaccines stimulate the immune system and activate efficient T cell responses towards cancerous cells. Despite this, the scant efficacy of peptide vaccines has led to modest clinical success in most instances. Hence, optimizing cancer peptide vaccines to enhance their effectiveness appeared to be critical to achieving successful treatment. Designing multiepitope peptide formulations using appropriate delivery systems is a promising strategy for increasing peptide vaccines' efficacy and triggering robust immune responses. Therefore, we studied a liposomal-based peptide vaccine composed of AE36 (HER2/neu-derived peptide) and PADRE (Pan HLA-DR peptide) as well as monophosphoryl lipid A (MPL) adjuvant. Then the prophylactic immune response was evaluated in BALB/c mice breast cancer models bearing TUBO tumors. We found that the liposomal form of AE36 peptide plus PADRE resulted in improved activation of CD4+ and CD8+ T cell responses and considerably increased production of IFN-γ. In addition, the presence of PADRE, as a CD4+ T helper epitope could enhance the potency of the liposomal AE36 peptide vaccine. Furthermore, this formulation resulted in a considerable reduction in tumor volume and increased survival in a murine model. Our findings suggest that a liposomal formulation containing the multiepitope peptides AE36, PADRE, and MPL could be a potential prophylactic vaccine candidate that triggers a robust antigen-specific immune response of CD8+ CTLs.

Structure-activity relationship of lipid, cyclic peptide and antigen rearrangement of physically mixed vaccines

Currently there is no approved vaccine to prevent and/or treat group A Streptococcus (GAS) infection. With increasing reports of GAS antibiotic resistance, vaccine adjuvants and targeted delivery systems which induce a strong immune response are a widely acknowledged unmet need. Through extensive structure-activity studies, we investigated a cyclic decapeptide physically mixed with a GAS B cell peptide epitope (J8), a universal T helper epitope (PADRE), and different synthetic lipidic moieties as a conceivable self-adjuvanting GAS vaccine. We explored the structure (orientation)-relationship of the chemically-conjugated B cell epitope and T helper epitope peptide as part of this physically-mixed vaccine. Following in vivo assessment in mice, these cyclic lipopeptide vaccines showed successful induction of J8-specific systemic IgG antibodies when administered subcutaneously without additional adjuvant. Interestingly, an exposed C-terminus of the GAS B cell epitope and a 16-carbon alpha-amino fatty acid lipid was required for strong immunoreactivity, capable of effectively opsonising multiple strains of clinically-isolated GAS bacteria. Physicochemical assessment proved the alpha helix structure of the GAS B cell epitope was retained, impacting particle self-assembly and vaccine immunoreactivity. This study showed the capability for a self-adjuvanting cyclic delivery system to act as a vehicle for the delivery of GAS peptide antigens to treat GAS infection.

Physical mixture of a cyclic lipopeptide vaccine induced high titres of opsonic IgG antibodies against group A streptococcus.

Untreated or reoccurring group A Streptococcus (GAS) infection can lead to a number of post-infection complications, including rheumatic heart disease. There is no licenced vaccine for the treatment or prevention of GAS infection. We identified that a cyclic decapeptide plays a significant positive influence on the adjuvant activity of several lipid-antigen mixtures. Here, three synthetic vaccine components were synthesised: (1) J8-PADRE represents the GAS B cell antigen (J8) conjugated to the universal T helper epitope (PADRE); (2) a synthetic toll like receptor 2 (TLR2) ligand based on a C16 alkyl chain lipid moiety; and (3) a cyclic carrier deca-peptide. Previously, through structure-immune activity investigations, it was observed that a physical mixture of these three components had significantly higher IgG immune responses when compared to a fully conjugated vaccine construct. Expanding the scope of this structure-activity investigation, we show that the presence of the cyclic peptide is required for the induction of a strong, balanced Th1/Th2 immune response when compared with lipid and antigen only, and cyclic lipopeptide plus B/T cell antigen physical mixtures.

TMOD-14. CONJOINED CLASS I AND II EPITOPES ENHANCE NEOANTIGEN-TARGETED ACTIVE IMMUNOTHERAPY

Abstract INTRODUCTION Cancer vaccines involve the administration of tumor-associated antigens into the host to generate anti-tumor T cell responses. Glioblastoma (GBM) is a disease with poor prognosis. GBM has a limited number of immunotherapeutic targets due to low mutational load, and is also highly heterogeneous; targeting a single antigen leads to antigen escape and tumor growth. METHODS VMDK mice were subcutaneously implanted with 750,000 SMA560 cells and on days 1 and 8 post implantation, mice were treated with 15 nmol of the universal helper epitope, P30, conjoined to the MHCI-restricted neoepitopes Odc1MHCI-P30 or Topbp1MHCI-P30. Human CD27 (hCD27) transgenic mice were intracranially implanted with CT2A-Odc1, followed by anti-CD27 and 15 nmol of Odc1MHCI-P30. B16.OVA or B16.F10 tumor cells were intracranially implanted in hCD27 mice and received SIINFEKL-P30 or Trp2-P30 conjoined peptides. Tumor growth, survival, or IFNγ secretion of splenic or tumor-infiltrating cells was assessed. RESULTS Unlike Odc1MHCI mixed with P30, conjoined Odc1MHCI-P30 had equivalent immunogenicity and anti-tumor efficacy to that observed with native long Odc1 peptide. Native long peptide of Topbp1 did not elicit an antitumor response, yet Topbp1MHCI-P30 caused an increase in numbers of IFNγ-secreting splenocytes and a decrease in tumor growth and similar to that seen with Odc1MHCI-P30 . Anti-CD27 treatment significantly increased numbers of IFNγ secreting splenocytes in Odc1MHCI-P30 vaccinated hCD27 mice, and the use of anti-CD27 with Odc1MHCI-P30 achieved long-term survival in 90% of tumor bearing hCD27 mice. Anti-CD27 synergized with SIINFEKL-P30 and Trp2-P30 to significantly improve survival after administration of these peptides. CONCLUSIONS Our work shows that poorly immunogenic neoantigens can be conjoined to P30 and used to generate an anti-tumor response in mouse models of GBM, and anti-tumor responses of conjoined peptides can be enhanced with anti-CD27 treatment. Together, these data demonstrate the efficacy of neoantigen vaccines for the treatment of heterogeneous GBM.

A Phase II Randomized, Double-Blind, Placebo-Controlled, Multicenter Trial to Evaluate the Efficacy of Cmvpepvax for Preventing CMV Reactivation/Disease after Matched Related/Unrelated Donor Hematopoietic Cell Transplant

A Phase II Randomized, Double-Blind, Placebo-Controlled, Multicenter Trial to Evaluate the Efficacy of Cmvpepvax for Preventing CMV Reactivation/Disease after Matched Related/Unrelated Donor Hematopoietic Cell Transplant