Current Insights into CAR T-Cell-Based Therapies for Myelodysplastic Syndrome.

Myelodysplastic syndromes (MDS) are due to defective hematopoiesis in bone marrow characterized by cytopenia and dysplasia of blood cells, with a varying degree of risk of acute myeloid leukemia (AML). Currently, the only potentially curative strategy is hematopoietic stem cell transplantation (HSCT). Many patients are ineligible for HSCT, due to late diagnosis, presence of co-morbidities, old age and complications likely due to graft-versus-host disease (GvHD). As a consequence, patients with MDS are often treated conservatively with blood transfusions, chemotherapy, immunotherapy etc. based on the grade and manifestations of MDS. The development of chimeric antigen receptor (CAR)-T cell therapy has revolutionized immunotherapy for hematological malignancies, as evidenced by a large body of literature. However, resistance and toxicity associated with it are also a challenge. Hence, there is an urgent need to develop new strategies for immunological and hematopoetic management of MDS. Herein, we discuss current limitations of CAR T-cell therapy and summarize novel approaches to mitigate this. Further, we discuss the in vivo activation of tumor-specific T cells, immune check inhibitors (ICI) and other approaches to normalize the bone marrow milieu for the management of MDS.

Designing and development of efficient multi-epitope-based peptide vaccine candidate against emerging avian rotavirus strains: A vaccinomic approach.

BACKGROUND: Enteric avian rotavirus (ARV) is the etiological agent of several health problems that pose a global threat to commercial chickens. Therefore, to avoid these widespread epidemics and high mortality rates, only vaccine and strict biosecurity are required. METHOD: The present study employs computational techniques to design a unique multi-epitope-based vaccine candidate that successfully activates immune cells against the ARV by combining adjuvant, linker, and B and T-cell epitopes. Starting, homologous sequences in the various ARV serotypes were revealed in the NCBI BLAST database, and then the two surface proteins (VP4 and VP7) of the ARV were retrieved from the UniprotKB database. The Clustal Omega server was then used to identify the conserved regions among the homologous sequences, and the B and T-cell epitopes were predicted using IEDB servers. Then, superior epitopes-2 MHC-1 epitopes, 2 MHC-2 epitopes, and 3B-cell epitopes-were combined with various adjuvants to create a total of four unique vaccine candidates. Afterward, the designed vaccine candidates underwent computational validation to assess their antigenicity, allergenicity, and stability. The vaccine candidate (V2) that demonstrated non-antigenicity, a high VaxiJen score, and non-allergenicity was ultimately chosen for molecular docking and dynamic simulation. RESULTS: Although the V2 and V4 vaccine candidates were highly immunogenic, V2 had a higher solubility rate. The predicted values of the aliphatic index and GRAVY value were 30.4 and 0.417, respectively. In terms of binding energy, V2 outperformed V4. Being successfully docked with TLRs, V2 was praised as the finest. After adaptation, the sequence's 50.73 % GC content outside of the BglII or ApaI restriction sites indicated that it was equivalently safe to clone. The chosen sequence was then inserted into the pET28a(+) vector within the BglII and ApaI restriction sites. This resulted in a final clone that was 4914 base pairs long, with the inserted sequence accounting for 478 bp and the vector accounting for the remainder. CONCLUSIONS: The immune-mediated simulation results for the selected vaccine construct showed significant response; thus, the study confirmed that the selected V2 vaccine candidate could enhance the immune response against ARV.

Vaccination of cattle with a virus vector vaccine against a major membrane protein of Mycobacterium avium subsp. paratuberculosis elicits CD8 cytotoxic T cells that kill intracellular bacteria.

Analysis of the recall response ex vivo in cattle vaccinated with a Mycobacterium avium subsp. paratuberculosis (Map) rel deletion mutant revealed the immune response was directed toward a 35 kD major membrane protein (MMP) of Map. Antigen presenting cells (APC) primed with MMP elicited expansion of CD8 cytotoxic memory T cells (CTL) with ability to kill intracellular bacteria. Development of CTL was MHC-restricted. The gene MAP2121c, encoding MMP, was modified for expression of MMP (tPA-MMP-2mut) in a mammalian cell line to explore the potential of developing MMP as a vaccine. Ex vivo stimulation of PBMC, from Map free cattle, with APC primed with tPA-MMP-2mut expressed p35 elicited a primary CD8 CTL response comparable to the recall response elicited with PBMC from cattle vaccinated with either the Maprel deletion mutant or MMP. In the present study, the modified gene for MMP, now referred to as p35NN, was placed into a bovine herpes virus-4 (BoHV4) vector to determine the potential use of BoHV-4AΔTK-p35NN as a peptide-based vaccine. Subcutaneous vaccination of healthy cattle with BoHV-4AΔTK-p35NN elicited a CTL recall response, as detected ex vivo. The results show use of a virus vector is an effective way for delivery of MMP as a vaccine. The immunogenic activity of MMP was not lost when modified for expression in mammalian cells. The next step is to conduct a field trial to determine if presence of an immune response to MMP prevents Map from establishing an infection.

A phase 3, randomized, double-blind, multicenter, placebo-controlled study of S-588410, a five-peptide cancer vaccine as an adjuvant therapy after curative resection in patients with esophageal squamous cell carcinoma.

BACKGROUND: S-588410, a cancer peptide vaccine (CPV), comprises five HLA-A*24:02-restricted peptides from five cancer-testis antigens. In a phase 2 study, S-588410 was well-tolerated and exhibited antitumor efficacy in patients with urothelial cancer. Therefore, we aimed to evaluate the efficacy, immune response, and safety of S-588410 in patients with completely resected esophageal squamous cell carcinoma (ESCC). METHODS: This phase 3 study involved patients with HLA-A*24:02-positive and lymph node metastasis-positive ESCC who received neoadjuvant therapy followed by curative resection. After randomization, patients were administered S-588410 and placebo (both emulsified with Montanide™ ISA 51VG) subcutaneously. The primary endpoint was relapse-free survival (RFS). The secondary endpoints were overall survival (OS), cytotoxic T-lymphocyte (CTL) induction, and safety. Statistical significance was tested using the one-sided weighted log-rank test with the Fleming-Harrington class of weights. RESULTS: A total of 276 patients were randomized (N = 138/group). The median RFS was 84.3 and 84.1 weeks in the S-588410 and placebo groups, respectively (P = 0.8156), whereas the median OS was 236.3 weeks and not reached, respectively (P = 0.6533). CTL induction was observed in 132/134 (98.5%) patients who received S-588410 within 12 weeks. Injection site reactions (137/140 patients [97.9%]) were the most frequent treatment-emergent adverse events in the S-588410 group. Prolonged survival was observed in S-588410-treated patients with upper thoracic ESCC, grade 3 injection-site reactions, or high CTL intensity. CONCLUSIONS: S-588410 induced immune response and had acceptable safety but failed to reach the primary endpoint. A high CTL induction rate and intensity may be critical for prolonging survival during future CPV development.

Efficacy of MAGE-A4 long peptide as a universal immunoprevention cancer vaccine.

BACKGROUND: The clinical application of peptide vaccines in tumor immunotherapy holds significant promise. Peptide-based tumor vaccines are currently subject to certain limitations in clinical trials, including the challenge of inducing a sustained response from CD4+ T helper cells and cytotoxic T lymphocytes (CTL), as well as human leukocyte antigen (HLA) restrictions. METHODS: Through the utilization of biological information methodology, a screening process was conducted to identify three potential long peptides that are specifically targeted by the MAGE-A4 antigen. The candidate long peptides were subjected to in vitro testing using human peripheral blood lymphocytes as samples to evaluate their immunogenicity and immune function. The antitumor properties and preliminary mechanism of the long peptide vaccine were investigated through the use of a mouse model designed for the prevention of triple negative breast cancer (TNBC). RESULTS: Three predicted multi-epitope long peptides targeting MAGE-A4 have shown to have a strong immunogenicity, with a total positive rate of 72% across different HLA subtypes in Chinese populations. they can also increase the levels of the costimulatory factor CD137 and tumor necrosis factor-alpha (TNF-α), activate T cells, and boost the cytotoxic activity. Results from an animal study have revealed that the long-peptide vaccine, both on its own and in combination with R848, has displayed impressive anti-tumor and target-specific capabilities. Moreover, it has the ability to increase the expression of effector memory T cells and central memory T cells. CONCLUSIONS: This study was the first to screen three multi-epitope long peptides targeting MAGE-A4 and assess their immunogenicity, immune function, and potential as adjuvant peptides. The results showed that the MAGE-A4 long peptide vaccine can be used as a novel immunoprophylaxis method to prevent TNBC. Moreover, the proposed development model is capable of screening multiple target antigens, which lead to its clinical application.

Multi-epitope peptide vaccines targeting dengue virus serotype 2 created via immunoinformatic analysis.

The Middle East has witnessed a greater spread of infectious Dengue viruses, with serotype 2 (DENV-2) being the most prevalent form. Through this work, multi-epitope peptide vaccines against DENV-2 that target E and nonstructural (NS1) proteins were generated through an immunoinformatic approach. MHC class I and II and LBL epitopes among NS1 and envelope E proteins sequences were predicted and their antigenicity, toxicity, and allergenicity were investigated. Studies of the population coverage denoted the high prevalence of NS1 and envelope-E epitopes among different countries where DENV-2 endemic. Further, both the CTL and HTL epitopes retrieved from NS1 epitopes exhibited high conservancies' percentages with other DENV serotypes (1, 3, and 4). Three vaccine constructs were created and the expected immune responses for the constructs were estimated using C-IMMSIM and HADDOCK (against TLR 2,3,4,5, and 7). Molecular dynamics simulation for vaccine construct 2 with TLR4 denoted high binding affinity and stability of the construct with the receptor which might foretell favorable in vivo interaction and immune responses.

Immunoinformatics-Based Design of Multi-epitope DNA and mRNA Vaccines Against Zika Virus.

In this study, we used an immunoinformatics approach to predict antigenic epitopes of Zika virus (ZIKV) proteins to assist in designing a vaccine antigen against ZIKV. We performed the prediction of CD8+ T-lymphocyte and antigenic B-cell epitopes of ZIKV proteins. The binding interactions of T-cell epitopes with major histocompatibility complex class I (MHC-I) proteins were assessed. We selected the antigenic, conserved, nontoxic, and immunogenic epitopes, which indicated significant interactions with the human leucocyte antigen (HLA-A and HLA-B) alleles and worldwide population coverage of 76.35%. The predicted epitopes were joined with the help of linkers and an adjuvant. The vaccine antigen was then analyzed through molecular docking with TLR3 and TLR8, and it was in silico cloned in the pVAX1 vector to be used as a DNA vaccine and designed as a mRNA vaccine.

The immune response behind peptide vaccination in diffuse midline glioma.

A first-in-human trial demonstrated that a vaccine targeting the histone mutation H3K27M can induce an immune response, in a mutation-specific manner, in patients with diffuse midline glioma. In a recent study by Boschert et al., the same group now dissects the functional immune response triggered after effective vaccination of one of the patients, who has been in remission for over 3 years. The H3K27M peptide vaccine, named H3-vac, induces a CD4+ T-cell-specific immune response in this patient and expands the repertoire of polyclonal H3K27M-specific T-cell receptors. A clonal H3K27M-reactive B-cell population was also detected in the patient's cerebrospinal fluid. Importantly, the immune response is induced across various human leukocyte antigen alleleotypes, indicating the potential efficacy of the vaccine in diverse populations. By exploring in detail the immune response linked to this patient's long-term survival, the authors prove peptide vaccinations as a viable therapeutic approach. This paves the way for personalised therapies harnessing immunogenic T- and B-cell responses against different tumour types.

Preventive effects of vasohibin-2-targeting peptide vaccine for diabetic nephropathy.

Diabetic nephropathy remains the leading cause of end-stage kidney disease in many countries, and additional therapeutic targets are needed to prevent its development and progression. Some angiogenic factors are involved in the pathogenesis of diabetic nephropathy. Vasohibin-2 (VASH2) is a novel proangiogenic factor, and our previous study showed that glomerular damage is inhibited in diabetic Vash2 homozygous knockout mice. Therefore, we established a VASH2-targeting peptide vaccine as a tool for anti-VASH2 therapy in diabetic nephropathy. In this study, the preventive effects of the VASH2-targeting peptide vaccine against glomerular injury were examined in a streptozotocin (STZ)-induced diabetic mouse model. The mice were subcutaneously injected with the vaccine at two doses 2 wk apart and then intraperitoneally injected with 50 mg/kg STZ for 5 consecutive days. Glomerular injury was evaluated 20 wk after the first vaccination. Treatment with the VASH2-targeting peptide vaccine successfully induced circulating anti-VASH2 antibody without inflammation in major organs. Although the vaccination did not affect blood glucose levels, it significantly prevented hyperglycemia-induced increases in urinary albumin excretion and glomerular volume. The vaccination did not affect increased VASH2 expression but significantly inhibited renal angiopoietin-2 (Angpt2) expression in the diabetic mice. Furthermore, it significantly prevented glomerular macrophage infiltration. The preventive effects of vaccination on glomerular injury were also confirmed in db/db mice. Taken together, the results of this study suggest that the VASH2-targeting peptide vaccine may prevent diabetic glomerular injury in mice by inhibiting Angpt2-mediated microinflammation.NEW & NOTEWORTHY This study demonstrated preventive effects of VASH2-targeting peptide vaccine therapy on albuminuria and glomerular microinflammation in STZ-induced diabetic mouse model by inhibiting renal Angpt2 expression. The vaccination was also effective in db/db mice. The results highlight the importance of VASH2 in the pathogenesis of early-stage diabetic nephropathy and the practicability of anti-VASH2 strategy as a vaccine therapy.

AutoPepVax, a Novel Machine-Learning-Based Program for Vaccine Design: Application to a Pan-Cancer Vaccine Targeting EGFR Missense Mutations.

The current epitope selection methods for peptide vaccines often rely on epitope binding affinity predictions, prompting the need for the development of more sophisticated in silico methods to determine immunologically relevant epitopes. Here, we developed AutoPepVax to expedite and improve the in silico epitope selection for peptide vaccine design. AutoPepVax is a novel program that automatically identifies non-toxic and non-allergenic epitopes capable of inducing tumor-infiltrating lymphocytes by considering various epitope characteristics. AutoPepVax employs random forest classification and linear regression machine-learning-based models, which are trained with datasets derived from tumor samples. AutoPepVax, along with documentation on how to run the program, is freely available on GitHub. We used AutoPepVax to design a pan-cancer peptide vaccine targeting epidermal growth factor receptor (EGFR) missense mutations commonly found in lung adenocarcinoma (LUAD), colorectal adenocarcinoma (CRAD), glioblastoma multiforme (GBM), and head and neck squamous cell carcinoma (HNSCC). These mutations have been previously targeted in clinical trials for EGFR-specific peptide vaccines in GBM and LUAD, and they show promise but lack demonstrated clinical efficacy. Using AutoPepVax, our analysis of 96 EGFR mutations identified 368 potential MHC-I-restricted epitope-HLA pairs from 49,113 candidates and 430 potential MHC-II-restricted pairs from 168,669 candidates. Notably, 19 mutations presented viable epitopes for MHC I and II restrictions. To evaluate the potential impact of a pan-cancer vaccine composed of these epitopes, we used our program, PCOptim, to curate a minimal list of epitopes with optimal population coverage. The world population coverage of our list ranged from 81.8% to 98.5% for MHC Class II and Class I epitopes, respectively. From our list of epitopes, we constructed 3D epitope-MHC models for six MHC-I-restricted and four MHC-II-restricted epitopes, demonstrating their epitope binding potential and interaction with T-cell receptors. AutoPepVax's comprehensive approach to in silico epitope selection addresses vaccine safety, efficacy, and broad applicability. Future studies aim to validate the AutoPepVax-designed vaccines with murine tumor models that harbor the studied mutations.

Development and Evaluation of an Immunoinformatics-Based Multi-Peptide Vaccine against Acinetobacter baumannii Infection.

Multi-drug-resistant (MDR) Acinetobacter baumannii is an opportunistic pathogen associated with hospital-acquired infections. Due to its environmental persistence, virulence, and limited treatment options, this organism causes both increased patient mortality and incurred healthcare costs. Thus, prophylactic vaccination could be ideal for intervention against MDR Acinetobacter infection in susceptible populations. In this study, we employed immunoinformatics to identify peptides containing both putative B- and T-cell epitopes from proteins associated with A. baumannii pathogenesis. A novel Acinetobacter Multi-Epitope Vaccine (AMEV2) was constructed using an A. baumannii thioredoxin A (TrxA) leading protein sequence followed by five identified peptide antigens. Antisera from A. baumannii infected mice demonstrated reactivity to rAMEV2, and subcutaneous immunization of mice with rAMEV2 produced high antibody titer against the construct as well as peptide components. Immunization results in increased frequency of IL-4-secreting splenocytes indicative of a Th2 response. AMEV2-immunized mice were protected against intranasal challenge with a hypervirulent strain of A. baumannii and demonstrated reduced bacterial burden at 48 h. In contrast, all mock vaccinated mice succumbed to infection within 3 days. Results presented here provide insight into the effectiveness of immunoinformatic-based vaccine design and its potential as an effective strategy to combat the rise of MDR pathogens.

Peptide based vaccine designing against endemic causing mammarenavirus using reverse vaccinology approach.

The rodent-borne Arenavirus in humans has led to the emergence of regional endemic situations and has deeply emerged into pandemic-causing viruses. Arenavirus have a bisegmented ambisense RNA that produces four proteins: glycoprotein, nucleocapsid, RdRp and Z protein. The peptide-based vaccine targets the glycoprotein of the virus encountered by the immune system. Screening of B-Cell and T-Cell epitopes was done based on their immunological properties like antigenicity, allergenicity, toxicity and anti-inflammatory properties were performed. Selected epitopes were then clustered and epitopes were stitched using linker sequences. The immunological and physico-chemical properties of the vaccine construct was checked and modelled structure was validated by a 2-step MD simulation. The thermostability of the vaccine was checked followed by the immune simulation to test the immunogenicity of the vaccine upon introduction into the body over the course of the next 100 days and codon optimization was performed. Finally a 443 amino acid long peptide vaccine was designed which could provide protection against several members of the mammarenavirus family in a variety of population worldwide as denoted by the epitope conservancy and population coverage analysis. This study of designing a peptide vaccine targeting the glycoprotein of mammarenavirues may help develop novel therapeutics in near future.

Current status of immunological therapies for rheumatoid arthritis with a focus on antigen-specific therapeutic vaccines.

Rheumatoid arthritis (RA) is recognized as an autoimmune joint disease driven by T cell responses to self (or modified self or microbial mimic) antigens that trigger and aggravate the inflammatory condition. Newer treatments of RA employ monoclonal antibodies or recombinant receptors against cytokines or immune cell receptors as well as small-molecule Janus kinase (JAK) inhibitors to systemically ablate the cytokine or cellular responses that fuel inflammation. Unlike these treatments, a therapeutic vaccine, such as CEL-4000, helps balance adaptive immune homeostasis by promoting antigen-specific regulatory rather than inflammatory responses, and hence modulates the immunopathological course of RA. In this review, we discuss the current and proposed therapeutic products for RA, with an emphasis on antigen-specific therapeutic vaccine approaches to the treatment of the disease. As an example, we describe published results of the beneficial effects of CEL-4000 vaccine on animal models of RA. We also make a recommendation for the design of appropriate clinical studies for these newest therapeutic approaches, using the CEL-4000 vaccine as an example. Unlike vaccines that create or boost a new immune response, the clinical success of an immunomodulatory therapeutic vaccine for RA lies in its ability to redirect autoreactive pro-inflammatory memory T cells towards rebalancing the "runaway" immune/inflammatory responses that characterize the disease. Human trials of such a therapy will require alternative approaches in clinical trial design and implementation for determining safety, toxicity, and efficacy. These approaches include adaptive design (such as the Bayesian optimal design (BOIN), currently employed in oncological clinical studies), and the use of disease-related biomarkers as indicators of treatment success.

Reverse engineering protection: A comprehensive survey of reverse vaccinology-based vaccines targeting viral pathogens.

Vaccines have significantly reduced the impact of numerous deadly viral infections. However, there is an increasing need to expedite vaccine development in light of the recurrent pandemics and epidemics. Also, identifying vaccines against certain viruses is challenging due to various factors, notably the inability to culture certain viruses in cell cultures and the wide-ranging diversity of MHC profiles in humans. Fortunately, reverse vaccinology (RV) efficiently overcomes these limitations and has simplified the identification of epitopes from antigenic proteins across the entire proteome, streamlining the vaccine development process. Furthermore, it enables the creation of multiepitope vaccines that can effectively account for the variations in MHC profiles within the human population. The RV approach offers numerous advantages in developing precise and effective vaccines against viral pathogens, including extensive proteome coverage, accurate epitope identification, cross-protection capabilities, and MHC compatibility. With the introduction of RV, there is a growing emphasis among researchers on creating multiepitope-based vaccines aiming to stimulate the host's immune responses against multiple serotypes, as opposed to single-component monovalent alternatives. Regardless of how promising the RV-based vaccine candidates may appear, they must undergo experimental validation to probe their protection efficacy for real-world applications. The time, effort, and resources allocated to the laborious epitope identification process can now be redirected toward validating vaccine candidates identified through the RV approach. However, to overcome failures in the RV-based approach, efforts must be made to incorporate immunological principles and consider targeting the epitope regions involved in disease pathogenesis, immune responses, and neutralizing antibody maturation. Integrating multi-omics and incorporating artificial intelligence and machine learning-based tools and techniques in RV would increase the chances of developing an effective vaccine. This review thoroughly explains the RV approach, ideal RV-based vaccine construct components, RV-based vaccines designed to combat viral pathogens, its challenges, and future perspectives.

Decade-long WT1-specific CTLs induced by WT1 peptide vaccination.

INTRODUCTION: The peptide-based cancer vaccine targeting Wilms' tumor 1 (WT1) is a promising immunotherapeutic strategy for hematological malignancies. It remains unclear how long and to what extent the WT1-specific CD8 + cytotoxic T cell (CTL) persist after WT1 peptide vaccination. METHODS: The WT1 peptide vaccine was administered with written consent to a patient with CML in the chronic phase who did not respond well to imatinib, and the patient was followed for 12 years after vaccination. Immune monitoring was performed by specific amplification of WT1-specific CTLs using a mixed lymphocyte peptide culture. T-cell receptors (TCRs) of amplified WT1-specific CTLs were analyzed using next-generation sequencing. This study was approved by the Institutional Review Board of our institution. RESULT: WT1-specific CTLs, which were initially detected during WT1 peptide vaccination, persisted at a frequency of less than 5 cells per 1,000,000 CD8 + T cells for more than 10 years. TCR repertoire analysis confirmed the diversity of WT1-specific CTLs 11 years after vaccination. CTLs exhibited WT1 peptide-specific cytotoxicity in vitro. CONCLUSION: The WT1 peptide vaccine induced an immune response that persists for more than 10 years, even after cessation of vaccination in the CML patient.

Immunotherapy targeting tumor-associated antigen in a mouse model of head and neck cancer.

BACKGROUND: The identification of epitope peptides from tumor-associated antigens (TAAs) is informative for developing tumor-specific immunotherapy. However, only a few epitopes have been detected in mouse TAAs of head and neck cancer (HNSCC). METHODS: Novel mouse c-Met-derived T-cell epitopes were predicted by computer-based algorithms. Mouse HNSCC cell line-bearing mice were treated with a c-Met peptide vaccine. The effects of CD8 and/or CD4 T-cell depletion, and vaccine combination with immune checkpoint inhibitors (ICIs) were evaluated. Tumor re-inoculation was performed to assess T-cell memory. RESULTS: We identified c-Met-derived short and long epitopes that elicited c-Met-reactive antitumor CD8 and/or CD4 T-cell responses. Vaccination using these peptides showed remarkable antitumor responses via T cells in which ICIs were not required. The c-Met peptide-vaccinated mice rejected the re-inoculated tumors. CONCLUSIONS: We demonstrated that novel c-Met peptide vaccines can induce antitumor T-cell response, and could be a potent immunotherapy in a syngeneic mouse HNSCC model.

Bivalent Hemagglutinin Cleavage-Site Peptide Vaccines Protect Chickens from Lethal Infections with Highly Pathogenic H5N1 and H5N6 Avian Influenza Viruses.

BACKGROUND: Outbreaks of highly pathogenic avian influenza viruses cause huge economic losses to the poultry industry worldwide. Vaccines that can protect chickens from infections caused by various variants of highly pathogenic H5Nx avian influenza viruses are needed owing to the continuous emergence of new variants. We previously showed that vaccines containing the H5 cleavage-site peptide from clade 2.3.4.4. H5N6 avian influenza virus protects chickens from infection with homologous clade 2.3.4.4. H5N6 avian influenza virus, but not from infection with the heterologous clade 1 H5N1 avian influenza virus. Therefore, we developed bivalent peptide vaccines containing H5 cleavage sites of viruses from both clades to protect chickens from both H5N1 and H5N6 avian influenza viruses. METHODS: Chickens were vaccinated with two doses of a combined peptide vaccine containing cleavage-site peptides from clade 1 and clade 2.3.4.4. highly pathogenic H5N1 and H5N6 avian influenza viruses and then challenged with both viruses. The infected chickens were monitored for survival and their tracheae and cloacae were sampled to check for viral shedding based on the median tissue culture infectious dose of 50 (log10TCID50/mL) in Madin-Darby canine kidney cells. RESULTS: Antibody production was induced at similar levels in the sera of chickens immunized with two doses of the combined peptide vaccines containing cleavage-site peptides from highly pathogenic H5N1 and H5N6 avian influenza viruses. The immunized chickens were protected from infection with both H5N1 and H5N6 avian influenza viruses without viral shedding in the tracheae and cloacae. CONCLUSIONS: Dual-peptide vaccines containing cleavage-site peptides of both clades can protect chickens from highly pathogenic avian influenza virus infections.

Selection of vaccine-candidate peptides from Mycobacterium avium subsp. paratuberculosis by in silico prediction, in vitro T-cell line proliferation, and in vivo immunogenicity.

Mycobacterium avium subspecies paratuberculosis (MAP) is a global concern in modern livestock production worldwide. The available vaccines against paratuberculosis do not offer optimal protection and interfere with the diagnosis of bovine tuberculosis. The aim of this study was to identify immunogenic MAP-specific peptides that do not interfere with the diagnosis of bovine tuberculosis. Initially, 119 peptides were selected by either (1) identifying unique MAP peptides that were predicted to bind to bovine major histocompatibility complex class II (MHC-predicted peptides) or (2) selecting hydrophobic peptides unique to MAP within proteins previously shown to be immunogenic (hydrophobic peptides). Subsequent testing of peptide-specific CD4+ T-cell lines from MAP-infected, adult goats vaccinated with peptides in cationic liposome adjuvant pointed to 23 peptides as being most immunogenic. These peptides were included in a second vaccine trial where three groups of eight healthy goat kids were vaccinated with 14 MHC-predicted peptides, nine hydrophobic peptides, or no peptides in o/w emulsion adjuvant. The majority of the MHC-predicted (93%) and hydrophobic peptides (67%) induced interferon-gamma (IFN-γ) responses in at least one animal. Similarly, 86% of the MHC-predicted and 89% of the hydrophobic peptides induced antibody responses in at least one goat. The immunization of eight healthy heifers with all 119 peptides formulated in emulsion adjuvant identified more peptides as immunogenic, as peptide specific IFN-γ and antibody responses in at least one heifer was found toward 84% and 24% of the peptides, respectively. No peptide-induced reactivity was found with commercial ELISAs for detecting antibodies against Mycobacterium bovis or MAP or when performing tuberculin skin testing for bovine tuberculosis. The vaccinated animals experienced adverse reactions at the injection site; thus, it is recommend that future studies make improvements to the vaccine formulation. In conclusion, immunogenic MAP-specific peptides that appeared promising for use in a vaccine against paratuberculosis without interfering with surveillance and trade tests for bovine tuberculosis were identified by in silico analysis and ex vivo generation of CD4+ T-cell lines and validated by the immunization of goats and cattle. Future studies should test different peptide combinations in challenge trials to determine their protective effect and identify the most MHC-promiscuous vaccine candidates.

Peptide nanovaccine in melanoma immunotherapy.

Melanoma is an especially fatal neoplasm resistant to traditional treatment. The advancement of novel therapeutical approaches has gained attention in recent years by shedding light on the molecular mechanisms of melanoma tumorigenesis and their powerful interplay with the immune system. The presence of many mutations in melanoma cells results in the production of a varied array of antigens. These antigens can be recognized by the immune system, thereby enabling it to distinguish between tumors and healthy cells. In the context of peptide cancer vaccines, generally, they are designed based on tumor antigens that stimulate immunity through antigen-presenting cells (APCs). As naked peptides often have low potential in eliciting a desirable immune reaction, immunization with such compounds usually necessitates adjuvants and nanocarriers. Actually, nanoparticles (NPs) can provide a robust immune response to peptide-based melanoma vaccines. They improve the directing of peptide vaccines to APCs and induce the secretion of cytokines to get maximum immune response. This review provides an overview of the current knowledge of the utilization of nanotechnology in peptide vaccines emphasizing melanoma, as well as highlights the significance of physicochemical properties in determining the fate of these nanovaccines in vivo, including their drainage to lymph nodes, cellular uptake, and influence on immune responses.