Peptide-Based Vaccines: Current Progress and Future Challenges

Protein to biomaterials: Unraveling the antiviral and proangiogenic activities of Ac-Tβ1-17 peptide, a thymosin β4 metabolite, and its implications in peptide-scaffold preparation

Peptide metabolites are emerging biomolecules with numerous possibilities in biomaterial-based regenerative medicine due to their inherent bioactivities. These small, naturally occurring compounds are intermediates or byproducts of larger proteins and peptides, and they can have profound effects, such as antiviral therapeutics, proangiogenic agents, and regenerative medicinal applications. This study is among the first to focus on using thymosin β4 protein-derived metabolites to pioneer novel applications for peptide metabolites in biomaterials. This study found that the novel peptide metabolite acetyl-thymosin β4 (amino acid 1-17) (Ac-Tβ1-17) exhibited significant protease inhibition activity against SARS-CoV-2, surpassing its precursor protein. Additionally, Ac-Tβ1-17 demonstrated beneficial effects, such as cell proliferation, wound healing, and scavenging of reactive oxygen species (ROS) in human umbilical vein endothelial cells (HUVEC). Integrating Ac-Tβ1-17 into a peptide-based scaffold facilitated cell growth and angiogenesis inside the scaffold and through gradual release into the surrounding environment. The Ac-Tβ1-17 peptide treatment induced significant biochemical responses in HUVEC, increasing Akt, ERK, PI3K, MEK, and Bcl-2 gene expression and proangiogenic proteins. Ac-Tβ1-17 peptide treatment showed similar results in ex vivo by enhancing mouse fetal metatarsal growth and angiogenesis. These findings highlight the potential of natural protein metabolites to generate biologically active peptides, offering a novel strategy for enhancing biomaterial compatibility. This approach holds promise for developing therapeutic biomaterials using peptide metabolites, presenting exciting prospects for future research and applications.

Cell-Free Expression of Nipah Virus Transmembrane Proteins for Proteoliposome Vaccine Design

Membrane proteins expressed on the surface of enveloped viruses are potent antigens in a vaccine, yet are difficult to produce and present due to their instability without a lipid scaffold. Current vaccination strategies that incorporate viral membrane proteins, such as live attenuated viruses, inactivated viruses, or extracellular vesicles, have limitations including lengthy production time, poor immunogenicity, extensive processing steps, and/or poor stability. Cell-free protein synthesis of viral membrane proteins offers a rapid, one-step method to assemble vaccine nanoparticles via cotranslational folding of membrane proteins into nanoscale liposomes. Here, we develop a vaccine candidate for the deadly Nipah virus (NiV), a highly lethal virus listed by the World Health Organization as a priority pathogen, by cell-free expressing two full-length Nipah virus membrane proteins. We demonstrate that both NiV fusion protein (NiV F) and NiV glycoprotein (NiV G) can be expressed and cotranslationally integrated into liposomes and that they fold into their native conformation. We find that the removal of a signal peptide sequence and the alteration of liposome lipid composition improve viral membrane protein incorporation. Furthermore, a lipid adjuvant, monophosphoryl lipid A (MPLA), can be readily added to liposomes without disrupting protein-vesicle loading or protein folding conformations. Finally, we demonstrate that our generated liposomal formulations lead to enhanced humoral responses in mice compared to empty and single-protein controls. This work establishes a platform to quickly assemble and present membrane antigens as multivalent vaccines that will enable a rapid response to the broad range of emerging pathogenic threats.

Peptide-Based Strategies in PLGA-Enhanced Tumor Therapy

Peptide-based therapeutics have gained attention in cancer treatment because of their good specificity, low toxicity, and ability to modulate immune responses. However, challenges such as enzymatic degradation and poor bioavailability limit their clinical application. Peptide-functionalized poly(lactic-co-glycolic acid) (PLGA) systems have emerged as a transformative platform in cancer therapy that offers unique advantages, including enhanced stability, sustained release, and precise delivery of therapeutic agents. This review highlights the synergistic integration of peptides with PLGA and addresses key challenges of peptide-based therapeutics. The application of peptide-functionalized PLGA systems encompasses a diverse range of strategies for cancer therapy. In chemotherapy, peptides disrupt critical tumor pathways, induce apoptosis, and inhibit angiogenesis, demonstrating their versatility in targeting various aspects of tumor progression. In immunotherapy, peptides act as antigens to stimulate robust immune responses or as immune checkpoint inhibitors to restore T cell activity, overcoming tumor immune evasion. These systems also harness the enhanced permeability and retention effect, facilitating preferential accumulation in tumor tissues while leveraging tumor microenvironment (TME)-responsive mechanisms, such as pH-sensitive or enzyme-triggered drug release, to achieve controlled, localized delivery. Collectively, peptide-functionalized PLGA systems represent a promising, versatile approach for precise cancer therapy that integrates innovative delivery strategies with highly specific, potent therapeutic agents.

Computer Integrated Dominant Epitopes Evoke Protective Immune Response Against Streptococcus pneumoniae

Streptococcus pneumoniae is a gram-positive bacterium responsible for various diseases like pneumonia, acute otitis media, sinusitis, meningitis and bacteraemia. These diseases cause a significant amount of morbidity and mortality. Although polysaccharide vaccines are available, the protection provided by these vaccines is serotype-dependent and not enough in sensitive populations like children and older people. Designing a subunit vaccine by using proteins that are responsible for the pathogenesis of diseases can provide better protection against bacterial infections. In this study, we present the design of a novel multi-epitope vaccine against Streptococcus pneumoniae using an immunoinformatic approach. More than 1170 epitopes were identified against B cells, cytotoxic T lymphocytes and helper T lymphocytes from more than 60 pneumococcal proteins. Epitopes were further screened, and potential epitopes were selected for vaccine development. Seven different vaccine combinations that harbour the 15 dominant B-cell, cytotoxic T cell and helper T cell epitopes were evaluated with linker and β-defensin adjuvant to finalise the best vaccine construct. Bioinformatics tools were used to analyse the construct's physicochemical properties, secondary and tertiary structures, allergenicity, antigenicity and immunogenicity. Docking studies with the TLR-4 receptor and molecular dynamics simulations indicated strong binding affinity and stability. In silico immune response simulations predicted robust IgG immune response generation and observed more than 200 000 IgG1 + IgG2 counts per mL. Similarly, cell-mediated immunity was also enhanced by the designed vaccine construct. The construct was codon-optimised and cloned in silico for expression in Escherichia coli. These findings suggest that the construct is a promising candidate for further experimental validation.

In Vivo Evaluation of Pam2Cys-Modified Cancer-Testis Antigens as Potential Self-Adjuvanting Cancer Vaccines

Peptide-based vaccines, formulated with an appropriate adjuvant, offer a versatile platform for targeted cancer immunotherapy. While adjuvants are usually coadministered for nucleic acid and protein vaccines, synthetic peptide antigens afford a more effective opportunity to covalently and regioselectively graft immunostimulatory motifs directly onto the antigen scaffold to yield self-adjuvanting vaccines. Herein, we explore the synthesis of two tissue-restricted cancer-testis antigens (CTAs); New York oesophageal cell carcinoma 1 (NY-ESO-1) and B melanoma antigen 4 (BAGE4), both carrying the toll-like receptor (TLR) agonist, Pam2Cys. These constructs were evaluated in vivo along with a lipid nanoparticle (LNP) preparation of the underexplored BAGE4 melanoma antigen.

Immunogenicity Evaluation of Epitope-Based Vaccine on Target of RNAIII-Activating Protein (TRAP) of Staphylococcus Aureus

Staphylococcus aureus is a leading cause of severe infections in humans and animals, and the emergence of multidrug-resistant strains highlights the need to develop effective vaccines to prevent such diseases. Epitope-based vaccines use short antigen-derived peptides corresponding to immune epitopes, which are administered to trigger protective humoral and cellular immune responses. In this study, in silico MHC affinity measurement methods were used to predict possible binding regions, and five 20-mer synthetic TRAP peptides (TRAPP) were synthesized. Epitope-based vaccines, named PT and PTR, incorporating the identified CD4+ T and B cell epitopes, were constructed. Peptides TRAP20-39 and TRAP94-113 elicited significant peptide-stimulated T-cell proliferation responses in vivo. Additionally, high levels of IFN-γ and IL-17A, along with moderate levels of IL-4, were detected in ex vivo stimulated CD4+ T cells isolated from rTRAP- and TRAPP-immunized mice, suggesting that these peptides are classified as Th1 and Th17 epitopes. Immunization with PT or PTR induces robust humoral and cellular immune responses. Moreover, the epitope-based vaccine, PT, exhibited a stronger protective immune response than the intact TRAP in a murine systemic S. aureus infection model. Based on the results presented herein, an epitope-based vaccine is a promising and potentially more effective candidate.

Electrostatic potential is the dominant force in antigenic selection of naïve T-cells and B-cells for activation and maturation

Peptide antigenicity can be predicted from sequence using a simple method invented by Hopp and Woods in the early 1980's. Since then, a much clearer understanding of T-cell/B-cell signaling and maturation calls for a new understanding of the amino acid determinants of antigenicity. We show that short peptides with more charged side chains generate significantly higher titers of peptide specific antibodies in co-immunized mice. Peptide docking simulations using linearized Poisson-Boltzmann calculations of electrostatic potential show that immunoglobulins distinguish the cognate peptide sequence from randomly selected sequences at "arms length" (10 - 20Å) with >70% of alternative sequences having higher energy at this distance, consistent with the weak specificity observed for naive T-cell and B-cell receptor interactions with MHC-bound antigen. Orders of magnitude lower complexity of the state space of charged surfaces as compared to the state space of surface shapes suggests a dominant role of electrostatics in selecting naive immune cells from the population of circulating cell lines. We propose a two-stage antigen recognition process, first electrostatic and then shape-based, that explains the dominant contribution of charged residues to peptide immunogenicity.

A review of the progress and challenges of developing dendritic-based vaccines against hepatitis B virus (HBV)

Hepatitis B virus (HBV) infections that last a long time are a significant public health problem worldwide. About 254 million people around the world are chronically sick with HBV. Each year, 1.2 million new cases occur, and in 2022, 1.1 million people will die from the disease. So, it has been essential to work on finding ways to treat and avoid HBV. The process of therapeutic vaccination involves giving people a non-infectious form of a virus to start or improve immune reactions specific to HBV. This helps keep HBV infections under control. Dendritic cells (DCs) play a significant part in beginning the adaptive immune response, which could decide how well an HBV infection is treated. DC-based treatment has been looked into for people with chronic HBV (CHB) infection and has shown some sound effects. Vaccines for CHB that use DCs boost antiviral immunity by improving T cells and breaking the immune system's resistance against HBV. In these vaccines, DCs are loaded with HBV antigens (like HBsAg, HBcAg, or peptides) outside of the body and then put back into the patient to make the immune system work better. In conclusion, this DC treatment is a biological therapy method with a good chance of being used. This study examined the different DC-based medicines that can treat and prevent HBV. Finally, we've talked about clinical studies, the current problems, how to fix them, and the future of this vaccine for treating and preventing HBV.

A Chimeric Virus-Like Particle Vaccine Presenting an Immunodominant Epitope of gB Elicited Potent Neutralizing Antibodies against EBV Infection In Vitro and In Vivo

Epstein-Barr Virus (EBV) as the first characterized tumorigenic virus in humans causes heavy disease burdens. An effective vaccine is urgently needed to block EBV infection. Glycoprotein B (gB) is the essential fusogen for EBV infection of all susceptible cell types. We previously demonstrated that neutralizing antibody 3A3 targeting gB effectively blocked EBV infection in a humanized mouse model, indicating that the epitope recognized by 3A3 is the potential immunogen candidate. Hence, we rationally designed a chimeric virus-like particle (cVLP) vaccine based on the hepatitis B core antigen (HBc149) to display gB peptide, αB, recognized by 3A3 (149-αB cVLP). The engineered 149-αB cVLP vaccine self-assembled into spherical particles presenting multiple copies of αB peptide. The 149-αB cVLP vaccine induced much higher antibody titers against αB peptides than gB protein immunization. Importantly, sera antibodies elicited by the 149-αB cVLP vaccine more efficiently blocked EBV infection and membrane fusion of epithelial cells and B cells. Sera from 149-αB cVLP vaccine-immunized rabbits conferred 100% protection against EBV infection in a humanized mouse model. We demonstrated that the 149-αB cVLP vaccine induced potent antigen-specific protective immune responses and shed light on the research of peptide-based vaccines against EBV infection.

Cancer Nanovaccines: Mechanisms, Design Principles, and Clinical Translation

Cancer immunotherapy has transformed the landscape of oncological treatment by employing various strategies to teach the immune system to eliminate tumors. Among these, cancer nanovaccines are an emerging strategy that utilizes nanotechnology to enhance immune activation in response to tumor antigens. This review addresses the principles behind the different technologies in this field aimed at generating a robust and effective immune response. The diversity of strategies adopted for the design of nanovaccines is discussed, including the types of active agents, nanocarriers, their functionalizations, and the incorporation of adjuvants. Furthermore, strategies to optimize nanoparticle formulations to enhance the antigen presentation, target immune cells, and organs and promote strong and durable antitumor responses are explored. Finally, we analyze the current state of clinical application, highlighting ongoing clinical trials and the future potential of cancer nanovaccines. The insights presented in this review aim to guide future research and development efforts in the field, contributing to the advancement of more effective and targeted nanovaccines in the fight against cancer.

Generalization of neoantigen-based tumor vaccine by delivering peptide-MHC complex via oncolytic virus

Neoantigen vaccine is a promising breakthrough in tumor immunotherapy. However, the application of this highly personalized strategy in the treatment of solid tumors is hindered by several obstacles, including very costly and time-consuming preparation steps, uncertainty in prediction algorithms and tumor heterogeneity. Universalization of neoantigen vaccine is an ideal yet currently unattainable solution to such limitations. To overcome these limitations, we engineered oncolytic viruses co-expressing neoantigens and neoantigen-binding major histocompatibility complex (MHC) molecules to force ectopic delivery of peptide-MHC ligands to T cell receptors (TCRs), enabling specific targeting by neoantigen vaccine-primed host immunity. When integrated with neoantigen vaccination, the engineered viruses exhibited potent cytolytic activity in a variety of tumor models irrespective of the neoantigen expression profiles, eliciting robust systemic antitumor immunity to reject tumor rechallenge and inhibit abscopal tumor growth with a favorable safety profile. Thus, this study provides a powerful approach to enhance the universality and efficacy of neoantigen vaccines, meeting the urgent need for universal neoantigen vaccines in the clinic to facilitate the further development of tumor immunotherapy.

Managing thrombus formation with EL2-5HTVac: A selective vaccination-based approach targeting the platelet serotonin 5-HT2AR

Cardiovascular disease is the leading global cause of death, largely attributable to thrombotic events that can result in conditions like myocardial infarction and stroke. The serotonin 2A receptor (5-HT2AR) has been identified as a key mediator in platelet aggregation and thrombogenesis, making it a promising target for antithrombotic therapies. Current 5-HT2AR antagonists, however, have been limited by nonselectivity and adverse effects. This study introduces a novel vaccine designed to target the ligand-binding domain of 5-HT2AR, which resides in the second extracellular loop (EL2). This vaccine, referred to as "EL2-5HTVac," is expected to provide a long-lasting and selective therapeutic approach without the complications of increased bleeding risk. In this study, we demonstrate that EL2-5HTVac induces a robust immune response with a significant elevation in EL2-specific antibodies in comparison with the controls. Furthermore, vaccinated mice exhibited prolonged occlusion times in a FeCl3-induced carotid artery thrombosis model without extending tail bleeding times, indicating a favorable safety profile. The EL2-5HTVac also effectively inhibited the serotonin-induced platelet shape change. Additionally, it also blocked serotonin-enhanced ADP-induced platelet aggregation, suggesting an ability to prevent serotonin-facilitated amplification of platelet activation. These findings suggest that EL2-5HTVac offers a dual advantage of thromboprotection and maintenance of hemostasis, potentially overcoming limitations of existing antithrombotic strategies. Future studies should focus on the long-term efficacy and safety of EL2-5HTVac, as well as the feasibility of a vaccination-based approach in larger animal models for eventual clinical application. SIGNIFICANCE STATEMENT: This study documents the utility of a vaccine as a potential antithrombotic agent. The vaccine can prevent thrombus formation without affecting hemostasis (causing bleeding).

Computational insights in design of Crimean-Congo hemorrhagic fever virus conserved immunogenic nucleoprotein peptides containing multiple epitopes

Crimean-Congo hemorrhagic fever virus (CCHFV) belongs to Nairoviridae family and has tripartite RNA genome. It is endemic in various countries of Asia, Africa, and Europe and is primarily transmitted by Hyalomma ticks but nosocomial transmission also been reported. Vaccines for CCHF are in early phase of clinical trial; therefore, this work is centered on identification of potential immunogenic peptide as vaccine candidates with application of different immunoinformatics approaches. Eleven conserved (>90%) peptides of CCHFV nucleoprotein were selected for CD8+ T-cell (NetMHCpan 4.1b and NetCTLpan 1.1 server) and CD4+ T-cell (NetMHCIIpan-4.0 server and Tepitool) epitope prediction. Three peptides containing multiple CD8+ and CD4+ T-cell and B-cell epitopes were identified on basis of consensus prediction approach. Peptides displayed good antigenicity score of 0.45-0.68 and predicted to bind with diverse human leukocyte antigen (HLA) alleles. Molecular docking was performed with epitopes to HLA and HLA-epitopes complex to T-cell receptor (TCR). In most of the cases, docked complex of HLA-epitope and HLA-epitopes-TCR have the binding energy close to respective natural bound peptide complex with HLA and TCR. Molecular dynamic simulation also revealed that HLA-peptide complexes have minimum fluctuation and deviation than HLA-peptide-TCR docked over 50 ns simulation run. Considering these findings, identified peptides can serve as potential vaccine candidates for CCHFV disease.

Influence of component structural arrangement on cholesterol-antigen conjugate immunogenicity and antisera bactericidal activity against group A Streptococcus

Immune stimulants (adjuvants) are essential vaccine components; however, clinically approved adjuvants are limited with the majority being derived from pathogenic components. In this study, the adjuvanting capacity of cholesterol, a natural human lipid, was explored following conjugation with peptide antigens. A structure-activity relationship study was conducted to compare linear and branched cholesterol conjugates with other lipopeptide vaccines and commercial adjuvants. Group A Streptococcus (GAS) M protein-derived J8 B-cell epitope and a universal helper T-cell epitope P25 were selected as an antigen. In addition, liposomal formulations of the cholesterol-based vaccines were also evaluated in the mouse model. Following subcutaneous and intranasal administration, conjugates comprised of cholesterol, P25 and J8 induced the highest antibody production. Linear cholesterol peptide vaccines triggered strong antibody responses that killed GAS clinical isolates as effectively as responses triggered by commercial adjuvants. The immunogenicity of the vaccines was greatly influenced by the structural arrangement of the vaccine conjugate components. The lead cholesterol conjugate was self-adjuvanting and induced the desired immune response without any exogenous immune stimulation.

Pan-Variant SARS-CoV-2 Vaccines Induce Protective Immunity by Targeting Conserved Epitopes

The development of a globally effective COVID-19 vaccine faces significant challenges, particularly in redirecting the B-cell response from immunodominant yet variable regions of viral proteins toward their conserved domains. To address this, an integrated strategy is implemented that combines classical B-cell epitope prediction with protein-antibody cluster docking and antibody titer analysis from 30 vaccinated and convalescent individuals. This approach yields stable immunodominant and immunoprevalent B-cell epitopes capable of eliciting robust antibody responses in BALB/c mice and effectively neutralizing pseudoviruses expressing the Spike protein of SARS-CoV-2 variants of concern, including Alpha, Beta, Gamma, Delta, and Omicron. To achieve a broader T-cell-based immune response, promiscuous T-cell epitopes are identified by integrating classical T-cell epitope predictions, differential scanning fluorimetry, and peptide-MHC structural analysis. Unique peptides with conserved MHC-anchoring residues are identified, enabling binding to a spectrum of MHC-I and MHC-II haplotypes. These peptides elicit strong interferon gamma responses in human peripheral blood mononuclear cells and demonstrate cross-species efficacy by activating both CD4+ and CD8+ T-cells in BALB/c mice. Collectively, these findings highlight the significance of innovative vaccine strategies targeting immunodominant/immunoprevalent B-cell and promiscuous T-cell epitopes to drive broad and robust humoral and cellular immune responses against a wide range of SARS-CoV-2 variants.

Microenvironment-based immunotherapy in oral cancer: a comprehensive review

Oral cancer, a prevalent form of head and neck malignancy, accounts for 4% of global cancer cases. The most common type, oral squamous cell carcinoma (OSCC), has a survival rate of about 50%. Even though emerging molecular therapies show promise for managing oral cancer, current treatments like surgery, radiotherapy, and chemotherapy have significant side effects. In addition, the complex tumor microenvironment (TME), involving the extracellular matrix (ECM) and cells like fibroblasts and stromal cells like immune cells, promotes tumor growth and inhibits immune responses, complicating treatment. Nonetheless, immunotherapy is crucial in cancer treatment, especially in oral cancers. Indeed, its effectiveness lies in targeting immune checkpoints such as PD-1 and CTLA-4 inhibitors, as well as monoclonal antibodies like pembrolizumab and cetuximab, adoptive cell transfer methods (including CAR-T cell therapy), cytokine therapy such as IL-2, and tumor vaccines. Thus, these interventions collectively regulate tumor proliferation and metastasis by targeting the TME through autocrine-paracrine signaling pathways. Immunotherapy indeed aims to stimulate the immune system, leveraging both innate and adaptive immunity to counteract cancer cell signals and promote tumor destruction. This review will explore how the TME controls tumor proliferation and metastasis via autocrine-paracrine signaling pathways. It will then detail the effectiveness of immunotherapy in oral cancers, focusing on immune checkpoints, targeted monoclonal antibodies, adoptive cell transfer, cytokine therapy, and tumor vaccines.

Tailoring nanovectors for optimal neoantigen vaccine efficacy

The primary objective of neoantigen vaccines is to elicit a robust anti-tumor immune response by generating neoantigen-specific T cells that can eradicate tumor cells. Despite substantial advancements in personalized neoantigen prediction using next-generation sequencing, machine learning, and mass spectrometry, challenges remain in efficiently expanding neoantigen-specific T cell populations in vivo. This challenge impedes the widespread clinical application of neoantigen vaccines. Nanovector-based neoantigen delivery systems have emerged as a promising solutions to this challenge. These nanovectors offer several advantages, such as enhanced stability, targeted intracellular delivery, sustained release, and improved antigen-presenting cell (APC) activation. Notably, they effectively deliver various neoantigen vaccine formulations (DC cell-based, synthetic long peptide (SLP)-based or DNA/mRNA-based) to APCs or T cells, thereby activating both CD4+ T and CD8+ T cells. This ultimately induces a specific anti-tumor immune response. This review focuses on recent innovations in neoantigen vaccine delivery vectors. We aim to identify optimal design parameters for vectors tailored to different neoantigen vaccine types, with an emphasis on enhancing the tumor microenvironment and stimulating the production of neoantigen-specific cytotoxic T cells. By maximizing the potential of these delivery systems, we aim to accelerate the clinical translation of neoantigen nanovaccines and advance cancer immunotherapy.

Lipid Nanoparticles for mRNA Delivery in Cancer Immunotherapy

Cancer immunotherapy is poised to be one of the major modalities for cancer treatment. Messenger RNA (mRNA) has emerged as a versatile and promising platform for the development of effective cancer immunotherapy. Delivery systems for mRNA therapeutics are pivotal for their optimal therapeutic efficacy and minimal adverse side effects. Lipid nanoparticles (LNPs) have demonstrated a great success for mRNA delivery. Numerous LNPs have been designed and optimized to enhance mRNA stability, facilitate transfection, and ensure intracellular delivery for subsequent processing. Nevertheless, challenges remain to, for example, improve the efficiency of endosomal escape and passive targeting. This review highlights key advancements in the development of mRNA LNPs for cancer immunotherapy. We delve into the design of LNPs for mRNA delivery, encompassing the chemical structures, characterization, and structure-activity relationships (SAR) of LNP compositions. We discuss the key factors influencing the transfection efficiency, passive targeting, and tropism of mRNA-loaded LNPs. We also review the preclinical and clinical applications of mRNA LNPs in cancer immunotherapy. This review can enhance our understanding in the design and application of LNPs for mRNA delivery in cancer immunotherapy.

Computational design of a fimbriae-derived multi-epitope vaccine candidate against Klebsiella pneumoniae

Klebsiella pneumoniae is a pathogen that causes infections in various parts of the body, with high mortality rates reported in antibiotic-resistant cases. Treating at-risk individuals requires crucial vaccination efforts due to the challenges that exist. This research involved designing a multi-epitope vaccine from K. pneumoniae's fimbriae antigens. Optimal T-cell and B-cell epitopes were chosen through in silico studies including epitope-HLAs molecular docking. The multi-epitope was created, featuring antigenic T- and B-cell epitopes, β-defensin as an adjuvant, the PADRE sequence to boost immunogenicity and well-suited linkers. The tertiary structure of the multi-epitope was achieved through modeling and molecular dynamics-based refinements. The construct underwent scrutiny for structural traits, physicochemical properties, conformational B epitope prediction, immune responses simulation, in silico cloning, molecular docking for assay binding to toll-like receptors (TLRs), and deformability studies. The outcomes indicated the vaccine candidate's positive attributes, encompassing immunogenicity, structure, physicochemical properties, solubility, TLR binding, toxicity, stability, allergenicity, and cross-reactivity. The multi-epitope vaccine candidate exhibits the potential for provoking diverse immune responses against K. pneumoniae. Nevertheless, additional in vitro and in vivo experimental tests are necessary to substantiate its efficacy.

Advance in peptide-based drug development: delivery platforms, therapeutics and vaccines

The successful approval of peptide-based drugs can be attributed to a collaborative effort across multiple disciplines. The integration of novel drug design and synthesis techniques, display library technology, delivery systems, bioengineering advancements, and artificial intelligence have significantly expedited the development of groundbreaking peptide-based drugs, effectively addressing the obstacles associated with their character, such as the rapid clearance and degradation, necessitating subcutaneous injection leading to increasing patient discomfort, and ultimately advancing translational research efforts. Peptides are presently employed in the management and diagnosis of a diverse array of medical conditions, such as diabetes mellitus, weight loss, oncology, and rare diseases, and are additionally garnering interest in facilitating targeted drug delivery platforms and the advancement of peptide-based vaccines. This paper provides an overview of the present market and clinical trial progress of peptide-based therapeutics, delivery platforms, and vaccines. It examines the key areas of research in peptide-based drug development through a literature analysis and emphasizes the structural modification principles of peptide-based drugs, as well as the recent advancements in screening, design, and delivery technologies. The accelerated advancement in the development of novel peptide-based therapeutics, including peptide-drug complexes, new peptide-based vaccines, and innovative peptide-based diagnostic reagents, has the potential to promote the era of precise customization of disease therapeutic schedule.

Synthetic rEg.P29 Peptides Induce Protective Immune Responses Against Echinococcus granulosus in Mice

Background:Echinococcus granulosus represents a significant threat to animal husbandry and human health, but its consequences are often underestimated. Vaccination can prevent E. granulosus infection. We investigated the immune protective effect induced by the recombinant protein P29 of E. granulosus (rEg.P29) peptide vaccine. Methods: The CD4+ T-, CD8+ T-, Treg-, and CD8+CD107a+ T-cell proportions in the spleen and peripheral blood of infected mice were analyzed using flow cytometry. Additionally, we measured the proportions of IFN-γ and IL-2 secreted by memory T cells, CD19+CD138-B cells, CD19+CD138+ plasmablasts, CD19-CD138+ plasma cells, and CD19+IgD-IgG+ and CD19+IgD-IgA+ memory B cells. Results: No significant differences were noted in CD4+ T-, CD8+ T-, and CD8+CD107a+ Treg-cell percentages among the experimental groups. However, IFN-γ, IL-2, and TNF-α levels and vaccine-specific antibody concentrations in the plasma were significantly elevated in the rEg.P29T+B + CpG + infection and rEg.P29 + CpG + infection groups compared to those in the PBS + infection and CpG + infection groups. Similarly, CD19-CD138+ plasma cell and CD19+IgD-IgG+ and CD19+IgD-IgA+ memory B-cell populations, along with specific antibodies, were significantly higher in these groups. Especially, the average cyst burden in the rEg.P29T+B + CpG + infection and rEg.P29 + CpG + infection groups was significantly reduced compared to that in the PBS + infection and CpG + infection groups. Conclusions: Synthetic peptide vaccines targeting rEg.P29 can effectively inhibit cysts, offering a novel strategy for the development of vaccines against E. granulosus. These findings provide a foundation for further research on the immunogenicity and protective efficacy of rEg.P29-based vaccines.

A Narrative Review of Periodontal Vaccines: Hope or Hype?

Globally, periodontal diseases, mainly driven by polymicrobial biofilms, are a widespread concern of social medicine due to their considerable incidence and tie-up to systemic disorders like diabetes, cardiovascular diseases, and complications during pregnancy. Traditional treatments focus on mechanical debridement and antimicrobial therapies, but these approaches have limitations, including recurrence and antibiotic resistance. Periodontal vaccines offer a promising alternative by targeting the immunological mechanisms underlying periodontal disease. This review explores the current state of periodontal vaccine development, highlighting key antigens, vaccine delivery systems, and preclinical and clinical advancements. Special emphasis is placed on antigen selection, host variability, immune tolerance, and future directions to overcome these barriers. This article highlights the advancements and challenges in periodontal vaccine research, offering insights into the capability of immunoprophylaxis as a groundbreaking way to manage periodontal diseases.

Programmable Stapling Peptide Based on Sulfonium as Universal Vaccine Adjuvants for Multiple Types of Vaccines

Adjuvants are non-specific immune enhancers commonly used to improve the responsiveness and persistence of the immune system toward antigens. However, due to the undefined chemical structure, toxicity, non-biodegradability, and lack of design technology in many existing adjuvants, it remains difficult to achieve substantive breakthroughs in the adjuvant research field. Here, a novel adjuvant development strategy based on stapling peptides is reported to overcome this challenge. The nano-vaccine incorporating peptide adjuvant and recombinant HBsAg protein not only induced strong antibody titers that are equivalent to aluminum adjuvanted vaccines but also simultaneously activated T-cell immune response. Similar results are also observed in herpes zoster vaccine and more complex influenza vaccine. The mechanism analysis demonstrates that antigen is efficiently carried into antigen-presenting cells (APCs) by peptide, further promoting the secretion of cytokines and activation of APCs. In addition, by redesigning the adjuvant, it is found that the sulfonium centers, rather than the sequence of peptide played an important role in immune activation. This discovery may provide a new paradigm for the rational design of peptide-based adjuvants. In brief, this study demonstrates that stapling peptides with sulfonium centers can provide a well-defined, programmable, biocompatible, and effective adjuvant for multiple types of vaccines.

The Identification of Dual T-Cell and B-Cell Epitopes Within Viral Proteins Utilizing a Comprehensive Peptide Array Approach

Background/Objectives: The development of vaccines that elicit both T-cell and B-cell responses is crucial for effective immunity against pathogens. This study introduces a novel approach to identify precise epitope peptides within viral proteins that can stimulate both arms of the adaptive immune response, using Porcine Parvovirus (PPV) as a model. Methods: Mice were infected with PPV, and a peptide array was utilized to detect IgG signals in their sera. This approach facilitated the assessment of the immunogenicity of the PPV proteome, leading to the identification of 14 potential epitope candidates. These candidates were then used to immunize additional mice, and their ability to induce T-cell and B-cell responses was evaluated. Results: The immunization experiments identified an optimal peptide, P6, which robustly activated both T cells and B cells. Further analysis of the sub-regions of this peptide confirmed P6 as the most potent inducer of immune responses. The anticipated epitope was detected in mice immunized with P6, highlighting the efficacy of our method in identifying epitopes that engage both T cells and B cells. Conclusions: This study presents a novel strategy for the identification of dual T-cell and B-cell epitopes by directly evaluating the immunoreactivity of antibodies in serum. This finding holds significant promise for the advancement of epitope-based vaccines.

Contagious ecthyma in small ruminants: from etiology to vaccine challenges - a review

Orf virus (ORFV) is an epitheliotropic, double-stranded DNA pathogen belonging to the genus Parapoxvirus, and it is the causative agent of contagious ecthyma (CE) in small ruminants. It is an endemic disease on goat and sheep herds around the world. It is often a neglected disease, with impacts on herd health and productivity, while also being an occupational zoonosis. This review explores the causative agent of ovine ecthyma, its epidemiology, and clinical manifestations, with a particular emphasis on its interaction with the host's immune system and the development of ORFV vaccines. Like other members of the Poxviridae family, ORFV expresses numerous immunomodulatory genes, which complicate vaccination efforts and disease management. This review highlights the challenges posed by ORFV in achieving effective immunization and discusses potential vaccine strategies to overcome these obstacles.

Protection of Mice Vaccinated with a New B Cell and T Cell Epitopes Cocktail from Staphylococcus aureus Challenge in Skin Infection Model

Developing an effective vaccine against Staphylococcus aureus (S. aureus) is a key global health concern, especially with the increased reports of multidrug-resistant (MDR) S. aureus strains. Previous attempts for S. aureus vaccine development were unsuccessful. In this study, Manganese transport protein C (MABC) B cell epitopes, Nickel ABC transporter (NABC) B cell & T cell epitopes, and Phosphatidylinositol phosphodiesterase (PIc) B cell & T cell epitopes were used as a vaccine in mice skin infection model. Mice immunized with peptide mixture and MABC peptide group showed the best skin lesion healing results. The protection level was correlated with the highest IgG level, highest levels of interferon-gamma (INF γ), and lowest levels of interleukin-2 (IL-2). The peptide mixture group also showed the highest count of CD4/ CD8 cells. Results demonstrated that the inclusion of B cell and T cell epitopes of multiple genes improved both the humoral and cellular immunity and resulted in the best outcome in the skin infection mice model. A more expanded in-vivo study in different mice models is recommended for testing MABC, NABC, and PIc B cells and T cells peptides cocktail as promising S. aureus vaccine.

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.

Overview of Peptides and Their Potential Roles in Skin Health and Beauty

Peptides are molecules that consist of at least two amino acids linked by peptide bonds. The difference between peptides and proteins is primarily based on size and structure. Typically, oligopeptides consist of fewer than about 10-20 amino acids, and polypeptides consist of more than 20 amino acids, whereas proteins usually are made up more than 50 amino acids and often contain multiple peptide subunits as stated in the International Union of Pure and Applied Chemistry rules. Beyond the nutritional properties, peptides are also structural components of hormones, enzymes, toxins, and antibiotics and play several fundamental physiological roles in the body. Since the introduction of the first commercial peptide drug, insulin, peptide-based drugs have gained increased interest. So far, more than 80 peptide-based drugs have reached the market for a wide range of conditions, such as diabetes, cardiovascular diseases, and urological disorders. Meanwhile, peptides have also gained significant attention in the cosmetic industry because of their potential in boosting skin health. In this review, peptides were comprehensively summarized in the aspects of sources, function, the use of peptides in cosmetics and skin care, and indications for the delivery of cosmetic peptides.

Boosting CAR-T cell therapy through vaccine synergy

Chimeric antigen receptor (CAR)-T cell therapy has transformed the treatment landscape for hematological cancers. However, achieving comparable success in solid tumors remains challenging. Factors contributing to these limitations include the scarcity of tumor-specific antigens (TSAs), insufficient CAR-T cell infiltration, and the immunosuppressive tumor microenvironment (TME). Vaccine-based strategies are emerging as potential approaches to address these challenges, enhancing CAR-T cell expansion, persistence, and antitumor efficacy. In this review, we explore diverse vaccine modalities, including mRNA, peptide, viral vector, and dendritic cell (DC)-based vaccines, and their roles in augmenting CAR-T cell responses. Special focus is given to recent clinical advancements combining mRNA-based vaccines with CAR-T therapy for the treatment of genitourinary cancers. In addition, we discuss crucial considerations for optimizing vaccine dosing, scheduling, and delivery to maximize CAR-T synergy, aiming to refine this combination strategy to improve treatment efficacy and safety.

Peptides on patrol: Carrier systems for targeted delivery

The peptide is a small unit of protein that exhibits a diverse range of therapeutic applications, including but not limited to respiratory, inflammatory, oncologic, metabolic and neurological disorders. Peptides also play a significant role in signal transduction in cells. This chapter focuses on the delivery of peptides through the utilization of various carrier molecules, including liposomes, micelles, polymeric nanoparticles, and inorganic materials. These carriers facilitate targeted delivery and site-specific delivery of peptides. Different nanocarriers and therapeutic drug molecules also help with the delivery of peptides. Application to various diseases and different routes of delivery are described in this manuscript, along with current limitations and future prospects.

In silico design of a multi-epitope vaccine against Mycobacterium avium subspecies paratuberculosis

The widespread chronic enteritis known as Paratuberculosis (PTB) or Johne's disease (JD) is caused by Mycobacterium avium subspecies paratuberculosis (MAP), posing a significant threat to global public health. Given the challenges associated with PTB or JD, the development and application of vaccines are potentially important for disease control. The aim of this study was to design a multi-epitope vaccine against MAP. A total of 198 MAP genomes were analyzed using pan-genome and reverse vaccinology approaches. B-cell and T-cell epitope analysis was performed on the selected promising cross-protective antigens followed by selection of epitopes with high antigenicity, no allergenicity, and no toxicity for the design of the vaccine. The designed vaccine was evaluated through molecular dynamics simulations, molecular docking, and immunological simulations. The results revealed the identification of five promising cross-protective antigens. In total, 10 B-cell epitopes, 10 HTL epitopes, and 9 CTL epitopes were selected for the design of the vaccine. Both the vaccine candidate and the vaccine-TLR4 complex demonstrated considerable stability in molecular dynamics simulations. Molecular docking studies confirmed that the vaccine candidate successfully interacted with TLR4. Immunological simulations showed an increase in both B-cell and T-cell populations after vaccination. Additionally, the vaccine candidate exhibited a codon adaptability index of 1.0 and a GC content of 53.64%, indicating strong potential for successful expression in Escherichia coli. This research developed a multi-epitope vaccine targeting MAP through pan-genomes and reverse vaccinology methods, offering innovative strategies for creating effective vaccines against MAP.

A Self-Adjuvanting Large Pore 2D Covalent Organic Framework as a Vaccine Platform

Vaccines are one of the greatest human achievements in public health, as they help prevent the spread of diseases, reduce illness and death rates, saving thousands of lives with few side effects. Traditional vaccine development is centered around using live attenuated or inactivated pathogens, which is expensive and has resulted in vaccine-associated illnesses. Advancements have led to the development of safer subunit vaccines, which contain recombinant proteins isolated from pathogens. Their short half-life and small size make most subunit vaccines less immunogenic. Here, we introduce a large pore 2D covalent organic framework (COF), PyCOFamide, as a promising solution for an effective subunit platform. Our study demonstrates that simple adsorption of a model antigen, ovalbumin (OVA), onto PyCOFamide (OVA@COF) significantly enhances humoral and cell-mediated immune response compared to free OVA. OVA@COF exhibited heightened immune cell activation and acts as an antigen reservoir, facilitating antigen-presenting cell trafficking to the draining lymph nodes, amplifying the humoral immune response. Additionally, the breakdown of the COF releases monomers that adjuvant the activation of immune cells vital to creating strong immunity. This platform offers a potential avenue for safer, more effective subunit vaccines.

Gold Nanoparticles as a Platform for Delivery of Immunogenic Peptides to THP-1 Derived Macrophages: Insights into Nanotoxicity

BACKGROUND

Peptide-based nanovaccines have emerged as a promising strategy for combating infectious diseases, as they overcome the low immunogenicity that is inherent to short epitope-containing synthetic peptides. Gold nanoparticles (AuNPs) present several advantages as peptide nanocarriers, but a deeper understanding of the design criteria is paramount to accelerate the development of peptide-AuNPs nanoconjugates (p-AuNPs).

METHODS

Herein, we synthesized and characterized p-AuNPs of 23 nm (p-Au23) and 68 nm (p-Au68) with varying levels of peptide surface coverage and different peptide designs, investigating their effect on the cell viability (cell death and mitochondrial activity), cellular uptake, and cathepsin B activity in THP-1 macrophages.

RESULTS

p-Au23 proved no negative effect in the cell viability and high levels of nanoconjugate uptake, but p-Au68 induced strong toxicity to the cell line. The peptide sequences were successfully designed with spacer regions and a cell-penetrating peptide (pTAT) that enhanced cellular uptake and cathepsin B activity for p-Au23, while pTAT induced severe effects in the THP-1 viability (~40-60% cell death).

CONCLUSIONS

These findings provide valuable insight into the design criteria of AuNPs and immunogenic peptides, along with nanotoxicity effects associated with AuNP size and surface charge in human monocyte-derived macrophages.

Influenza A Virus H7 nanobody recognizes a conserved immunodominant epitope on hemagglutinin head and confers heterosubtypic protection

Influenza remains a persistent global health challenge, largely due to the virus' continuous antigenic drift and occasional shift, which impede the development of a universal vaccine. To address this, the identification of broadly neutralizing antibodies and their epitopes is crucial. Nanobodies, with their unique characteristics and binding capacity, offer a promising avenue to identify such epitopes. Here, we isolate and purify a hemagglutinin (HA)-specific nanobody that recognizes an H7 subtype of influenza A virus. The nanobody, named E10, exhibits broad-spectrum binding, cross-group neutralization and in vivo protection across various influenza A subtypes. Through phage display and in vitro characterization, we demonstrate that E10 specifically targets an epitope on HA head which is part of the conserved lateral patch and is highly immunodominant upon H7 infection. Importantly, immunization with a peptide including the E10 epitope elicits cross-reactive antibodies and mediates partial protection from lethal viral challenge. Our data highlights the potential of E10 and its associated epitope as a candidate for future influenza prevention strategies.

Advancing novel veterinary vaccines: From comprehensive antigen and adjuvant design to preparation process optimization

Vaccination stands as the paramount and cost-effective strategy for the prevention and management of animal infectious diseases. With the advances in biological technology, materials science and industrial optimization, substantial progress has been made in the development of innovative veterinary vaccines. A majority of the novel vaccines under current investigation tend to stimulate multiple immune pathways and to achieve long-term resistance against infectious diseases, yet it remains imperative to concentrate research efforts on the efficient utilization of vaccines, mitigating toxic side effects, and ensuring safe production processes. This article presents an overview of research progress in veterinary vaccines, encompassing comprehensive antigen design, adjuvant formulation advancements, preparation process optimization, and rigorous immune efficacy evaluation. It summarizes cutting-edge vaccines derived from in vitro synthesis and in vivo application, emphasizing immunogenic components and immune response mechanisms. It also highlights novel biological adjuvants that enhance immune efficacy, diversify raw materials, and possess targeted functions, while comprehensively exploring advancements in production methodologies and compatible vaccine products. By establishing a foundation for the integrated use of these innovative veterinary vaccines, this work facilitates future interdisciplinary cooperation in their advancement, aiming to accelerate the achievement of herd immunity through concerted efforts.

Establishment of a novel tumor neoantigen prediction tool for personalized vaccine design

The personalized neoantigen nanovaccine (PNVAC) platform for patients with gastric cancer we established previously exhibited promising anti-tumor immunoreaction. However, limited by the ability of traditional neoantigen prediction tools, a portion of epitopes failed to induce specific immune response. In order to filter out more neoantigens to optimize our PNVAC platform, we develop a novel neoantigen prediction model, NUCC. This prediction tool trained through a deep learning approach exhibits better neoantigen prediction performance than other prediction tools, not only in two independent epitope datasets, but also in a totally new epitope dataset we construct from scratch, including 25 patients with advance gastric cancer and 150 candidate mutant peptides, 13 of which prove to be neoantigen by immunogenicity test in vitro. Our work lay the foundation for the improvement of our PNVAC platform for gastric cancer in the future.

FGL2172-220 peptides improve the antitumor effect of HCMV-IE1mut vaccine against glioblastoma by modulating immunosuppressive cells in the tumor microenvironment

Glioblastoma multiforme (GBM) is a highly aggressive primary brain tumor characterized by poor prognosis and lack of effective treatments. In recent years, peptide vaccines that use sequences based on tumor-specific or tumor-associated antigens to activate immune responses against tumor cells have emerged as a new therapeutic strategy. In this study, we developed a novel therapeutic polypeptide vaccine targeting the tumor-associated antigen Fibrinogen-Like Protein 2 (FGL2), whose dominant epitope peptide was tandemly linked to the C-terminus of HCMV-IE1mut via a linker. We used this vaccine to compare the therapeutic efficacy of HCMV-IE1mut alone versus HCMV-IE1mut-FGL2172-220 and investigate the potential mechanism of action of HCMV-IE1mut-FGL2172-220 in glioma treatment. An in situ GBM model (GL261-IE1-luc cells) was used to determine the efficacy of the vaccine. Treatment with HCMV-IE1mut-FGL2172-220 exerted antitumor effects and extended the survival of the GL261 animal model. We observed reduced proportions of microglia, regulatory T cells (Treg), and myeloid-derived suppressor cells (MDSC) in the tumor microenvironment (TME) by immunofluorescence. Flow cytometry showed that compared to HCMV-IE1mut alone, treatment with HCMV-IE1mut-FGL2172-220 increased the proportion of CD8+ T cells and tissue-resident memory T cells (TRM). ELISA analysis showed that it improved the secretion of tumor-specific IFN-γ and TNF-α by these cells and downregulated the expression of IL-6 and IL-10. Our study demonstrates that the long-peptide FGL2172-220 improves the antitumor efficacy of HCMV-IE1mut, possibly by reshaping immune cells in the glioma microenvironment. These findings lay the groundwork for the development of therapeutic antigenic peptide vaccines to improve antitumor effects for cancer.

A SARS-CoV-2 peptide antigen purified from bacteria and displayed in a high-density repetitive manner on a virus-like particle could generate anti-SARS-CoV-2 neutralizing antibodies unlike free peptide

SARS-CoV-2 is an enveloped virus. Proteins of the lipid based envelope are not rigidly arranged as compared to non-enveloped viruses lacking lipid based outer layer. Rigidly arranged multivalent display has been reported to be important for potent immune stimulation. We assembled himeric virus-like-particle (VLP) where the core of the particle is composed of the coat protein of Acinetobacter phage. Peptide-based antigen from receptor binding domain (RBD) of SARS-CoV-2 spike protein has been displayed on the coat based VLP matrix using spy-tag/spy-catcher split inteine conjugation system that allows spontaneous, irreversible isopeptide bond formation. Both the matrix as well as peptide have been purified from bacteria which is an easy platform for protein purification. We used the closed state of spike trimer for epitope mapping as this is the conformation of the spike that the immune system visualizes unlike the open state that appears when the virus tries to attach to receptor. Mice based immunization studies were used to test immunogenicity of the antigens. The work demonstrates that peptide-based antigens displayed in high densities can induce neutralizing antibody production unlike free peptide. Careful choice of peptides can deliver better candidates. Also, small size allows easy improvisation. Production in bacteria offers cheaper and robust purification option.

A Universal Multi-Epitope Vaccine Design Against Porcine Reproductive and Respiratory Syndrome Virus via Bioinformatics and Immunoinformatics Approaches

Porcine reproductive and respiratory syndrome virus (PRRSV) causes reproductive disorders in sows and severe pneumonia in piglets, alongside immunosuppressive effects on the host. It poses a significant global threat to the swine industry, with no effective control measures currently available due to its complex pathogenesis and high variability. Conventional inactivated and attenuated vaccines provide inadequate protection and carry biosafety risks. In this study, we designed a universal multi-epitope peptide vaccine against PRRSV using bioinformatics and immunoinformatics approaches to address these limitations. By selecting sequences from seven representative PRRSV strains, we predicted highly conserved and immunogenic T cell (Th and CTL) epitopes across all encoded proteins. These were rationally concatenated with reported B cell neutralizing epitopes into a multi-epitope vaccine construct. We performed comprehensive assessments of the construct's physicochemical and biochemical properties, along with predictions and refinements of its secondary and tertiary structures. Molecular docking simulations with TLR2 and TLR4 revealed strong potential binding interactions. Immune simulations indicated that the multi-epitope vaccine could induce robust humoral and cellular immune responses. This study provides a scientific foundation for the development of safe and effective PRRSV subunit vaccines and offers new perspectives for designing vaccines against other viral diseases.

A recent perspective on designing tumor vaccines for tumor immunology

With the rapid development of immunotherapy, therapeutic tumor vaccines, which aim to enhance the immunogenicity of tumor cells and activate the patient's immune system to kill tumor cells, as well as eliminate or inhibit tumor growth, have drawn increasing attention in the field of tumor therapy. However, due to the lack of immune cell infiltration, low immunogenicity, immune escape and other problems, the efficacy of tumor vaccine is often limited. Researchers have developed a variety of strategies to enhance tumor immune recognition, such as improving the immunogenicity of tumor antigens, selecting a suitable vaccine platform, or combining tumor vaccines with other anticancer treatments. In this review, we will deliberate on how to overcome the problem of therapeutic tumor vaccines, and discuss the up-to-date progress and achievements in the tumor vaccine development, as well as their future in cancer treatment.

Chikungunya virus E2 B domain nanoparticle immunogen elicits homotypic neutralizing antibody in mice

Alphaviruses are enveloped, positive-sense single-stranded RNA viruses that cause severe human and animal illness. Arthritogenic alphaviruses, such as Chikungunya virus (CHIKV) and Mayaro virus (MAYV), are globally distributed, transmitted by mosquitoes, and can cause rheumatic disease characterized by fever, rash, myalgia, and peripheral polyarthralgia that can persist for years post-infection. These infections can also result in more severe clinical manifestations such as hemorrhage, encephalopathy, and mortality. Several potent monoclonal antibodies (mAbs) with broad neutralizing activity have been shown to bind to the E2 B domain (E2-B) of the alphavirus glycoprotein, suggesting that E2-B epitopes are a site of susceptibility for multiple arthritogenic alphaviruses. However, it is unknown whether E2-B alone can elicit a broadly neutralizing humoral response. Here, we generate and characterize nanoparticle-based immunogens containing CHIKV and MAYV E2-B. Immunization with the CHIKV E2-B nanoparticle elicited sera that were cross-reactive toward CHIKV and MAYV E2-B, but had only homotypic neutralizing activity (serum titer of 1:512) against CHIKV vaccine strain 181/25. Furthermore, immunization with MAYV E2-B nanoparticles elicited non-neutralizing antibody, but sera were cross-reactive for both CHIKV and MAYV E2-B. Our findings suggest that the immunodominant epitopes within CHIKV and MAYV E2-B are bound by cross-reactive, but not cross-neutralizing antibody. Therefore, development of broad E2-B based vaccines that induce broadly neutralizing antibody responses will require engineering to alter the immunodominant landscape.

Challenges and considerations in multi-epitope vaccine design surrounding toll-like receptors

Epitope-based peptide vaccines elicit targeted immune responses, making them effective for diseases requiring focused immune activation, such as targeting cancer-associated antigens. Strategies like peptide cocktails and mRNA-based epitope vaccines have revolutionized the field; however, the term 'multi-epitope peptide vaccine' has been overextended, especially concerning the use of toll-like receptors (TLRs), their ligands, and peptide linkers. TLRs are often conflated with T cell receptors (TCRs) and B cell receptors (BCRs), which recognize immunogenic peptides within vaccines. This Opinion clarifies the role of TLRs and highlights challenges linked to their indiscriminate use in multi-epitope vaccine design. While peptide linkers are crucial in creating multivalent vaccines, their unsupervised application is increasing and warrants attention. After highlighting their role in advancing peptide vaccines, we discuss critical factors in linker implementation and caution against their misuse, which could undermine vaccines' efficacy.

Peptide-based therapeutics targeting genetic disorders

Genetic disorders (GDs) are challenging to treat owing to a lack of optimal treatment regimens and intricate and often difficult-to-understand underlying biological processes. Limited therapeutic approaches, which mostly provide symptomatic relief, are available. To date, a limited number of peptide-based drugs for the treatment of GDs are available, and several candidates are under clinical study. This review provides mechanistic insights into GDs and potential target areas where peptide-based drugs are beneficial. In addition, it emphasizes the usefulness of peptides as carriers for gene delivery, biomarkers for mutation detection and peptide-based vaccines for treating GDs.

Immunoinformatic approach to the design of a novel multi-epitope vaccine against Leishmania major fused to human IgG-Fc

Background and purpose

Cutaneous leishmaniasis poses significant health and socioeconomic challenges, making vaccine development a top priority, especially in endemic regions. Cysteine proteases, KMP-11, and HASPB proteins are promising candidates for leishmaniasis vaccine development owing to their immunogenic properties and capacity to provoke robust immune responses, as evidenced by different investigations. This study aimed to design a recombinant chimeric protein (MEV-Fc) vaccine using multi-epitopes from these Leishmania major proteins.

Experimental approach

The antigens were subjected to immunoinformatic prediction and screening of HTL, CTL, and B-cell epitopes. The multi-epitope protein was designed with significantly high-scoring epitopes and suitable linkers. Natural adjuvants were then added to enhance immunogenicity. Vaccine potency was innovatively improved by covalently fusing human IgG1 Fc with multi-epitope protein. To investigate how the MEV-Fc vaccine interacts with Toll-like receptors, molecular docking, multi-scale normal mode analysis simulation, and computational immune simulation were employed to study humoral and cellular immune responses.

Findings/Results

The results demonstrated the vaccine's antigenicity, stability, and nontoxicity. The structural validation confirmed the accuracy of the 3D models, indicating robust interactions with TLR2 and TLR4, with binding free energies of -1269.9 and -1128.7 (kcal/mol), respectively. Immune simulation results showed significant increases in IgM and IgG antibody levels following three vaccinations, along with enhanced activation of B cells, helper T cells, and cytotoxic T lymphocytes.

Conclusion and implications

These findings provide novel insights for developing effective candidates for cutaneous leishmaniasis vaccines. However, laboratory experiments are necessary to evaluate its protective effects.

A novel pan-epitope based nanovaccine self-assembled with CpG enhances immune responses against flavivirus

BACKGROUND

Flavivirus is a highly prevalent and outbreak-prone disease, affecting billions of individuals annually and posing substantial public health challenges. Vaccination is critical to reducing the global impact of flavivirus infections, making the development of a safe and effective vaccine a top priority. The self-assembled pan-epitope vaccine presents key advantages for improving immunogenicity and safety without relying on external vectors or adding immunomodulatory elements, both of which are essential for successful vaccine development.

RESULTS

In this study, the pan-epitope peptide TBT was combined with adjuvant CpG to form the TBT-CpG nanovaccine (TBT-CpG NaVs), which was found to be spherical, uniform in shape, and demonstrated strong serum stability. In vitro studies showed that the TBT-CpG NaVs were efficiently taken up and internalized by bone marrow-derived dendritic cells (BMDCs). Flow cytometry and transcriptomic analysis indicated that the antigens were effectively presented to antigen-presenting cells (APCs) via the MHC II pathway, which facilitated BMDCs maturation and promoted the release of pro-inflammatory cytokines IL-1β, TNF-α, and IL-6. In vivo studies confirmed that TBT-CpG NaVs enhanced antigen-specific IgG levels, significantly increased IFN-γ and IL-4 expression in spleen cells, and offered protective effects against Dengue virus (DENV) and Zika virus (ZIKV) infections. Safety evaluations revealed no hepatotoxicity and no significant organ damage in immunized mice.

CONCLUSION

The self-assembled candidate nanovaccine TBT-CpG NaVs effectively activates BMDCs and triggers a targeted immune response, providing antiviral effects against DENV and ZIKV. This vaccine demonstrates good immunogenicity and safety, establishing a promising foundation and a new strategy for the development of safe and effective vaccines.

Non-RBD peptides of SARS-CoV-2 spike protein exhibit immunodominance as they elicit both innate and adaptive immune responses

Severe acute respiratory coronavirus-2 (SARS-CoV-2) emerged in 2019 as a new virus and caused worldwide outbreaks, quickly turning into a pandemic disease called coronavirus disease-19 (COVID-19). All the existing methodologies were used for developing vaccines for this virus. But sporadic infections of this virus and the emergence of new strains to date suggest the incomplete protection offered by the developed vaccines and the need for new research. In this direction, we identified five epitopes present in the non-RBD region and on the surface of the spike protein by in silico analysis. They are epitope I (aa 80-90), epitope II (aa 262-270), and a small protein with three epitopes (aa 1059-1124). Antigenicity scores of these epitopes were found to be higher than the full length spike protein and its RBD region. These epitopes showed high conserveness across the emerging strains, high immunogenicity, non-toxicity, no homology with human sequences and high affinity for MHC class I & II molecules. Antibodies raised against these epitopes interacted with the bacterially expressed spike protein in western blotting. The antiserum of COVID-19 recovered participants reacted with the developed epitopes (small protein). Furthermore, in the presence of the respective antiserum and COVID-19 convalescent serum, these epitopes successfully fixed the complement, implying a possible role in innate immunity. The epitopes were also found to activate the peripheral blood mononuclear cells (PBMCs) isolated from the blood samples of COVID-19 recovered/vaccinated participants, suggesting a possible role in adaptive immunity. The need for the new SARS-CoV-2 vaccines is further highlighted in light of current reports about the side effects of a developed vaccine (AstraZeneca) and the circulating new strains. The epitopes presented in this study represent the potential immunogens and expect certain pitfalls of the existing vaccines would be sealed.

Irradiated whole cell Chlamydia vaccine confers significant protection in a murine genital tract challenge model

Chlamydia trachomatis infections are the most common bacterial STIs globally and can lead to serious morbidity if untreated. Development of a killed, whole-cell vaccine has been stymied by coincident epitope destruction during inactivation. Here, we present a prototype Chlamydia vaccine composed of elementary bodies (EBs) from the related mouse pathogen, Chlamydia muridarum (Cm). EBs inactivated by gamma rays (Ir-Cm) in the presence of the antioxidant Mn2+-Decapeptide (DEHGTAVMLK) Phosphate (MDP) are protected from epitope damage but not DNA damage. Cm EBs gamma-inactivated with MDP retain their structure and provide significant protection in a murine genital tract infection model. Mice vaccinated with Ir-Cm (+MDP) exhibited elevated levels of Cm-specific IgG and IgA antibodies, reduced bacterial burdens, accelerated clearance, and distinctive cytokine responses compared to unvaccinated controls and animals vaccinated with EBs irradiated without MDP. Preserving EB epitopes with MDP during gamma inactivation offers the potential for a polyvalent, whole-cell vaccine against C. trachomatis.

Personalized cancer vaccine design using AI-powered technologies

Immunotherapy has ushered in a new era of cancer treatment, yet cancer remains a leading cause of global mortality. Among various therapeutic strategies, cancer vaccines have shown promise by activating the immune system to specifically target cancer cells. While current cancer vaccines are primarily prophylactic, advancements in targeting tumor-associated antigens (TAAs) and neoantigens have paved the way for therapeutic vaccines. The integration of artificial intelligence (AI) into cancer vaccine development is revolutionizing the field by enhancing various aspect of design and delivery. This review explores how AI facilitates precise epitope design, optimizes mRNA and DNA vaccine instructions, and enables personalized vaccine strategies by predicting patient responses. By utilizing AI technologies, researchers can navigate complex biological datasets and uncover novel therapeutic targets, thereby improving the precision and efficacy of cancer vaccines. Despite the promise of AI-powered cancer vaccines, significant challenges remain, such as tumor heterogeneity and genetic variability, which can limit the effectiveness of neoantigen prediction. Moreover, ethical and regulatory concerns surrounding data privacy and algorithmic bias must be addressed to ensure responsible AI deployment. The future of cancer vaccine development lies in the seamless integration of AI to create personalized immunotherapies that offer targeted and effective cancer treatments. This review underscores the importance of interdisciplinary collaboration and innovation in overcoming these challenges and advancing cancer vaccine development.

Folate Receptor Alpha-A Secret Weapon in Ovarian Cancer Treatment?

Epithelial ovarian cancer (EOC) is the most lethal gynecological malignancy worldwide. Due to its nonspecific symptoms and unreliable screening tools, EOC is not diagnosed at an early stage in most cases. Unfortunately, despite achieving initial remission after debulking surgery and platinum-based chemotherapy, most patients experience the recurrence of the disease. The limited therapy approaches have encouraged scientists to search for new detection and therapeutic strategies. In this review, we discuss the role of folate receptor alpha (FRα) in EOC development and its potential application as a biomarker and molecular target in designing new EOC screening and treatment methods. We summarize the mechanisms of the action of various therapeutic strategies based on FRα, including MABs (monoclonal antibodies), ADCs (antibody-drug conjugates), FDCs (folate-drug conjugates), SMDCs (small molecule-drug conjugates), vaccines, and CAR-T (chimeric antigen receptor T) cells, and present the most significant clinical trials of some FRα-based drugs. Furthermore, we discuss the pros and cons of different FR-based therapies, highlighting mirvetuximab soravtansine (MIRV) as the currently most promising EOC-targeting drug.

Development of Self-Adjuvants in mRNA Vaccine and Its Application in Disease Prevention and Treatment

Adjuvants augment the immunogenicity of vaccines when co-administered with messenger RNA (mRNA) antigens. In recent years, nanotechnology and nanoscience have seen significant growth, resulting in the discovery of synthetic small molecule compounds, natural extracts, and nanomaterials with self-adjuvant properties for nano delivery. The materials exhibit robust immune activity and efficiently activate various innate immune signaling pathways. Moreover, they possess a comparatively simple chemical composition in contrast to conventional adjuvants. This significantly streamlines the manufacturing process of vaccine formulations. Therefore, these self-adjuvant materials theoretically improve the reproducibility of adjuvant production and quality control. Herein, this review summarizes the current research and development progress of mRNA adjuvants, with a specific focus on various types of mRNA adjuvants, notably self-adjuvant nanomaterials. It discusses the current research status on a range of diseases and investigates the potential development of mRNA vaccine adjuvants.