Approved Vaccine Research Articles

One-year follow-up evaluation of approved Subolesin anti-tick vaccine in Uganda

After approval of the Subolesin-based anti-tick vaccine in Uganda, we completed a one-year follow-up evaluation study. The results showed significantly 2.1–5.0-fold higher anti-SUB IgG antibody titers in vaccinated cattle in Mbarara and Maruzi with vaccine effectiveness higher than 95 %. In Mbarara, total number of ticks were 0.8-fold lower in vaccinated cattle with a negative correlation tendency between anti-SUB antibody titers and tick counts. The CCHFV-seropositive cattle significantly decreased in 40 % in SUB-vaccinated animals with a significant positive correlation between CCHFV-seropositive cattle and the total number of ticks per animal and a negative correlation tendency between anti-SUB antibody titers and CCHFV-seropositive cattle. A boosting vaccine dose yearly after primary vaccination with three doses is sufficient to maintain protective antibody titers against ticks and tick-borne diseases affecting human and animal health. These results are relevant for implementation of anti-tick Subolesin-based vaccines in Uganda and other countries in Sub-Saharan Africa.

Construction and evaluation of glycoprotein-based nucleic acid vaccines for Marburg virus.

Marburg virus (MARV) is a zoonotic virus that can infect humans and non-human primates (NHPs) and lead to a fatal Marburg hemorrhagic fever (MHF), while there is no approved vaccine or antiviral treatment for MHF. The nucleic acid vaccine has unique advantages, including fast and simple preparation, easy to follow the virus mutation situation, and less adverse reactions. Therefore, we constructed the DNA and mRNA candidate vaccines based on codon-optimized MARV glycoprotein sequence, and evaluated the immune effect in mice through ELISA, ELISpot, and Flow cytometry. After the second booster immunization, both of the candidate vaccines induced strong humoral immune response, enhanced T cell response, and elicited neutralizing antibodies. Notably, DNA candidate vaccine induced stronger humoral immune response, while mRNA candidate vaccine elicited higher levels of IFN-γ and IL-4. In addition, transcriptome analysis revealed that the candidate vaccines activated immune response related pathways. Our study shed new light on the nucleic acid vaccines for MARV and further confirmed the potential of nucleic acid vaccine for future MHF prevention and control.

Seoul orthohantavirus evades innate immune activation by reservoir endothelial cells

Seoul orthohantavirus evades innate immune activation by reservoir endothelial cells

Backstage Heroes—Yeast in COVID-19 Research

The extremely rapid development of understanding and technology that led to the containment of the COVID-19 pandemic resulted from collaborative efforts in the fields of Betacoronavirus pandemicum (SARS-CoV-2) biology, pharmacology, vaccinology, and medicine. Perhaps surprisingly, much of the research was conducted using simple and efficient yeast models. In this manuscript, we describe how yeast, eukaryotic microorganisms, have been used to research this global challenge, focusing on the therapeutic potential of the studies discussed herein. Thus, we outline the role of yeast in studying viral protein interactions with the host cell proteome, including the binding of the SARS-CoV-2 virus spike protein to the human ACE2 receptor and its modulation. The production and exploration of viral antigens in yeast systems, which led to the development of two approved COVID-19 vaccines, are also detailed. Moreover, yeast platforms facilitating the discovery and production of single-domain antibodies (nanobodies) against SARS-CoV-2 are described. Methods guiding modern and efficient drug discovery are explained at length. In particular, we focus on studies designed to search for inhibitors of the main protease (Mpro), a unique target for anti-coronaviral therapies. We highlight the adaptability of the techniques used, providing opportunities for rapid modification and implementation alongside the evolution of the SARS-CoV-2 virus. Approaches introduced in yeast systems that may have universal potential application in studies of emerging viral diseases are also described.

Zika virus remodels and hijacks IGF2BP2 ribonucleoprotein complex to promote viral replication organelle biogenesis.

Zika virus (ZIKV) infection causes significant human disease that, with no approved treatment or vaccine, constitutes a major public health concern. Its life cycle entirely relies on the cytoplasmic fate of the viral RNA genome (vRNA) through a fine-tuned equilibrium between vRNA translation, replication, and packaging into new virions, all within virus-induced replication organelles (vROs). In this study, with an RNA interference (RNAi) mini-screening and subsequent functional characterization, we have identified insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) as a new host dependency factor that regulates vRNA synthesis. In infected cells, IGF2BP2 associates with viral NS5 polymerase and redistributes to the perinuclear viral replication compartment. Combined fluorescence in situ hybridization-based confocal imaging, in vitro binding assays, and immunoprecipitation coupled to RT-qPCR showed that IGF2BP2 directly interacts with ZIKV vRNA 3' nontranslated region. Using ZIKV sub-genomic replicons and a replication-independent vRO induction system, we demonstrated that IGF2BP2 knockdown impairs de novo vRO biogenesis and, consistently, vRNA synthesis. Finally, the analysis of immunopurified IGF2BP2 complex using quantitative mass spectrometry and RT-qPCR revealed that ZIKV infection alters the protein and RNA interactomes of IGF2BP2. Altogether, our data support that ZIKV hijacks and remodels the IGF2BP2 ribonucleoprotein complex to regulate vRO biogenesis and vRNA neosynthesis.

Zika virus remodels and hijacks IGF2BP2 ribonucleoprotein complex to promote viral replication organelle biogenesis

Zika virus (ZIKV) infection causes significant human disease that, with no approved treatment or vaccine, constitutes a major public health concern. Its life cycle entirely relies on the cytoplasmic fate of the viral RNA genome (vRNA) through a fine-tuned equilibrium between vRNA translation, replication, and packaging into new virions, all within virus-induced replication organelles (vROs). In this study, with an RNA interference (RNAi) mini-screening and subsequent functional characterization, we have identified insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) as a new host dependency factor that regulates vRNA synthesis. In infected cells, IGF2BP2 associates with viral NS5 polymerase and redistributes to the perinuclear viral replication compartment. Combined fluorescence in situ hybridization-based confocal imaging, in vitro binding assays, and immunoprecipitation coupled to RT-qPCR showed that IGF2BP2 directly interacts with ZIKV vRNA 3’ nontranslated region. Using ZIKV sub-genomic replicons and a replication-independent vRO induction system, we demonstrated that IGF2BP2 knockdown impairs de novo vRO biogenesis and, consistently, vRNA synthesis. Finally, the analysis of immunopurified IGF2BP2 complex using quantitative mass spectrometry and RT-qPCR revealed that ZIKV infection alters the protein and RNA interactomes of IGF2BP2. Altogether, our data support that ZIKV hijacks and remodels the IGF2BP2 ribonucleoprotein complex to regulate vRO biogenesis and vRNA neosynthesis.

MiRNA-431-5p enriched in EVs derived from IFN-β stimulated MSCs potently inhibited ZIKV through CD95 downregulation

BackgroundZika virus (ZIKV) primarily spreads through mosquito bites and can lead to microcephaly in infants and Guillain-Barre syndrome in adults. It is noteworthy that ZIKV can persist in the semen of infected males for extended periods and can be sexually transmitted. Infection with ZIKV has severe pathological manifestations on the testicular tissues of male mice, resulting in reduced sperm motility and fertility. However, there are no approved prophylactic vaccines or therapeutics available to treat Zika virus infection.MethodsUsing a male type I and II interferon receptor-deficient (ifnar1(-/-) ifngr1(-/-)) C57BL/6 (AG6) mouse model infected with ZIKV as a representative model, we evaluated the degree of testicular damage and viral replication in various organs in mice treated with EVs derived from MSC-stimulated with IFN-β (IFNβ-EVs) and treated with controls. We measured testicle size, detected viral load in various organs, and analyzed gene expression to assess treatment efficacy.ResultsOur findings demonstrated that intravenous administration of IFNβ-EVs effectively suppressed ZIKV replication in the testes. Investigation with in-depth RNA sequencing analysis found that IFN-β treatment changed the cargo miRNA of EVs. Notably, miR-431-5p was identified to be significantly enriched in IFNβ-EVs and exhibited potent antiviral activity in vitro. We showed that CD95 was a direct downstream target for miR-431-5p and played a role in facilitating ZIKV replication. miR-431-5p effectively downregulated the expression of CD95 protein, consequently promoted the phosphorylation and nuclear localization of NF-kB, which resulted in the activation of anti-viral status, leading to the suppression of viral replication.ConclusionsOur study demonstrated that the EVs produced by IFNβ-treated MSCs could effectively convey antiviral activity.

A Lassa virus live attenuated vaccine candidate that is safe and efficacious in guinea pigs

Lassa virus (LASV) is a rodent-borne mammarenavirus that causes tens to hundreds of thousands of human infections annually in Western Africa. Approximately 20% of these infections progress to Lassa fever (LF), an acute disease with case–fatality rates from ≈20–70%. Currently, there are no approved vaccines or specific therapeutics to prevent or treat LF. The LASV genome consists of a small (S) segment that has two genes, GP and NP, and a large (L) segment that has two genes, L and Z. In both segments, the two genes are separated by non-coding intergenic regions (IGRs). Recombinant LASVs (rLASVs), in which the L segment IGR was replaced with the S segment IGR or in which the GP gene was codon-deoptimized, lost fitness in vitro, were highly attenuated in vivo, and, when used as vaccines, protected domesticated guinea pigs from otherwise lethal LASV exposure. Here, we report the generation of rLASV/IGR-CD, which includes both determinants of attenuation and further enhances the safety of the vaccine compared with its predecessors. rLASV/IGR-CD grew to high titers in Vero cells, which are approved for human vaccine production, but did not cause signs of disease or pathology in guinea pigs. Importantly, guinea pigs vaccinated with rLASV/IGR-CD were completely protected from disease and death after a typically lethal exposure to wild-type LASV. Our data support the development of rLASV/IGR-CD as a live-attenuated LF vaccine with stringent safety features.

Does Policy Uncertainty Boost Vaccine Hesitancy? Political Controversy, the FDA and COVID-19 Vaccine Hesitancy in Fall 2020.

Vaccine hesitancy is associated with political and institutional distrust, but there is little research on how people's trust responds to political events. We revisit the fall of 2020 when evaluation of new COVID-19 vaccines collided with an impending national election. Drawing on a political Bayesian perspective, we assess abrupt changes in attention to political events and test hypotheses on subpopulation response: (1) partisan, (2) educational, and (3) ethnic and racial. Analysis of daily changes in news reporting and social media use in 2020, combined with detailed analysis of two-large scale surveys fielded at the time, focusing on questions of COVID-19 vaccine hesitancy and safety concerns about COVID-19 vaccines. Vaccine hesitancy in the US spiked from late August to early October 2020. We identify several plausible triggers for this spike, all pertaining to the FDA and electoral politics. Heightened vaccine hesitancy occurred among Democrats, Asian and Black citizens, as well as college-educated respondents. Turbulence mainly affected those who were initially most trusting in government and vaccines. Asian-American vaccine confidence recovered; that of Black Americans did not. Electoral politics may destabilize citizen assumptions about vaccine authorization and boost uncertainty, thereby undermining public willingness to take approved vaccines.

Protective threshold of a potent neutralizing Zika virus monoclonal antibody in rhesus macaques.

Zika virus (ZIKV) is a mosquito-borne flavivirus that caused a global pandemic in 2016-2017 with continued ongoing transmission at low levels in several countries. In the absence of an approved ZIKV vaccine, neutralizing monoclonal antibodies (mAbs) provide an option for the prevention and treatment of ZIKV infection. Previous studies identified a potent neutralizing human mAb ZIKV-117 that reduced fetal infection and death in mice following ZIKV challenge. In this study, we report exquisite potency of ZIKV-117-LALA-YTE, which has been engineered to reduce Fc receptor binding and to extend half-life, in a titration study in rhesus macaques to protect against ZIKV challenge. We show complete protection at a dose of 0.016 mg/kg ZIKV-117-LALA-YTE, which resulted in median serum concentrations of 0.13 µg/mL. The high potency of this mAb supports its potential clinical development as a novel biotherapeutic intervention for ZIKV.IMPORTANCEIn this study, we report the potency of the Zika virus (ZIKV)-specific neutralizing antibody ZIKV-117-LALA-YTE against ZIKV challenge in a titration study rhesus macaques. This high potency supports the further development of this monoclonal antibody for ZIKV.

Does Experience of Vaccination Improve Vaccine Confidence and Trust? Policy Feedback Effects of Mass COVID-19 Vaccination in the United States.

Policy feedback research has demonstrated that a highly tangible policy that shapes public attitudes through direct and day-to-day experiences often reshapes public opinion, with the effect of generating supportive or skeptical constituencies that determine the sustainability of future programs. This paper examines the impact of mass vaccination efforts on attitudes towards vaccines in a context of high vaccine hesitancy in the U.S. We analyzed 73,092 survey responses from 9,229 participants in the longitudinal data from the Understanding America Study project, covering December 2020 to July 2023. Using two-way fixed-effects ordinary least squares regression and ordinal logistic regression, we estimated the changes in attitudes towards vaccines, including trust in vaccine manufacturing and approval processes, following COVID-19 vaccinations. COVID-19 vaccination was associated with improved perceptions of vaccine effectiveness and social benefits and reduced mistrust in vaccine-related processes. However, it did not significantly alleviate concerns regarding vaccine side effects and illness. The strongest effects were observed among respondents initially hesitant but who eventually vaccinated. The experience of COVID-19 vaccination generally improved attitudes and confidence in COVID-19 vaccines among the U.S. public, particularly among vaccine-hesitant people. These effects could have positive impacts on future immunization programs by mitigating vaccine hesitancy.

Abstract PR007: To the tumor and beyond: Tales of a holistic miRNA delivery vehicle

Abstract Like the challenges and skepticism that faced the antibody therapeutics field over a decade ago, RNA therapeutics is facing the same. And, like the antibody therapeutics field, we are beginning to realize the clinical impact of RNA therapeutics amiss these challenges. This is most clearly highlighted with the recent approval of mRNA vaccines and RNAi drugs targeted to the liver. Unfortunately, RNA-based drugs targeted to tumors is lagging behind, even with countless years of work that has revealed the power of using RNAi for treating oncological diseases. Lack of success is attributed to inability to deliver RNAi safely and effectively. A successful delivery agent requires multiple features. First, the agent must deliver the RNA specifically to the intended cells. Second, the agent must have a large therapeutic window, meaning that toxicity, if observed, should occur at doses that are orders of magnitude higher than the therapeutic dose. Third, if delivery of the RNA is by way of a specific ligand and receptor pair, as is the case herein, the RNA must successfully escape the endosome. Simply swelling the endosome is not enough if noncovalent interactions between the ligand and the receptor cannot be disrupted. Fourth, the RNA should include appropriate stabilizing modifications to increase intracellular half-life that will reduce dosing and cost. Through hard work and dedication, we have come up with an inclusive, easily synthesized, intramolecular molecule that achieves all of these essential features. Here, the challenges we face, the hurdles we have overcome, and the barriers that still remain with achieving success in reveling the clinical potential of miRNAs as anti-cancer therapeutics will be presented. Citation Format: Andrea L Kasinski. To the tumor and beyond: Tales of a holistic miRNA delivery vehicle [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: RNAs as Drivers, Targets, and Therapeutics in Cancer; 2024 Nov 14-17; Bellevue, Washington. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(11_Suppl):Abstract nr PR007.

The herpes simplex virus alkaline nuclease is required to maintain replication fork progression.

Herpes simplex virus 1 (HSV-1) is a near-ubiquitous pathogen within the global population, causing a lifelong latent infection with sporadic reactivation throughout the life of the host. Within at-risk and immunocompromised communities, HSV-1 infection can cause serious morbidities including herpes keratitis and encephalitis. With the possibility of herpesviruses to evade established antiviral therapies and there being no approved HSV-1 vaccine, there comes a need to investigate potential targets for intervention against infection and subsequent disease. UL12 is the viral 5'-3' exonuclease, which is required for the production of infectious progeny. In this study, we show that in the absence of UL12, viral replication fork progression is abrogated. These data point to UL12 as an attractive target for intervention, which could lead to better clinical outcomes of HSV-1-associated disease in the future.

Discovering Lassa virus nucleoprotein inhibitors via in silico drug repositioning approach

Lassa fever, caused by the zoonotic Lassa virus (LASV), poses a significant health threat in Africa, leading to thousands of infections and deaths annually and has the potential to spread to other parts of the world. Despite the urgency for effective treatments, there are currently no approved drugs or vaccines for Lassa fever. LASV possesses a unique negative-sense RNA genome, and NP plays a crucial role in viral assembly and infection. Crystallographic analysis reveals distinct domains in NP, with the N-terminal domain involved in RNA binding and the C-terminal domain exhibiting exoribonuclease activity, suppressing type I interferon-mediated immune responses. This study explores the potential of repurposing existing FDA-approved drugs by targeting the N-terminal domain of LASV’s nucleoprotein (NP). Docking simulations and molecular dynamics experiments were conducted, revealing promising interactions between NP and widely used and well tolerated drugs such as metacycline, eltrombopag, glimepiride, lurasidone, paliperidone, prednisone, doxazosin, flavin mononucleotide, and pimozide. These drugs exhibited stable binding throughout 100 ns simulations, with interactions resembling those observed with the natural ligand, dTTP. Binding free energy calculations identified key amino acids, particularly Phe176 and Arg300, as crucial for drug-NP interactions. Notably, drugs like FMN, prednisone, metacycline, pimozide, and glimepiride displayed binding affinities comparable to dTTP, suggesting their potential as LASV inhibitors. The study underscores the importance of further experimental and clinical validation of these in silico findings. The identified drugs present promising candidates for potential treatments for Lassa fever, addressing the current gap in approved therapeutics for this life-threatening infectious disease.

Leaky Vaccines: A Wicked Problem in Accelerated Vaccine Development

While no vaccine can provide 100 percent protection, a high standard of regulatory safety, efficacy and quality is essential for public trust and the uptake of vaccines as essential global public health tools. This article addresses a growing concern that suboptimal “leaky” vaccines threaten emergency response to pandemics as well as routine public health programs. Agile regulatory standards now advance earlier approval of vaccines and therapeutics that may have suboptimal effectiveness. The benefit-harm trade- offs that play an enormous role in regulatory assessment and all stages of vaccine development and delivery deserve better public scrutiny, transparency, and accountability. Drawing on the case of the first licensed malaria vaccine, RTS,S Mosquirix™, in light of the rapid approval of COVID-19 vaccines, we consider the socio-technical implications of leaky vaccines in global vaccine logics and suggest possibilities for building legitimacy to inform the next generation of regulatory technology policy.

Better, Faster, Stronger: Accelerating mRNA-Based Immunotherapies With Nanocarriers.

Messenger ribonucleic acid (mRNA) therapeutics are attracting attention as promising tools in cancer immunotherapy due to their ability to leverage the invivo expression of all known protein sequences. Even small amounts of mRNA can have a powerful effect on cancer vaccines by promoting the synthesis of tumor-specific antigens (TSA) or tumor-associated antigens (TAA) by antigen-presenting cells (APC). These antigens are then presented to T cells, eliciting strong antitumor immune stimulation. The potential of mRNA can be further enhanced by expressing immunomodulatory agents, such as cytokines, antibodies, and chimeric antigen receptors (CAR), enhancing tumor immunity. Recent research also explores mRNA-encoded tumor death inducers or tumor microenvironment (TME) modulators. Despite its promise, the clinical translation of mRNA-based anticancer strategies faces challenges, including inefficient targeted delivery invivo, failure of endosomal escape, and inadequate intracellular mRNA release, resulting in poor transfection efficiencies. Inspired by the approval of lipid nanoparticle-loaded mRNA vaccines against coronavirus disease 2019 (COVID-19) and the encouraging outcomes of mRNA-based cancer therapies in trials, innovative nonviral nanotechnology delivery systems have been engineered. These aim to advance mRNA-based cancer immunotherapies from research to clinical application. This review summarizes recent preclinical and clinical progress in lipid and polymeric nanomedicines for delivering mRNA-encoded antitumor therapeutics, including cytokines and antibody-based immunotherapies, cancer vaccines, and CAR therapies. It also addresses advanced delivery systems for direct oncolysis or TME reprogramming and highlights key challenges in translating these therapies to clinical use, exploring future perspectives, including the role of artificial intelligence and machine learning in their development.

Borrowing Regulatory Capacity in Middle-Income Countries during Public Health Crises: Brazil, Regulatory Reliance, and the Politics of COVD-19 Vaccine Regulation

The COVID-19 pandemic underscored the critical role of states’ regulatory capacities. Countries had to authorize novel vaccine technologies in the context of scientific uncertainty and political pressure, issues particularly acute in middle-income countries (MICs) less familiar with the procedures needed to streamline regulatory processes during a crisis. How did regulatory agencies in countries still building their regulatory capacities expedite the authorization of new COVID-19 vaccines to combat the pandemic? How did they navigate political pressures to expedite vaccine approval while maintaining safety and efficacy standards? We explore these questions through the case of Brazil, which has one of Latin America’s most highly-regarded regulatory authorities, but was subject to acute political conflicts. In response to these tensions, the Brazilian National Health Surveillance Agency (Anvisa) leveraged “regulatory reliance” to expedite the authorization of COVID-19 vaccines. Regulatory reliance, the practice of relying on the decisions and procedures of external advanced regulatory agencies, allowed Anvisa to bolster its internal capacity and navigate domestic political challenges. This paper highlights the dual benefits of regulatory reliance: enhancing regulatory efficiency during crises and mitigating politicization pressures. The findings demonstrate that MICs can better respond to public health emergencies by integrating external expertise, thus contributing to global regulatory resilience. In addition, the implications extend to broader regulatory political economy discussions, suggesting that reliance mechanisms can fortify less mature regulatory systems and promote convergence even in the absence of global harmonization.

An Overview on Disease Burden and Management of Respiratory Syncytial Virus Infections in Older Adults in the Asia-Pacific Region.

Respiratory syncytial virus (RSV) represents a significant burden on older adults (aged ≥ 50years) globally and can lead to acute respiratory tract infections with substantial morbidity and mortality. However, there is a significant gap in knowledge regarding RSV infection in older adults, particularly in the Asia-Pacific region. This knowledge gap underscores the need for targeted and comprehensive studies to fully understand the nuanced epidemiology of RSV in ageing populations. This review synthesises data from various countries, emphasising the impact of RSV on older populations in the Asia-Pacific region. The overall proportions of RSV-related ARIs among older patients ranged from 0.2% to 5.6%. Among older adult patients with CAP, RSV accounted for 1.1%-10.3% of cases. However, it is crucial to note that the diversity in reported percentages highlights the influence of factors such as geographic location, health care settings and diagnostic practices. The most common symptoms observed in older adults with RSV infection were cough, sputum production and fever, followed by dyspnoea, sore throat and rhinorrhoea. Most of the old adults with RSV infection had underlying diseases, and RSV can cause significant morbidity and mortality in old adults. Treatment of RSV infections predominantly involve supportive care, with aerosolised ribavirin reserved for severe cases, especially immunocompromised patients. Emerging antiviral agents, including fusion and nucleoprotein inhibitors, offer promising avenues for future therapeutics. The recent approval of the bivalent RSV prefusion F protein-based vaccine for individuals aged 60 and older represents a milestone in preventive strategies. In conclusion, RSV infection remains a significant threat to older adults in the Asia-Pacific region, necessitating ongoing research and surveillance efforts. The recent vaccine approval marks a positive milestone, but further studies are crucial for refining prevention and treatment approaches.

Proteomic approach to identify host cell attachment proteins provides protective Pseudomonas aeruginosa vaccine antigen FtsZ

Pseudomonas aeruginosa is an opportunistic Gram-negative pathogen that causes severe nosocomial infections in susceptible individuals due to the emergence of multidrug-resistant strains. There are no approved vaccines against P. aeruginosa infections nor candidates in active clinical development, highlighting the need for novel candidates and strategies. Using a cell-blot proteomic approach, we reproducibly identified 49 proteins involved in interactions with human lung epithelial cells across four P. aeruginosa strains. Among these were cell division protein FtsZ and outer membrane protein OpmH. Escherichia coli BL21 cells overexpressing recombinant FtsZ or rOpmH showed a 66- and 15-fold increased ability to attach to 16HBE14o− cells, further supporting their involvement in host cell attachment. Both antigens led to proliferation of NK and CD8+ cytotoxic T cells, significant increases in the production of IFN-γ, IL-17A, TNF and IL-4 in immunised mice and elicited strong antigen-specific serological IgG1 and IgG2c responses. Immunisation with FtsZ significantly reduced bacterial burden in the lungs by 1.9-log CFU and dissemination to spleen by 1.8-log CFU. The protective antigen candidate, FtsZ, would not have been identified by traditional approaches relying on either virulence mechanisms or sequence-based predictions, opening new avenues in the development of an anti-P. aeruginosa vaccine.

Pangenome analysis of five representative Tropheryma whipplei strains following multiepitope-based vaccine design via immunoinformatic approaches.

Whipple disease caused by Tropheryma whipplei a gram-positive bacterium is a systemic disorder that impacts not only the gastrointestinal tract but also the vascular system, joints, central nervous system, and cardiovascular system. Due to the lack of an approved vaccine, this study aimed to utilize immunoinformatic approaches to design multiepitope -based vaccine by utilizing the proteomes of five representative T. whipplei strains. The genomes initially comprised a total of 4,844 proteins ranging from 956 to 1012 proteins per strain. We collected 829 nonredundant lists of core proteins, that were shared among all the strains. Following subtractive proteomics, one extracellular protein, WP_033800108.1, a WhiB family transcriptional regulator, was selected for the chimeric-based multiepitope vaccine. Five immunodominant epitopes were retrieved from the WhiB family transcriptional regulator protein, indicating MHC-I and MHC-II with a global population coverage of 70.61%. The strong binding affinity, high solubility, nontoxicity, nonallergenic properties and high antigenicity scores make the selected epitopes more appropriate. Integration of the epitopes into a chimeric vaccine was carried out by applying appropriate adjuvant molecules and linkers, leading to the vaccine construct having enhanced immunogenicity and successfully eliciting both innate and adaptive immune responses. Moreover, the abilityof the vaccine to bind TLR4, a core innate immune receptor, was confirmed. Molecular dynamics simulations have also revealed the promising potential stability of the designed vaccine at 400 ns. In summary, we have designed a potential vaccine construct that has the ability not only to induce targeted immunogenicity for one strain but also for global T. whipplei strains. This study proposes a potential universal vaccine, reducing Whipple's disease risk and laying the groundwork for future research on multi-strain pathogens.