Vaccine Development Research Articles

Extracellular vesicles-based vaccines: Emerging immunotherapies against cancer.

Cancer vaccines are promising therapeutic approaches to enhance specific T-cell immunity against most solid tumors. By stimulating anti-tumor immunity, clearing minimal residual disease, and minimizing adverse effects, these vaccines target tumor cells and are effective when combined with immune checkpoint blockade or other immunotherapies. However, the development of tumor cell-based vaccines faces quality issues due to poor immunogenicity, tumor heterogeneity, a suppressive tumor immune microenvironment, and ineffective delivery methods. In contrast, extracellular vesicles (EVs), naturally released by cells, are considered the ideal drug carriers and vaccine platforms. EVs offer highly organ-specific targeting, induce broader and more effective immune responses, and demonstrate superior tissue delivery ability. The development of EV vaccines is crucial for advancing cancer immunotherapy. Compared to cell-based vaccines, EV vaccines produced under Good Manufacturing Practices (GMP) offer advantages such as high safety, ease of preservation and transport, and a wide range of sources. This review summarizes the latest research findings on EV vaccine and potential applications in this field. It also highlights novel neoantigens for the development of EV vaccines against cancer.

An efficient in vivo feeding method for poultry red mites, Dermanyssus gallinae (Acari: Dermanyssidae).

Dermanyssus gallinae (D. gallinae), the poultry red mite (PRM), is a haematophagous pest infesting poultry and wild birds. In studies of the biology of D. gallinae and the development of vaccines and systemic acaricides against the mites, it is often necessary to feed the mites under laboratory conditions. Although several feeding methods have been developed, however, some defects exist in these methods, such as low engorgement rate, low oviposition of mites, and difficulty in mite recovery after feeding. In this study, we developed an in vivo feeding method for D. gallinae based on a feeding device consisting of a fixing device and a feeding-storage device, which made the introduction and recovery of mites convenient, and provided protection of the mites during feeding. Under optimized conditions, the mean engorgement rate for adult female mites, protonymphs, and deutonymphs were 86.80 ± 6.57 %, 50.80 ± 12.85 %, and 62.8 ± 7.82 %, respectively. The average oviposition rate was 98.5 ± 1.38 %, with an average of 5.35 ± 0.41 eggs per mite, and an egg hatching rate of 98.92 ± 0.45 %. Additionally, the mean molting rate for protonymphs and deutonymphs fed with the device, were 97.68 % ± 3.18 % and 92.57 % ± 3.78 %, respectively. The whole life cycle of the mites could be completed with this method. The highly reliable feeding method established in this research exhibits potential application in the biological research of D. gallinae as well as in the development of novel control methods.

The multifaceted role of XCL1 in health and disease.

The chemokine XC motif chemokine ligand 1 (XCL1) is an unusually specialized member of a conserved family of around 50 small, secreted proteins that are best known for their ability to stimulate the directional migration of cells. All chemokines adopt a very similar folded structure that binds a specific G protein-coupled receptor (GPCR), and most chemokines bind extracellular matrix glycosaminoglycans, often in a dimeric or oligomeric form. Owing in part to the lack of a disulfide bond that is conserved in all other chemokines, XCL1 interconverts between two distinct structures with distinct functions. One XCL1 fold resembles the structure of all other chemokines (chemokine fold), while the other does not (alternate fold). The chemokine fold of XCL1 displays high affinity for the GPCR XCR1, while the alternative fold binds GAGs and exhibits antimicrobial activity. Although the canonical role of XCL1 as a CD8+ dendritic cell chemoattractant was defined more than a decade ago, the misconception that XCL1 is a lymphocyte-specific chemoattractant still prevails in the recent literature. This review aims to highlight the structure-guided functions of XCL1 and reclarify its immunological role. In addition, the implications of this metamorphic chemokine in vaccine development and emerging functions in the nervous system will be explored.

New insights into gold nanoparticles in virology: A review of their applications in the prevention, detection, and treatment of viral infections.

Viral infections have led to the deaths of millions worldwide and come with significant economic and social burdens. Emerging viral infections, as witnessed with coronavirus disease 2019 (COVID-19), can profoundly affect all aspects of human life, highlighting the imperative need to develop diagnostic, therapeutic, and effective control strategies in response. Numerous studies highlight the diverse applications of nanoparticles in diagnosing, controlling, preventing, and treating viral infections. Due to favorable and flexible physicochemical properties, small size, immunogenicity, biocompatibility, high surface-to-volume ratio, and the ability to combine with antiviral agents, gold nanoparticles (AuNPs) have shown great potential in the fight against viruses. The physical and chemical properties, the adjustability of characteristics based on the type of application, the ability to cross the blood-brain barrier, the ability to infiltrate cells such as phagocytic and dendritic cells, and compatibility for complexing with various compounds, among other features, transform AuNPs into a suitable tool for combating and addressing pathogenic viral agents through multiple applications. In recent years, AuNPs have been employed in various applications to fight viral infections. However, a comprehensive review article on the applications of AuNPs against viral infections has yet to be available. Given their versatility, AuNPs present an appealing option to address various gaps in combating viral infections. Hence, this review explores the attributes, antiviral properties, contributions to drug delivery, vaccine development, and diagnostic uses of AuNPs.

Deciphering the genotypic diversity and epidemiology of scrub typhus genotypes in India: A systematic review and meta-analysis.

Scrub typhus is a significant cause of Acute Febrile Illness in India and presents a range of clinical manifestations influenced by the genotypes of the causative agent, Orientia tsutsugamushi. Understanding the distribution of these genotypes is crucial for public health planning, diagnostic accuracy, and vaccine development. In this systematic review, we analyzed 18 studies from an initial pool of 2013 records identified through database searches following PRISMA guidelines. The relevance of the findings to the genotype prevalence of Scrub typhus in India was taken into consideration throughout the selection process. Various genotyping methods, predominantly Polymerase Chain Reaction (PCR), were used in these studies to identify genotypes such as Karp, Gilliam, Kato, and others. The review revealed diverse prevalence rates of Scrub typhus genotypes across different Indian states. The Karp genotype is the most prevalent in India, with a pooled prevalence of 47%, followed by the Kato genotype at 40% and the Gilliam genotype at 28%. The Karp genotype showed significant variability, with prevalence rates ranging from 100% in Andhra Pradesh (2018) to 6.16% in Uttar Pradesh (2016-2017). The Kato genotype's presence varied significantly, with high prevalence in certain states like Karnataka and absence in others like Andhra Pradesh. The Gilliam genotype also displayed a unique distribution pattern, dominating in Uttar Pradesh with a prevalence of 93.8% in some years. Other genotypes like Boryong, IHS-II, Neimeng, Kuroki, TA763, and Kawasaki also showed varied prevalence across states. There was significant heterogeneity in the prevalence rates of different genotypes among studies, as indicated by I2 statistics. The diversity in Scrub typhus genotypes across India underscores the disease's complex epidemiology, presenting diagnostic challenges and opportunities for targeted public health interventions. For efficient disease management and control plans in India, it is imperative to understand the changing genetic landscape of scrub typhus through ongoing study and surveillance.

Structural profile and diversity of immunoglobulin genes in the Arctic Fox.

Immunoglobulins are important components of humoral immunity and play a crucial role in protecting the body from external antigens. The Arctic fox is an important member of furbearer farming, but due to the lack of research on the immune system of the Arctic fox, animal welfare regarding Arctic fox farming has still not received enough attention. In this study, we used the Arctic fox as a research subject, described the gene locus structure of the Arctic fox immunoglobulin germline by genome comparison, and analysed the mechanism of expression diversity of the antibody pool of the Arctic fox by rapid amplification of cDNA 5' ends and high-throughput sequencing. The results showed that the Arctic fox IgH, Igκ and Igλ loci were located on chromosome 6, chromosome 5 and chromosome 14, respectively. The number of variable (V) genes identified were 18, 11 and 10, and the number of joining (J) were 3, 4 and 13 and six diversity (D) genes in the heavy chain, respectively. Among them, the D genes, J genes and constant region genes of the heavy chain were arranged in the middle of the two variable heavy gene clusters; Arctic fox had a strong preference for the use of V genes, D genes and J genes, which resulted in a low level of V(D)J recombination diversity; linkage diversity analyses showed that random deletion of the V and J genes and insertion of the N and P nucleotides of the immunoglobulins of the Arctic foxes had a large impact on the linkage diversity of the IgH, whereas the light chain The linkage diversity was mainly contributed by the random deletion of V and J genes, and the insertion of N and P nucleotides had a smaller effect; somatic hypermutation (SHM) analysis showed that the mutation types of SHM of the heavy and light chains of the Arctic fox had a strong bias towards G>A and A>G, and the bias exhibited by the three chains was basically the same. By analysing the structure and expression diversity analysis of the Arctic fox gene loci, this study could provide a theoretical basis for antibody design and vaccine development in the Arctic fox, and provide new insights to further improve the animal welfare level of Arctic fox farming.

Novel vaccine strategies to induce respiratory mucosal immunity: advances and implications.

Rapid advances in vaccine technology are becoming increasingly important in tackling global health crises caused by respiratory virus infections. While traditional vaccines, primarily administered by intramuscular injection, have proven effective, they often fail to provide the broad upper respiratory tract mucosal immunity, which is urgently needed for first-line control of respiratory viral infections. Furthermore, traditional intramuscular vaccines may not adequately address the immune escape of emerging virus variants. In contrast, respiratory mucosal vaccines developed using the body's mucosal immune response mechanism can simultaneously establish both systemic and mucosal immunity. This dual action effectively allows the respiratory mucosal immune system to function as the first line of defense, preventing infections at the entry points. This review highlights the efficacy of respiratory mucosal vaccines, including innovative delivery methods such as nasal and oral formulations, in enhancing local and systemic immune barriers. Notably, respiratory mucosal vaccines offer potential advantages in protecting against emerging virus variants and maintaining long-term and multidimensional immune memory in the upper respiratory tract. In addition, a combination of intramuscular and respiratory mucosal delivery of vaccines largely improves their coverage and effectiveness, providing valuable insights for future vaccine development and public inoculation strategies.

Meeting summary: Global vaccine and immunization research forum, 2023.

At the 2023 Global Vaccine and Immunization Research Forum (GVIRF), researchers from around the world gathered in the Republic of Korea to discuss advances and opportunities in vaccines and immunization. Many stakeholders are applying the lessons of Covid-19 to future emergencies, by advancing early-stage development of prototype vaccines to accelerate response to the next emerging infectious disease, and by building regional vaccine research, development, and manufacturing capacity to speed equitable access to vaccines in the next emergency. Recent vaccine licensures include: respiratory syncytial virus vaccines, both for the elderly and to protect infants through maternal immunization; a new dengue virus vaccine; and licensure of Covid-19 vaccines previously marketed under emergency use authorizations. Malaria vaccine implementation is expanding and a second malaria vaccine has been recommended by the World Health Organization. In a setback for human immunodeficiency virus vaccine development, the only remaining Phase 3 trial has been discontinued. In immunization, greater clarity is emerging on the challenges of achieving access and equity, along with strategies to address those challenges. A better understanding of behavioral and social determinants of vaccine uptake and a validated toolkit for measuring and modifying the drivers of vaccination is informing program design and service delivery, contributing to improved uptake. Implementation research, which has been essential for human papillomavirus and malaria vaccine delivery, will be critical for delivering the new respiratory syncytial virus vaccines and for many other vaccines currently in development. The growing diversity of vaccines and complexity of immunization programs are leading to greater interest in simplified regimens, combination vaccines, and other innovations to facilitate delivery. Collaboration emerged as the unifying theme of GVIRF 2023, underscoring that the combined efforts of many contributors have enabled progress thus far, and going forward will continue to be essential to ensure equitable access to vaccines for all.

Precise intracellular uptake and endosomal release of diverse functional mRNA payloads via glutathione-responsive nanogels.

We present a novel, highly customizable glutathione-responsive nanogel (NG) platform for efficient mRNA delivery with precise mRNA payload release control. Optimization of various cationic monomers, including newly synthesized cationic polyarginine, polyhistidine, and acrylated guanidine monomers, allowed fine-tuning of NG properties for mRNA binding. By incorporating a poly(ethylene) glycol-based disulphide crosslinker, we achieved glutathione-triggered mRNA release, enabling targeted intracellular delivery. Our NGs demonstrated superior encapsulation (up to 89.3%) and loading (10.7%) efficiencies, with controlled mRNA release kinetics at intracellular glutathione concentrations. NGs outperformed commercial transfection reagents across multiple cell lines, including traditionally difficult-to-transfect lines. We demonstrate the platform's versatility by successfully delivering GFP mRNA, Mango II RNA aptamers, and functionally relevant β2-AMPK mRNA. Furthermore, we used TIRF microscopy to measure exact RNA copy number within the NGs. Notably, mechanistic cellular uptake studies revealed that disulphide-containing NGs exhibit enhanced cellular uptake and endosomal escape, potentially due to interactions with cell surface thiols. This work represents a highly tuneable, efficient, and biocompatible platform for mRNA delivery with relevance for gene therapy and vaccine development.

Evaluation of DF-1 cell culture based vaccine development for infectious bursal disease virus in Ethiopia.

Infectious Bursal Disease is a highly contagious, immunosuppressive viral disease of young chicks caused by the Infectious Bursal Disease Virus (IBDV). The study was carried out at the National Veterinary Institute (NVI) of Ethiopia to evaluate the competence of the DF-1cell culture adapted vaccine strain of IBDV as a vaccine candidate. DF-1cells at passage 27 confluent monolayer was infected with 1ml of LC-75 vaccine strain virus by adsorption method and recorded as passage 1 (P1). This procedure has been repeated up to seven serial passages with the same methods of virus infection onto DF-1cells. Minor CPEs were observed in the second passage, but vivid cytopathic effects (CPE) were observed starting from passage 3 (P3). The infectivity titer of DF-1cell adapted virus was determined, and the results showed a linear increase in titer with each passage number. Transcriptase polymerase chain reaction (RT-PCR) targeting the VP2 gene revealed positive 400-base pair amplification. The vaccinated experimental chicks from passages 5 and 7 and the CFC based vaccine showed no clinical signs and/or death. Efficacy test revealed that DF-1 adapted vaccinal strain protected the chicks from the challenged virus strain at passage 5 and 7. The control group, on the other hand, had 100% morbidity and 91% mortality. As a result, the DF-1cell could be used as a model to study IBDV kinetic growth, and the DF-1cell adapted virus could be a candidate for IBD vaccine development. Thus, IBD vaccine production using DF-1cells is recommended.

Development and immunogenicity evaluation of attenuated Salmonella typhimurium delivering porcine Deltacoronavirus S1 gene.

Porcine deltacoronavirus (PDCoV) is a swine enteropathogenic coronavirus that causes severe diarrhea in piglets, the development of novel vaccines is of great value in the prevention and control of PDCoV. Here, we selected attenuated Salmonella typhimurium SL7207 to deliver pVAX1-S1, resulting in the oral vaccine strain, SL7207 (pVAX1-S1). In immunized mice, SL7207 (pVAX1-S1) induced PDCoV-specific humoral IgG, IgA, neutralizing antibodies, mucosal sIgA, up-regulation of CD8+ T cells, and increased levels of Th1 cytokines (IFN-γ and IL-2). In piglets, SL7207 (pVAX1-S1) induced high levels of PDCoV-specific humoral IgG and neutralizing antibodies but no detectable IgA, and only low levels of mucosal sIgA. SL7207 (pVAX1-S1) also promoted T cell differentiation into CD4+ and CD8+ T cells, and increased the expression level of IFN-γ and IL-4 in peripheral blood. Challenge experiments in piglets showed SL7207 (pVAX1-S1) alleviated diarrhea, decreased fecal virus load and intestinal lesions compared with control groups. In conclusion, this study systematically evaluated the immunogenicity and feasibility of attenuated Salmonella typhimurium delivering PDCoV S1 gene, which will provide helpful reference information for further exploration of novel PDCoV oral vaccine.

An in vitro nanocarrier-based B cell antigen loading system; tumor growth suppression via transfusion of the antigen-loaded B cells in vivo.

B cell-based vaccines are expected to provide an alternative to DC-based vaccines. However, the efficacy of antigen uptake by B cells in vitro is relatively low, and efficient antigen-loading methods must be established before B cell-based vaccines are viable in clinical settings. We recently developed an in vitro system that efficiently loads antigens into isolated splenic B cells via liposomes decorated with hydroxyl PEG (HO-PEG-Lips). Therefore, the purpose of this study was to expand this system in order to achieve another approach to in vivo tumor growth suppression. By using HO-PEG-Lips as a carrier for model antigen OVA along with an adjuvant, α-galactosylceramide (GC), the amount of antigen loading to the B cells in vitro was increased compared with that of both free OVA and free GC. Transfusion of B cells treated with HO-PEG-Lips that encapsulated OVA and GC suppressed the growth of OVA-expressing murine thymoma (E.G7-OVA) tumors in vivo through strong induction of OVA-specific T cells. Under fluorescence microscopic observation, migration of the transfused B cells in the spleens of recipient mice were confirmed. Our results indicate that our novel antigen-loading system could become a promising approach to facilitate the development of cell-based therapeutic cancer vaccines utilizing B cells as alternative APCs.

Evaluation of the safety and immune protection of OMPAC, PAPF, and EBPSs recombinant subunit vaccines Developed for Escherichia coli, Staphylococcus aureus, and Streptococcus agalactiae in mice.

Bacterial mastitis in dairy cow is often caused by a combination of bacterial infections, such as Escherichia coli, Staphylococcus aureus, and Streptococcus agalactiae. Currently, there is no effective vaccine against the disease. Therefore, we constructed a recombinant subunit vaccine by fusing gene fragments of E. coli OMPA and OMPC, S. aureus EBPS, and S. agalactiae PGK, AP1, AP2, and FBSA. These gene fragments were combined into three fusion proteins: OMPAC, EBPSs, and PAPF. Mice were immunized with the three fusion proteins either alone or in combination. The test results showed that immunization with OMPAC, EBPSs, and PAPF individually or in combination could induce high titers of antibodies in the mice. Additionally, 21days post-immunization, IFN-γ levels were significantly increased in all groups of mice, suggesting that immunization with OMPAC, EBPSs, and PAPF, whether alone or in combination, was effective in inducing antibody production. This indicates that OMPAC, EBPSs, and PAPF were effective in inducing both humoral and cellular immunity in mice. Furthermore, immunization with OMPAC, EBPSs, and PAPF individually or in combination were effective in protecting mice from E. coli, S. aureus, and S. agalactiae infections. Importantly, a mixture of the three fusion proteins was relatively safe for pregnant female mice. In conclusion, we successfully constructed and expressed recombinant subunit vaccines of OMPAC, EBPSs and PAPF and verified that these vaccines rapidly induced high levels of specific antibodies while reducing bacterial loads in the organs of mice. This lays the theoretical foundation and data support for the development of novel subunit vaccines against mastitis in dairy cows.

Examining homology between MPXV and immunogenic VACV-derived peptides.

The mpox virus (MPXV) came to global attention with the 2022 global outbreak. Current vaccination and post-exposure prophylaxis against MPXV consists of live vaccinia whole virus-based vaccines including ACAM2000®, JYNNEOS™, and LC16m8 originally developed against smallpox. Here, we analyzed 152 vaccinia-derived peptides we identified by mass spectrometry for homology with MPXV-1 and MPXV-2 sequences to evaluate their potential relevance to MPXV-specific immunity. We found that 93 (61.2%) of these sequences were 100% homologous to both clades. This supports the long-standing hypothesis that immunologic cross-reactivity is due to sequence homology between poxviruses. Our results also suggest the utility of VACV-derived peptides for an mpox peptide-based vaccine candidate. The development of peptide-based vaccines against MPXV could offer significant advantages over currently available vaccines, such as no cold chain requirement, stability, and reduced manufacturing costs.

Preclinical development of the lipid nanoparticle–based mRNA vaccine with multiple natural T cell epitopes for pancreatic cancer.

752 Background: Immunotherapy has recently emerged as a promising avenue in cancer treatment; however, its effectiveness on pancreatic ductal adenocarcinoma (PDAC) is hindered by the lack of effector T cells in the tumor microenvironment. One of the strategies to overcome the resistance of PDAC to immunotherapy involves identifying immunogenic tumor-associated and specific antigens for the development of personalized cancer vaccines. The mRNA platform has become an attractive platform for antigen presentation. The delivery of mRNA cancer vaccines via lipid nanoparticles (LNPs) enables intracellular delivery and controlled release of the payload, offering improved vaccine efficacy. However, mRNA vaccines presenting human T cell epitopes often lack a preclinical model for antitumor immune efficacy testing. Methods: A syngeneic mouse model of PDACs was established by implanting KPC tumor cells into the livers by hemispleen surgery. mRNA vaccine expressing five 25-mer peptide regions were synthesized. Two mouse CD8+ T cell epitopes were predicted. Their MHC binding was tested by the T2 binding assay. CD8+ T cells specific for these two epitopes were examined by ELISpot assays and were quantified by ImmunoSpot ELISpot Reader to identify changes in IFN-g secretion. Results: Using mass spectrometry analysis, we successfully identified natural HLA class I and class II-binding epitopes in the neoplastic tissues of human PDACs. For the design of mRNA vaccine, we chose five 25-mer peptide regions that each contains both class I and class II epitopes punctuated by AAY and GPGPG linkers and followed by an MITD sequence, which all aim to improve the efficiency of antigen presentation to dendritic cells. Using NetMHC, we predicted H2Kb or H2Db-binding epitopes LYPFPLAL and SMVQMTFL, within these five human peptide regions. The T2 binding assay showed a lack of evident binding of both peptides to the T2-Kb or T2-Db cells. However, the ELISpot assay showed that LYPFPLAL, but not SMVQMTFL, can induce the IFN-g expression from CD8+ T cells derived from splenocytes of the KPC tumor mice vaccinated by a peptide vaccine containing both peptides. Therefore, this result confirmed that LYPFPLAL is a mouse CD8+ T cell epitope and can be used to monitor antigen-specific CD8+ T cell response in response to the mRNA vaccine treatment in the syngeneic mouse model of PDACs. Conclusions: Antitumor efficacy of our above-designed mRNA vaccine can be tested in the syngeneic mouse hemispleen model of KPC tumors. Mouse LYPFPLAL epitope-specific CD8+ T cell response can serve as a surrogate marker for the antitumor efficacy of this mRNA vaccine in mouse models for PDAC.

Mucosal immunity elicited by a human-Fcγ receptor-I targeted intranasal vaccine platform enhances resistance against nasopharyngeal colonization of Streptococcus pneumoniae and induces broadly protective immunity against respiratory pathogens.

The development of safe and effective mucosal vaccines are hampered by safety concerns associated with adjuvants or live attenuated microbes. We previously demonstrated that targeting antigens to the human-Fc-gamma-receptor-I (hFcγRI) eliminates the need for adjuvants, thereby mitigating safety concerns associated with the mucosal delivery of adjuvant formulated vaccines. Here we evaluated the role of the route of immunization in the mucosal immunity elicited by the hFcγRI-targeted vaccine approach. To enable Ag targeting, PspA from Streptococcus pneumoniae (Sp) was genetically fused with the hFcγRI-targeting antibody (α-hFcγRI) to generate PspA-FP. Intranasal (IN) immunization with the PspA-FP induced significantly higher IgA, IgG, and memory T cell response in the lung mucosa compared to that of the intramuscular (IM) route, while both routes exhibited similar increase in the systemic IgG response. The IN immunization elicited better resistance against nasal colonization (NC) of Sp compared to the IM immunization. Additionally, the resistance to NC with the IN administered PspA-FP was higher than the PspA-Alum formulation administered by the IM route. While the protection form lethal pulmonary Sp infection correlated with the systemic Ab response, the resistance from NC (of Sp) correlated with the mucosal immune response. Similar to the pneumococcal pneumoniae model, the hFcγRI-targeted vaccine (based on HA as Ag) was equally protective against pulmonary Influenza virus infection via both routes. However, the IN route promoted better protection compared to the IM route against a lethal pulmonary infection with Francisella tularensis (Ft). The enhanced protection against Ft correlated with the superior mucosal immune response elicited by the IN route compared to the IM route. These observations showed a differential requirement for mucosal delivery for protection depending on the type of pathogen. Moreover, this study revealed that the hFcγRI-targeted vaccine platform is broadly-effective as an adjuvant-free mucosal vaccine platform against respiratory pathogens.

Genetic characterization of infectious bursal disease virus strains with distinct VP2 amino acid profiles emerging in Pakistan.

Infectious bursal disease (IBDV) poses a significant threat to the global poultry industry and causes major economic losses. This study presents the genetic profile of IBDV strains emerging in Pakistan, focusing on the VP2 amino acid profile. The effects of these changes on disease transmission, vaccine effectiveness, and overall chicken health are concerning. A meticulous analysis was carried out by isolating and clustering IBDV strains collected from Faisalabad district of Pakistan. The genetics of these viruses were evaluated by analyzing the VP2 gene, the main component of the virus. Importantly, our results reveal the existence of IBDV strains with unprecedented VP2 amino acid profiles, indicating genetic changes that may affect virulence and immunity. This study highlighted the changing IBDV landscape in Pakistan and underscores the importance of continued research and surveillance efforts. Understanding the genetic structure of these emerging diseases is essential for developing effective control strategies, including vaccine development and control. This also emphasized the need for international cooperation to reduce the spread of the new IBDV strains, which could significantly impact the poultry industry outside Pakistan.

Functional characterization of MMAR_1296 in Mycobacterium marinum and its potential as a vaccine candidate.

The Pro-Glu/Pro-Pro-Glu (PE/PPE) family proteins in mycobacteria plays a crucial role in pathogenesis and immune evasion. These proteins characterized by unique structures with conserved sequences. This study elucidated the specific immunological functions of MMAR_1296 from marine mycobacterium. Expressing MMAR_1296 in Mycobacterium smegmatis (M. smegmatis) led to significant alterations in bacterial morphology, as well as reduced survival of M. smegmatis under adverse in vitro conditions and within macrophages. Furthermore, transcriptome analysis of mouse macrophages indicated that natural immunity-related pathways were upregulated in the group infected with M. smegmatis recombinantly expressing MMAR_1296. Moreover, the mycobacterium Growth Inhibition Assays(MGIA)in mice demonstrated that M. smegmatis expressing MMAR_1296 exerted a significant inhibitory effect against Mycobacterium abscessus (M. abscessus) and Mycobacterium marinum (M. marinum) infections. Immunization challenge experiments in mice further confirmed its protective effects, showing a reduction in organ bacterial loads by 1 log10 value compared to the positive control group. These findings indicate that MMAR_1296 is a promising vaccine candidate for M. abscessus and M. marinum. Given that PE/PPE protein family is also a crucial component of Mycobacterium tuberculosis (M. tuberculosis) antigens, further exploration of sequence functions based on MMAR_1296 could reveal broader applications of PE/PPE proteins family for M. tuberculosis treatment. This study supported vaccine development targeting PE/PPE proteins in mycobacteria and paves the way for broader applications.

Development of an oral vaccine delivery system for shrimp aquaculture using attenuated Listeria monocytogenes

Shrimp aquaculture faces major challenges from viral diseases, such as the white spot syndrome virus (WSSV), leading to high mortality and economic losses. Vaccination offers a potential solution, but practical oral delivery systems remain limited. Therefore, this study aims to elucidate the feasibility of using heat-killed attenuated Listeria monocytogenes (HKALM) as a safer alternative for plasmid delivery in shrimp. A triple-layered safety approach—bacterial attenuation, a suicide mechanism, and heat-killing—was implemented to minimize environmental risks. HKALM effectively delivered plasmids into shrimp hemocytes and intestinal cells, with the green fluorescent protein used as a reporter to enable detectable gene expression. Additionally, expressing the WSSV envelope protein VP53A through HKALM significantly increased phenoloxidase activity and improved shrimp survival rates after WSSV infection. These findings suggest that HKALM offers a safer, scalable platform for oral vaccine development in shrimp aquaculture, addressing critical challenges in disease management.

Comparative RNA sequencing analysis of three Capripoxvirus infections in an immortalized hTERT-bOEC cell model.

Capripoxviruses (CaPVs), such as lumpy skin disease, sheep pox, and goat pox, cause significant production and economic losses and are major constraints to the growth of livestock production in endemic areas. Understanding the pathogenic mechanism of CaPVs and their translation into clinical applications depends on the availability of a suitable cell line. In this study, we used a lentiviral packaging system to establish an immortalized hTERT-bOEC cell line by ectopic introduction of human telomerase reverse transcriptase (hTERT). Western blotting, indirect immunofluorescence, and flow cytometry analyses revealed that hTERT was successfully integrated into the genome of hTERT-bOEC cells. Crucially, this hTERT-bOEC cell line was highly susceptible to LSDV, SPPV, and GTPV infections. Establishing hTERT-bOECs is critical for basic research, clinical application, and vaccine development related to CaPVs. Furthermore, RNA-seq analyses revealed a similar differential expression of genes and enrichment of signaling pathways to CaPV infections in hTERT-bOECs. Real-time quantitative qPCR further confirmed the top five up-regulated and down-regulated differentially expressed genes among the CaPV infections. Transcriptome analyses provide deep insight into the biological characteristics of the replication process in CaPV infections.