Search Results (2,453)

Background/Objectives: Streptococcus suis is a zoonotic pathogen that causes infections in pigs and humans, leading to significant economic losses. S. suis can evade the immune system of hosts and induce persistent infections. Early detection and vaccination are crucial for controlling the disease in swine industries. This study aimed to investigate candidate recombinant protein for antibodies against S. suis detection and subunit vaccine development. Methods: The whole genome of S. suis BM407 was analyzed using bioinformatic tools to predict suitable proteins and genes for recombinant protein expression. Partial extracellular factor protein (epf) genes of S. suis serotype 2 DMST18783 were amplified. A 3301 bp amplicon was digested, and a specific 615 bp fragment was inserted into a pQE81L-KAN vector. Then, the constructed plasmid was cloned and expressed in Escherichia coli DH10β. Purified protein was analyzed using SDS-PAGE. In addition, translated amino acid sequences were analyzed for immune response properties, molecular docking, molecular dynamic simulation, and epitope prediction. Results: The amino acid sequence of recombinant extracellular factor protein (rEF) was revealed as a promising antigen containing putative protective regions as linear epitopes. Furthermore, the rEF was expressed as a histidine-tagged recombinant protein, and its properties were nearly similar to the predicted rEF using bioinformatic tools. Binding of the recombinant EF (rEF) protein was found to reduce fluctuations in the swine toll-like receptor 2. Furthermore, the rEF contained several regions that were predicted to be epitopes for both B-cells and T-cells. Conclusions: This study indicates that the recombinant EF fragment is a promising candidate for detecting antibodies against S. suis and as a component of a subunit vaccine. Full article

Porcine epidemic diarrhea (PED), a severe and highly contagious disease induced by porcine epidemic diarrhea virus (PEDV), impacts pigs across all age groups but has a particularly high lethality in neonatal piglets, with mortality rates reaching 80 to 100%, leading to substantial economic losses in the swine industry. In this investigation, 128 intestinal samples obtained from 65 large-scale pig farms in eight prefectures of Guangdong Province were screened by RT-qPCR between 2022 and 2024. Of these, 50 samples (39.06%) tested positive for Porcine Epidemic Diarrhea Virus (PEDV). The complete S1 genes of 31 representative strains were sequenced. Phylogenetic analysis revealed G2c as the exclusive dominant lineage (29/31, 93.6%), with single representatives of G2a and G2d. Nucleotide identity among the local strains ranged from 88.9 to 100% and 88.1 to 93.5% to prototype CV777 and from 91.2 to 99.1% to vaccine strain AJ1102. The COE neutralizing epitope (aa 499–638) carried 26 substitutions versus AJ1102; T499I/S, A520S/L, F539L, K566N and F615L were most prevalent. The SS2 epitope was fully conserved, whereas SS6 showed three low-frequency changes (S766P, S769F, G770V). Six distinct N-glycosylation patterns were identified relative to AJ1102. The predominance of G2c, accompanied by marked epitope drift and altered glycosylation, indicates the need for further investigation into vaccine efficacy. Continuous surveillance and the careful evaluation of G2c-based vaccine candidates are warranted. Full article

This study aimed to characterize Mycoplasmosis bovis strain 16M—a highly virulent isolate from one Chinese outbreak—as a candidate for challenge models and inactivated vaccine development. We assessed strain 16M through morphological observation, PCR identification, drug susceptibility testing, growth titer and biofilm quantification, immunological profiling, and calf challenge experiments. We used genomic resequencing to evaluate the genetic stability across 150 passages. Classified as the prevalent ST52 lineage in China, strain 16M showed phylogenetic proximity to strain 08M and exhibited multidrug resistance (notably to macrolides). It achieved higher titers and stronger biofilm formation than other isolates and the reference strain PG45. In calves, intratracheal inoculation with 16M induced universal infection, severe pulmonary consolidation, and peribronchial cuffing, with significantly higher disease scores (p < 0.01). The inactivated 16M vaccine elicited elevated antigen-specific IgG titers, PBMC proliferation, and IFN-γ production versus PG45. Post challenge, immunized calves showed reduced pathological lesions, shorter bacterial shedding, and lower disease scores than the infected controls (p < 0.05). Genetic stability was confirmed for virulence-associated genes (e.g., adhesion proteins), with stable titers and biofilm production within 50 generations. Strain 16M combines high virulence for challenge modeling and industrial-scale vaccine suitability, owing to its robust growth, stable immunogenicity, and genetic consistency. Full article

Background: Varicella zoster virus (VZV) is a globally circulating pathogen that usually infects children and establishes a latent state in host nerve cells. Recurrence of latent varicella zoster virus (VZV) is often triggered by predisposing factors such as aging and immune dysfunction, which may lead to herpes zoster (HZ) and its related complications. At present, there is no specific treatment for herpes zoster or postherpetic neuralgia, so vaccination is an important preventive measure. Methods: In this study, a variety of vaccine formulations were developed by combining the gE protein with different adjuvants. Enzyme-linked immunosorbent assay (ELISA), flow cytometry, and ELISpot were used to evaluate the immune response induced by each combination of vaccines in C57BL/6 mice, and the optimal combination of adjuvants. Then, its immunogenicity was verified in SD rats and rhesus monkeys. Results: All combinations of gE/squalene oil-in-water emulsion (SWE)/CpG1018 adjuvant induced a good humoral immune response 28 days after secondary immunization. GE/SWE/CPG1018, combined with adjuvant, induced a higher cellular immune response in mice. The selected gE/SWE/CpG1018 combined with the adjuvant vaccine combination could effectively stimulate the humoral and cellular immune responses in SD rats and rhesus monkeys. Conclusions: The gE/SWE/CpG1018 combined with adjuvant vaccine may be a low-cost and highly effective vaccine candidate for the prevention of varicella zoster. Full article

Background/Objectives: Rabies is a fatal zoonotic disease caused by the rabies virus (RABV), and effective therapeutic treatments are currently lacking. Vaccination remains the primary strategy for rabies control. The Semliki Forest virus-rabies virus glycoprotein (SFV-RVG), a virus-like vesicle rabies vaccine combining Semliki Forest virus replicase and rabies glycoprotein, has shown potential as a promising vaccine candidate. This study aimed to optimize the production of SFV-RVG and evaluate adjuvant formulations to improve its immunogenicity in both mice and dogs. Methods: SFV-RVG production was optimized by determining the optimal multiplicity of infection (MOI) at 0.03 and cell density at 1 × 10⁶–1.3 × 10⁶ cells/mL, followed by scaling up the process in bioreactors. Eleven adjuvant formulations were tested in mice and dogs to assess their effects on immunogenicity. Cytokine analysis and antibody responses were measured, including IFN-γ, IL-4, IgG2a/IgG1 ratios, and neutralizing antibody titers. Results: The optimized SFV-RVG production was successfully scaled up, and M103 adjuvant induced rapid early antibody titers in mice. In dogs, GEL02 led to the highest neutralizing antibody levels, exceeding 40 IU/mL by 28 days post-immunization. Cytokine analysis indicated that both M103 and GEL02 significantly enhanced IFN-γ and IL-4 expression, balancing the Th1/Th2 immune response. SFV-RVG with GEL02 demonstrated stronger immunogenicity than a commercial vaccine, and challenge studies confirmed robust protection against lethal RABV in mice. Conclusions: This study establishes GEL02 as a superior adjuvant for rabies vaccines and provides a scalable SFV-RVG production process. These findings highlight SFV-RVG with GEL02 as a promising rabies vaccine candidate for dogs, offering significant potential for rabies control. Full article

Background/Objectives: Varicellovirus bovinealpha1 and Varicellovirus bovinealpha5 (BoAHV-1 and BoAHV-5), respectively, are widely distributed pathogens that cause distinct clinical conditions in cattle including infectious bovine rhinotracheitis, infectious pustular vulvovaginitis/balanoposthitis, and meningoencephalitis. Due to the establishment of viral latency, controlling these infections is challenging, and vaccination remains the most effective strategy. In this study, vaccine candidates targeting both BoAHV-1 and BoAHV-5 were developed. Methods: A synthetic gene encoding immunodominant epitopes from the gB and gD proteins and tegument phosphoprotein of BoAHV-1 and BoAHV-5 was designed to produce a multi-epitope recombinant antigen, expressed both in a prokaryotic system (RecBoAHV) and by a modified vaccinia Ankara (MVA-BoAHV) viral vector. The binding affinity of MHC-I to bovine leukocyte antigens (BoLA) was predicted using the NetMHCpan tool (version 4.1). The immunogenicity of the vaccine candidates was evaluated in rabbit and mouse models, using prime-boost immunization protocols. Sera from bovines naturally infected with BoAHV-1 and/or BoAHV-5 were used to evaluate the chimeric protein antigenicity. Immune responses were assessed by indirect ELISA and Western blot. Results: The recombinant multi-epitope protein was effectively recognized by IgG and IgM antibodies in sera from cattle naturally infected with BoAHV-1 or BoAHV-5, confirming the antigenic specificity. Both RecBoAHV and MVA-RecBoAHV induced strong and specific humoral immune responses in rabbits following a homologous prime-boost regimen. In mice, both homologous and heterologous prime-boost protocols revealed robust immunogenicity, particularly after the second booster dose. Conclusions: These findings highlight the immunogenic potential of the RecBoAHV multi-epitope vaccine candidates for controlling BoAHV-1 and BoAHV-5 infections. Further characterization of these vaccine formulations is currently underway in bovine, the target specie. Full article

Background/Objectives: African Swine Fever (ASF), caused by the African Swine Fever Virus (ASFV), is a highly contagious and lethal disease in pigs, for which no recognized safe and effective vaccine is currently available. The ASFV EP153R gene, expressed during both early and late infection stages, exhibits strong protective potential. Utilizing advances in genetic engineering, recombinant PRRSV vector vaccines carrying ASFV exogenous genes were constructed. This study aims to prepare pEP153R-based polyclonal antibodies and an iELISA detection method using the constructed rPRRSV-EP153R as a specific target to verify the iELISA’s specificity and effectiveness. Methods: A prokaryotic plasmid, pCold-TF-EP153R, was constructed to express protein in BL21 (DE3). The purified soluble protein (2 mg/mL) was used to generate a murine polyclonal antibody and establish an indirect ELISA. The EP153R gene was inserted between ORF1b and ORF2a of PRRSV via reverse genetics, yielding recombinant rPRRSV-EP153R. Its biological properties were assessed in vitro and in vivo. Results: The pEP153R was specifically detected by both anti-His antibody and generated polyclonal antibodies. An established iELISA showed high specificity, sensitivity, and 98.18% accuracy. The antibodies specifically recognized pEP153R expressed in recombinant virus and eukaryotic systems. Additionally, the recombinant virus stably maintained EP153R without changes in virological characteristics relative to vHuN4-F112. In vaccinated piglets, the rPRRSV-EP153R induced a specific, consistent, and detectable immune response. Conclusions: The established iELISA, characterized by high specificity, sensitivity, and accuracy, furnishes reliable technical support for the serological diagnosis of ASFV. Meanwhile, the recombinant virus rPRRSV-EP153R demonstrates potential as a novel live vectored vaccine candidate, with the capability to induce specific immunity against both ASFV and PRRSV. Full article

Invasive group A streptococcal (iGAS) infections are increasingly recognized as a global public health concern, with a notable resurgence observed among pediatric populations in high-income countries following the relaxation of COVID-19-related restrictions. While the most commonly implicated emm types in invasive disease are emm1 and emm3, the global distribution of Streptococcus pyogenes strains is highly diverse, posing challenges for surveillance and vaccine development. We describe a 3-year-old boy with a femoral subperiosteal abscess, a rare clinical manifestation of iGAS, caused by an emm6.10 S. pyogenes strain. The diagnosis was confirmed by positive blood cultures and magnetic resonance imaging. Antibiotic therapy included intravenous ceftriaxone followed by oral amoxicillin, and then prolonged oral clindamycin was introduced due to the deep-seated nature of the infection. Molecular typing was performed by the national reference center as part of routine surveillance of invasive strains. This case emphasizes the importance of recognizing atypical clinical presentations of iGAS in children and the crucial role of strain typing in epidemiological monitoring. It also illustrates how the remarkable emm-type diversity of S. pyogenes remains a major obstacle to effective vaccine design, despite ongoing efforts with multivalent M-protein-based candidates and alternative strategies targeting conserved antigens. Enhanced global surveillance and inclusive vaccine design are urgently needed to address the full spectrum of circulating GAS strains. Full article

Background/Objectives: Allergen-specific immunotherapy remains the only disease-modifying treatment for allergic diseases, and the use of recombinant hypoallergenic derivatives is a promising therapeutic approach. Among these, BTH2 has previously shown efficacy in an acute murine model of allergy induced by Blomia tropicalis. The present study aimed to evaluate both the efficacy and safety of BTH2 in a chronic asthma model induced by B. tropicalis. Methods: A/J male mice (n = 6) were sensitized and chronically challenged with B. tropicalis extract over four months. One group repeatedly received subcutaneous doses of BTH2 (25 µg) for three months (65 doses). Parameters of allergic airway inflammation, antibody profiles, cytokine levels, and markers of AIT success were evaluated in bronchoalveolar lavage fluid, lung tissue, serum, and splenocyte cultures. Results: Repeated BTH2 administration was well tolerated, with no signs of systemic toxicity. BTH2 significantly reduced neutrophilic and eosinophilic airway inflammation, while increasing lymphocytes and regulatory cytokines in the lungs. It suppressed IgE against B. tropicalis allergens, while inducing mucosal IgA responses and systemic IgG, which may be linked to the observed blocking antibody activity in BTH2-treated mice. The treatment also led to downregulation of Th2 cytokines and enhanced expression of regulatory and Th1-associated cytokines, especially IL-10, TGF-β and IFN-γ. Correlation matrix analyses indicated that regulatory cytokines were correlated with beneficial antibody responses and reduced inflammation. Conclusions: BTH2 shows strong therapeutic and immunomodulatory effects in a chronic asthma model induced by B. tropicalis, with a favorable safety profile. These findings support its potential for future clinical trials, including those involving patients with allergic asthma. Full article

Background: Mammalian orthoreovirus is a ubiquitous double-stranded RNA virus that causes mild respiratory and enteric infections, primarily in infants and young children. Its significant environmental stability and association with conditions like celiac disease highlight an unmet medical need, as no licensed vaccine or antiviral treatment currently exist. Methods: An immunoinformatics-driven approach was employed to design a multi-epitope vaccine. The highly antigenic inner capsid protein Sigma-2 was used to predict cytotoxic T lymphocyte (CTL), helper T lymphocyte (HTL), and linear B cell epitopes using NetCTL, NetMHCpan, NetMHCIIpan, and IEDB tools. Selected epitopes were fused with appropriate linkers. The construct’s antigenicity, allergenicity, and physicochemical properties were evaluated. The tertiary structure was predicted with AlphaFold2, refined, and validated. Molecular docking with TLR2 and TLR4 was performed using HDOCK, and immune response simulation was conducted with C-ImmSim. Finally, the sequence was codon-optimized for E. coli expression using JCat. Results: The final vaccine construct comprises one CTL, four HTLs, and one B cell epitope. It is antigenic (VaxiJen score: 0.5026), non-allergenic, and non-toxic and possesses favorable physicochemical properties, including stability (instability index: 32.28). Molecular docking revealed exceptionally strong binding to key immune receptors, particularly TLR2 (docking score: −324.37 kcal/mol). Immune simulations predicted robust antibody production (elevated IgM, IgG1, and IgG2) and lasting memory cell formation. Codon optimization yielded an ideal CAI value of 0.952 and a GC content of 57.15%, confirming high potential for recombinant expression. Conclusions: This study presents a novel multi-epitope vaccine candidate against reovirus, designed to elicit broad cellular and humoral immunity. Comprehensive in silico analyses confirm its structural stability, potent interaction with innate immune receptors, and high potential for expression. These findings provide a strong rationale for further wet-lab studies to validate its efficacy and advance it as a promising prophylactic candidate. Full article

Background/Objectives: Foot-and-mouth disease (FMD) remains a significant threat to livestock, particularly in the pool 1 region (East Asia), where serotype A is prevalent. Vaccination is the most effective control measure, and the selection of the appropriate vaccine strain is critical for ensuring effective protection. The A/ASIA/Sea-97 lineage (and its G1 and G2 sublineages) has been reported in this region, necessitating the development of an appropriate vaccine. This study aimed to develop a potent candidate vaccine strain capable of providing effective protection against the G1 and G2 sublineages of the A/ASIA/Sea-97 lineage. Methods: Chimeric vaccine development was achieved by replacing and inserting antigenic sites derived from the A/ASIA/Sea-97 G1 (VP4, VP2, and VP3) and G2 sublineage (VP1 and GH loop) strains. The candidate strains were evaluated for protective efficacy in mice and pigs. Results: In mice, the two candidate vaccines provided strong protection against challenge with a G1 sublineage virus (A/POC/2010) and A22 Iraq and two G2 sublineage viruses (A/YC/2017 and A/GP/2018). Subsequently, the most effective candidate was selected for testing in pigs. One month after vaccination, the pigs were protected against two A/ASIA/Sea-97 viruses (A/POC/2010 and A/GP/2018) prevalent in East Asia. Conclusions: These results demonstrate that the developed strain has significant potential as a vaccine against the type A FMD viruses circulating in East Asia and that vaccination with this strain could be an effective strategy for regional FMD control. Full article

African swine fever (ASF), caused by the African swine fever virus (ASFV), is an acute, febrile, highly contagious, and lethal disease that poses a severe threat to the global pig farming industry. Currently, no globally recognized, safe, and effective commercial ASF vaccine has been developed, making vaccination a crucial strategy for outbreak control. The ASFV structural proteins p72, p30, and p54 are key targets for vaccine development. In this study, we developed a novel baculovirus vector-based system for surface display of a recombinant protein comprising epitopes from p72, p30, and p54. Upon infection, the recombinant protein was expressed and anchored on the plasma membrane of Sf-9 cells. Purified virus analysis revealed that the Bac-recombinant protein enhanced gene delivery and transgene expression in mammalian cells compared to the Bac-Wild Type (Bac-WT). In a murine model, the Bac-recombinant protein induced significantly higher IFN-γ and IL-4 levels than Bac-p30 and the negative control. However, further evaluation in swine models is required to confirm its protective potential against ASFV. Furthermore, it also elicited a robust antibody response, generating high-titer Bac-recombinant protein-specific antibodies. Therefore, these findings suggest that the ASFV Bac-recombinant protein is a promising candidate for a vector-based vaccine. Full article

Oropouche virus (OROV) is an emerging arbovirus responsible for Oropouche fever, also known as sloth fever, a febrile illness that can lead to recurrent outbreaks in affected regions. Endemic to parts of South and Central America, OROV is primarily transmitted by biting midges (Culicoides paraensis), although mounting evidence implicates mosquitoes, particularly the Culex and Aedes species, as additional vectors. Recent ecological disturbances—such as deforestation, urbanization, and climate change—have driven significant shifts in vector population dynamics, contributing to the expanded geographic range and increased transmission of OROV. Notably, recent reports of OROV infections among American and European travelers to Cuba highlight the virus’s growing potential for international dissemination and underscore its significance as a global health concern. OROV is an enveloped orthobunyavirus within the Peribunyaviridae family, possessing a tripartite, single-stranded, negative-sense RNA genome composed of the S (small), M (medium), and L (large) segments. These segments encode the nucleocapsid (N) protein, glycoproteins (Gn and Gc), and RNA-dependent RNA polymerase, respectively. Despite increasing incidence and potential for global spread, no licensed vaccines or antiviral therapies currently exist, and effective diagnostic tools remain limited. Furthermore, although human-to-human transmission has not been observed, the absence of robust surveillance systems complicates timely outbreak detection and response. In this study, we present a comprehensive molecular characterization of OROV’s major structural proteins, with an emphasis on structural modeling and epitope prediction. By integrating bioinformatics approaches with available structural data, we identify key antigenic regions that could serve as targets for the development of serological diagnostics and vaccine candidates. Our findings contribute critical insights into the molecular virology of OROV and provide a foundational framework for future efforts aimed at the prevention, diagnosis, and control of this neglected tropical pathogen. These advancements are essential for mitigating the impact of OROV in endemic regions and reducing the risk of global emergence. Full article

The Nipah virus (NiV) is a zoonotic pathogen characterized by high fatality rates and pandemic potential, whereby there is an urgent need for developing safe and effective vaccines. However, the evaluation of NiV vaccine-induced immunity is hindered by the requirement of Biosafety Level-4 (BSL-4) containment. In this study, we developed a recombinant vesicular stomatitis virus (rVSV)-based pseudovirus-expressing NiV fusion (F) and attachment (G) glycoproteins using a luciferase reporter gene for bioluminescence detection. This pseudovirus was optimized for production in BHK-21 (WI-2) cells, and simultaneous incorporation of NiV-F and NiV-G onto the surface of the pseudotyped virus was confirmed via immunoprecipitation and Western blotting. We evaluated our pseudovirus-based neutralization assay using NiV-F-immunized mouse sera and a commercial anti-NiV-G antibody, confirming robust neutralization by the latter. To establish a BSL-2-compatible model for evaluating in vivo protective efficacy, we performed in vivo imaging, which revealed a marked reduction in the luminescence signal in NiV-G-immunized mice compared to naïve controls, indicating vaccine-induced protection. Our study established an integrated in vitro and in vivo pseudovirus platform using rVSV that enables safe, quantitative, and BSL-2-compatible evaluation of NiV vaccine candidates. This model offers a valuable tool for preclinical screening of vaccine-induced neutralizing antibody responses and protective efficacy. Full article

Visceral leishmaniasis caused by Leishmania donovani is one of the major neglected tropical diseases attributable to parasitic protozoa. In the absence of an effective vaccine, chemotherapy remains the only available therapeutic option. However, current treatments rely on a limited number of drugs that are largely obsolete, highly toxic or require intravenous administration, and their extensive use has led to the emergence of drug resistance. Consequently, the discovery of new antileishmanial agents is an urgent priority. In this study, a commercial library of 449 alkaloids in a high-throughput screening format was evaluated against both axenic bone marrow-derived amastigotes and intramacrophagic amastigotes from mice infected with L. donovani IRFP, a strain engineered to emit infrared fluorescence in its viable form. Six isoquinoline-type alkaloids showed the best antileishmanial efficacy against intramacrophagic amastigotes while exhibiting minimal cytotoxicity toward RAW 264.7 and HepG2 cell lines, with a promising selective index higher than four, and good mouse intestinal tolerance in mouse organoids. Among these compounds, the protoberberine scaffold emerged as the most promising candidate for further drug development. Full article