Aug 2026· Brazilian Journal of Microbiology· Vol 57· 0 citations· 13 references
Medicine
TL;DR
Through multi-omics integration analysis, this study successfully identified a novel candidate antigen, BMEI1943, with strong Th1-type immunogenicity, providing an experimental basis for the development of safe and efficient subunit vaccines against brucellosis.
Abstract
Brucellosis is one of the most severe Class B infectious diseases prevalent in the agricultural and pastoral areas of northern China. Current attenuated live vaccines (e.g., M5, S19) have defects such as residual virulence, causing abortion in pregnant animals, and the inability to differentiate between natural infection and vaccination (DIVA). Relying on the ABSL-3 laboratory of the Inner Mongolia Center for Disease Control and Prevention, this study established a chronic infection model in C57BL/6J mice using the virulent strain Brucella melitensis M16. Single-cell transcriptome sequencing (10x Genomics) was employed to map the heterogeneity of splenic immune cells. Whole-genome scanning and pangenomic analysis were performed on four strains with different virulence levels (M16, 544 A, M5, 104 M) using second-generation sequencing. Membrane/secreted proteins unique and conserved in virulent strains were screened as candidate antigens, prepared via prokaryotic expression systems, and their humoral and cellular immune levels were detected by indirect ELISA and flow cytometry. A stable chronic infection model was successfully constructed (bacterial load Log10 CFU > 4.5). Single-cell sequencing yielded 45,231 cells, annotated into 12 immune cell subpopulations, revealing significant expansion of Effector CD4 + T cells (P < 0.01) and high expression of the Ifng gene. Pangenomic analysis identified three candidate antigens (BMEI0021, BMEI1943, BMEI0367) that are 100% conserved in virulent strains but absent in the vaccine strain M5. Immunogenicity assays showed that BMEI1943 induced high levels of IgG2a subtype antibodies (titer Log2 13.45 ± 0.52) and IFN-γ + CD4 + T cell responses (frequency 15.80% ± 2.10%). Through multi-omics integration analysis, this study successfully identified a novel candidate antigen, BMEI1943, with strong Th1-type immunogenicity, providing an experimental basis for the development of safe and efficient subunit vaccines against brucellosis.
Vibrio alginolyticus is an opportunistic marine pathogen that causes severe vibriosis in aquatic animals and occasionally in humans, leading to substantial economic losses in aquaculture. Despite progress in antimicrobial therapy, the emergence of multidrug-resistant (MDR) strains and the lack of effective vaccines have emphasized the need for novel approaches. The objective of this study was to identify and assess vaccine candidates in V. alginolyticus ATCC 17749 using an integrative strategy that integrates reverse vaccinology and immune-informatics. The complete proteome of V. alginolyticus ATCC 17749 was retrieved from NCBI databases, and computational pipelines were used to predict subcellular localization, transmembrane topology, and antigenicity. Surface-exposed, non-allergenic and non-toxic outer membrane and secretory proteins with high antigenicity scores were selected for epitope prediction. Cytotoxic T lymphocyte (CTL), helper T lymphocyte (HTL), and B-cell epitopes were identified through NetMHCpan 4.1, IEDB, and ABCpred, respectively. Robust humoral and cellular immune responses were predicted by immune simulation. The target proteins were docked with TLR2 and TLR4 using HDOCK, and the simulation was performed using the iMODS server for the highest-scoring docking complex for each receptor. In silico cloning to express the target protein was performed using the SnapGene tool. This integrated computational vaccinology approach reliably identifies promising antigenic targets for V. alginolyticus, providing a foundation for the rational development of next-generation polyvalent vaccines against Vibrio infections in aquaculture and related fields.
Y. Kumar, Anusha Suresh, Vandana Rajshree et al.· Journal of Pure and Applied...· 0 citations
Infectious coryza (IC) is a respiratory disease of chickens caused by the bacterial primary pathogen
Avibacterium paragallinarum
(AP). Clinical signs are characteristic and suggestive of the disease; however, diagnosis is confirmed through bacterial isolation or qPCR detection. Recently, several naïve, healthy layer (NHL) flocks, neither exposed to IC nor vaccinated against it, tested positive using current IC-specific qPCR assays. Moreover, AP isolates were recovered from these NHL flocks and were designated “non-pathogenic
Avibacterium paragallinarum
” (npAP) due to the absence of clinical signs in the field and in an experimental challenge study. However, understanding the genetic basis behind this difference in pathogenicity remains unknown. Therefore, the purpose of the current study was to investigate the genetic explanations for the lack of pathogenicity in npAP. Comprehensive comparative genomic analysis was performed for 14 npAP and 87 pathogenic AP (pAP) genomes at three main levels, (a) gene presence/absence, (b) sequence variation within translated open reading frames (ORFs) across the whole genome, and (c) targeted analysis of selected virulence-associated genes. The analysis revealed four consistent features, (1) The
HMTp210
gene, encoding the trimeric autotransporter adhesin HMTp210, important for serotyping and protective immunity, is 2–3 times longer in npAP compared to pAP. (2) npAP isolates exhibit either complete absence of the capsular polysaccharide locus or defective genes within the locus. (3) All npAP isolates lack both
hmp
and
nsrR
, which encode Flavohemoglobin/Nitric oxide dioxygenase protein (Hmp) and the nitrite-sensitive transcriptional repressor protein (NsrR), respectively. (4) The
ftsZ
gene, which is essential for cell-division, exhibits substantial allelic divergence between npAP and pAP. We hypothesize that defects or changes in HMTp210 adhesin, capsule, the nitric oxide dioxygenase system, or FtsZ contribute to the nonpathogenic phenotype of npAP in chickens. Moreover, most of npAP isolates encode a putative sialylated lipooligosaccharide which may promote a more commensal-like interaction with the host immune system, preventing an overt inflammatory response. In conclusion, our findings highlight potential virulence factors that can be involved in AP pathogenesis. Additionally, defining and understanding the role of these potential virulence factors, may open new avenues for the development of modified live vaccines against IC.
Mostafa M. S. Shelkamy, S. Schmitz-Esser, Amro Hashish et al.· Frontiers in Microbiology· 0 citations
Brucellosis remains one of the most prevalent zoonotic diseases worldwide, causing substantial economic losses and significant human morbidity. Despite decades of research, no licensed human vaccine against Brucella infection exists, and current veterinary vaccines exhibit considerable safety limitations including residual virulence, pregnancy complications, and diagnostic interference. Here we report the development of a multi-epitope messenger RNA (mRNA) vaccine candidate targeting Brucella melitensis, the most pathogenic species responsible for human brucellosis. Using an integrated immunoinformatics pipeline, we screened ten outer membrane proteins (OMPs) and identified Omp25, Omp31, and BP26 as the most immunodominant antigens. A fusion construct incorporating 24 HLA class I and 31 HLA class II predicted epitopes achieved 87.3% global HLA population coverage. Codon optimization improved the codon adaptation index from 0.55 to 0.93. Molecular dynamics simulations over 200 ns confirmed structural stability of the vaccine-TLR4 complex, with a binding free energy of -65.7 kcal/mol. In vitro assays demonstrated robust Th1-biased immune activation, with IFN-gamma reaching 125.6 pg/mL. In a BALB/c mouse challenge model, the mRNA vaccine conferred 80.0% protection, comparable to the live-attenuated S19 vaccine (92.3%) but without associated safety risks. These findings establish a promising platform for Brucella vaccine development warranting further evaluation in large animal models and human clinical trials.
Zhi-Heng Dong, Sha Li, Jiarong Guo et al.· Research in Veterinary Scien...· 0 citations
Introduction Toxoplasma gondii can cause toxoplasmosis. It is an important type of pathogen within the broad category of emerging and re-emerging zoonoses. As an infectious disease featuring a complex multi-host transmission cycle, it poses an increasingly severe threat to global public health. No licensed vaccines are currently available for pets and humans, and thus a novel high-efficiency vaccine is urgently required. Methods Six antigens (GRA1, MIC17A, OWP2, LEA880, LEA870, and a hypothetical protein LEA530) representing different stages of the parasite lifecycle were selected from ToxoDB. T-cell and B-cell epitopes were predicted using immunoinformatics tools and screened based on antigenicity, allergenicity, and toxicity. The multi-epitope peptide (MEP1) was evaluated using molecular docking with Toll-like receptor 4 (TLR4) and immune simulation. The optimized sequence was expressed in HEK293T cells as a recombinant plasmid (MEP1-pcDNA3.1) and further evaluated in BALB/c mice. Results MEP1 contained 13 cytotoxic T lymphocyte epitopes, 16 helper T lymphocyte epitopes, and 12 B-cell epitopes, with a length of 732 amino acids and a predicted molecular weight of 75.73 kDa. The antigenicity score was 0.7343, and structural modeling indicated stable secondary and tertiary conformations. Molecular docking suggested strong binding affinity to TLR4. Immune simulation predicted increased B-cell and T-cell responses following vaccination. In vivo, MEP1-pcDNA3.1 immunization significantly increased serum IFN-γ levels (526.81 pg/mL) compared with PBS and pcDNA3.1 controls. Splenocyte proliferation was significantly enhanced in the MEP1-pcDNA3.1 group (SI = 1.58 ± 0.21) compared with PBS (1.10 ± 0.09) and pcDNA3.1 (1.12 ± 0.04) groups (P < 0.01). Following challenge with 5 × 10³ tachyzoites of the PLK strain, survival was markedly prolonged in vaccinated mice, whereas all control mice died within 2–4 days. Conclusion This study demonstrates an immunoinformatics-guided multi-epitope vaccine strategy against T. gondii, supported by in vivo immunogenicity and partial protective efficacy in a mouse model.
Wen-Yong Feng, Lu Sun, Chenglong Yang et al.· Frontiers in Immunology· 0 citations
Avian coccidiosis is a severe parasitic disease caused by infection with species of the genus Eimeria, among which Eimeria tenella (E. tenella) is one of the most pathogenic. This study aimed to evaluate the protective efficacy of recombinant subunit vaccine candidates based on E. tenella apical membrane antigen 1 (EtAMA1) and surface antigen 13 (EtSAG13) against E. tenella infection in chickens. To this end, the EtAMA1 and EtSAG13 genes were cloned, the regions encoding the predicted signal peptides and transmembrane domains were removed, the sequences were optimized, and the resulting fragments were inserted into the pET-28a(+) vector. The recombinant subunit vaccine candidates rEtAMA1, rEtSAG13, and rEtAMA1-SAG13 were successfully constructed, and the corresponding recombinant proteins were expressed. Subsequently, animal experiments were conducted to evaluate the immunoprotective effects of the recombinant proteins at different doses (50 and 100 μg). The results showed that all three recombinant proteins were specifically recognized by sera from chickens infected with E. tenella and by polyclonal antibodies prepared in the laboratory. The group immunized with 50 μg rEtAMA1-SAG13 showed the greatest protective effect, with an anticoccidial index (ACI) of 175.48, indicating moderate anticoccidial efficacy. Histopathological analysis further revealed that cecal lesions were significantly alleviated in the immunized groups. Furthermore, serum levels of specific antibodies (IgG and IgY) and cytokines (IL-2, IL-6, IL-17, and IFN-γ) were significantly higher in the immunized groups than in the unimmunized group (P < 0.05). In conclusion, the recombinant subunit vaccine candidate combining EtAMA1 and EtSAG13 provides effective immune protection against E. tenella infection and holds promise for the prevention and control of chicken coccidiosis.
Shuying Zhu, Hui Wang, Yao Liu et al.· Poultry Science· 0 citations
Simple Summary Toxoplasmosis, caused by the zoonotic parasite Toxoplasma gondii, is a major concern for immunocompromised individuals and the livestock industry. Research has shown that AP2X-1 is important for growth, conversion between tachyzoites and bradyzoites, and sexual stage development of T. gondii. In the present study, we found that all mice infected with the PruΔap2X-1 knockout strain survived even at the highest dose (5 × 106 tachyzoites), and no brain cysts were detected. Vaccinated mice were fully protected against both acute disease caused by the type II Pru and ToxoDB#9 PYS strains, and chronic infection induced by tissue cysts, whereas vaccinated mice had modestly extended survival time without conferring complete protection against challenge with the highly virulent RH strain. Moreover, vaccination induced a strong Th1-biased cellular and humoral immune response. Thus, PruΔap2X-1 represents a potential live-attenuated vaccine candidate against toxoplasmosis, with a favorable safety profile observed under the experimental conditions.
Wen-Bo Hao, Li-Xiu Sun, Ru-Shi Tu et al.· Animals· 0 citations
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