Search Results (59)

Background: Tuberculosis (TB) remains a pressing global health crisis. The inadequate efficacy of the BCG vaccine against adult pulmonary TB underscores the urgent need for novel, effective vaccines. This study aimed to design a novel mRNA vaccine candidate against TB using a rational immunoinformatics approach. Methods: From 13 antigens, >12,000 epitopes were filtered to select 60 optimal peptides (36 CTL, 16 HTL, 8 B-cell), assembled into 25 scaffolds with 49 TLR2/4 agonist configurations. EP9158H underwent structural modeling, 100 ns molecular dynamics, docking, immune simulation, RNAfold, and conservation analysis across 76 strains. Results: EP9158H, encoding 15 CTL, 9 HTL, and 8 B-cell epitopes flanked by TLR2 agonist ESAT-6 and TLR4 agonist HBHA, emerged as the optimal candidate. All 32 constituent epitopes showed >81% conservation, with 81.25% exhibiting perfect identity across MTBC lineages. The scaffold demonstrated high solubility (0.531), broad population coverage (73.76% MHC-I, 88.91% MHC-II), optimal TLR2/4 docking scores (−1359.7 and −1348.3), and robust structural stability (ProSA Z-score −6.18; RMSD 22–27 Å). Immune simulation predicted strong Th1-biased T-cell responses and high levels of antibody titers. RNAfold analysis revealed stable mRNA secondary structures (MFE −1127.5 kcal/mol) supporting efficient translation. Conclusions: EP9158H integrates broad epitope coverage, dual TLR agonism, and validated stability. Compared to single-antigen vaccines, it offers superior strain coverage, enhanced innate activation, and mRNA advantages for CTL induction, warranting experimental validation. Full article

T cells and B cells are central components of the adaptive immune system, orchestrating immune responses through a complex network of interactions. This review explores the dynamic interplay between T and B cells, focusing on their development, activation, and functional coordination in immune defense. T cells provide essential help to B cells through cytokine signaling and direct cell–cell interactions, facilitating antibody production and affinity maturation in germinal centers. Conversely, B cells contribute to antigen presentation and cytokine modulation, influencing T cell differentiation and function. The regulation of these interactions is critical for maintaining immune homeostasis, preventing autoimmunity, and enhancing vaccine efficacy. Dysregulation of T-B cell crosstalk is implicated in various immune disorders, including autoimmune diseases and immunodeficiencies. Recent advances in immunotherapy have targeted these pathways to modulate immune responses in conditions such as cancer, infections, and inflammatory diseases. This review synthesizes current knowledge on T and B cell physiology, highlighting emerging research on their cooperative mechanisms. Full article

Bovine tuberculosis (bTB) is mainly caused by Mycobacterium bovis, which affects cattle, leading to significant economic losses. In Chile, the vaccination with the M. bovis Bacillus Calmette-Guérin (BCG) strain has been implemented in dairy herds with high prevalence of bTB. This study evaluated non-specific protection associated with BCG on the detection of pathogen-associated genes (nsp5, stx1, stx2, invA, IS1081) and mortality related to diarrhea and pneumonia in calves. A total of 186 calves from a commercial dairy farm were enrolled and grouped as vaccinated (n = 96) and non-vaccinated (n = 90). The BCG Russia strain (2–5 × 10⁵ UFC) was inoculated subcutaneously within the first 30 days after birth. Animals were monitored through fecal sampling at 3 and 6 months of age for molecular detection of gene sequences. A logistic regression analysis showed differences in detection rates of the stx1 sequence at 3 months, with a higher risk for the non-vaccinated individuals (OR 2.91, CI 1.42–5.94, p = 0.03) and for those born in the cold season (OR 9.55, CI 2.02–45.11, p = 0.004). A Kaplan–Meier survival analysis showed a significant difference in deaths in vaccinated calves compared with non-vaccinated animals (p = 0.018), suggesting that BCG confers non-specific protection during the first 3 months after birth, in field conditions. Full article

Mycobacterium bovis is the causative pathogen of bovine tuberculosis (bTB), a disease that affects cattle and other mammals, including humans. Currently, there is no efficient vaccine against bTB, underscoring the need for novel immunization strategies. The M72 fusion protein, composed of three polypeptides derived from Mycobacterium tuberculosis and M. bovis, has demonstrated protective efficacy against M. tuberculosis in clinical trials when combined with the AS01E adjuvant. Given the established efficacy of nanocapsule formulations as vaccine delivery systems, this study evaluated a novel immunization strategy combining BCG with either full-length M72 or a truncated M72 fused to a streptococcal albumin-binding domain (ABDsM72). Both antigens were encapsulated in chitosan/alginate nanocapsules and assessed in a murine M. bovis challenge model. Priming with BCG followed by an M72 boost significantly improved splenic protection compared to BCG alone, but it did not enhance pulmonary protection. Notably, boosting with ABDsM72 further increased the proportion of CD4+KLRG1-CXCR3+ T cells in the lungs of M. bovis-challenged mice, a key correlate of protective immunity. These findings demonstrate that chitosan/alginate-encapsulated antigens enhance BCG-induced immunity, supporting their potential as next-generation vaccine candidates for bTB control. Full article

Background/Objectives: The emergence of multidrug-resistant Acinetobacter baumannii (MDR A. baumannii) as a leading cause of fatal hospital-acquired infections underscores the urgent need for effective vaccines. While oral vaccines using live Bacillus subtilis spores expressing A. baumannii TonB-dependent receptor (TBDR) show promise, biosafety concerns regarding recombinant spore persistence necessitate alternative strategies. Here, we evaluated chemically inactivated B. subtilis spores displaying TBDR as a safer yet immunogenic vaccine candidate. Methods: Recombinant spores were inactivated using iron-ethanol sporicidal solution and administered to BALB/c mice (8–12 weeks old) to assess safety and immunogenicity. Toxicity was evaluated through clinical monitoring, serum biochemistry, and histopathology. Immune responses were characterized by T/B cell activation, IgG/IgA titers, and mucosal sIgA levels. Protective efficacy was determined by challenging immunized mice with MDR A. baumannii Ab35 and quantifying bacterial loads and examining tissue pathology. Results: The inactivated spores exhibited an excellent safety profile, with no adverse effects on clinical parameters, organ function, or tissue integrity. Immunization induced robust systemic and mucosal immunity, evidenced by elevated CD4+/CD8+ T cells, B cells, and antigen-specific IgG/IgA in serum and mucosal secretions. Following the challenge, vaccinated mice showed significantly reduced pulmonary bacterial burdens (>90% reduction), and preserved lung and spleen architecture compared to controls, which developed severe inflammation and tissue damage. Conclusions: These findings demonstrate that inactivated B. subtilis spores expressing TBDR are a safe, orally administrable vaccine platform that elicits protective immunity against MDR A. baumannii. By addressing biosafety concerns associated with live spores while maintaining efficacy, this approach represents a critical advance toward preventing high-risk nosocomial infections. Full article

Background: Bovine tuberculosis (bTB) is an infectious disease which causes significant damage to the farming industry and remains a disease of global significance. Although control strategies have focused on a test and cull approach primarily based around specific cell-mediated immune responses, serological assays are increasingly being used as a supplementary test alongside skin testing and interferon-gamma release (IGRA) assays. The UK is moving towards the use of the Bacillus Calmette–Guérin (BCG) vaccination of cattle as an additional targeted control tool against bTB. However, there are concerns over its potential impact on the outcomes of bTB diagnostic tests and other non-TB assays, such as serological tests for Mycobacterium avium subsp. paratuberculosis (MAP). Methods: We investigated the performance of commercially available serology tests designed to detect bTB and MAP using serum samples from BCG-vaccinated animals which were subsequently infected with Mycobacterium bovis (M. bovis). Results: BCG vaccination per se did not significantly impact the specificity of serological diagnostic tests for bTB or Johne’s disease. However, increased numbers of false-positive responses in bTB serology tests were seen in BCG-vaccinated animals 3 weeks following a tuberculin skin test, where up to 23% and 54% of animals gave a positive result in IDEXX and Enferplex tests, respectively. Furthermore, M. bovis infection gave rise to false-positive test results for Johne’s disease, irrespective of the animals’ prior BCG vaccination status. Conclusions: Caution should be taken when assessing results from serology tests for bTB if tuberculin skin testing has occurred shortly before collection of blood from BCG-vaccinated cattle. Furthermore, these results highlight the potential for misdiagnosis of MAP infection when using serology tests in bTB-infected cattle. Full article

Mycobacterium tuberculosis (Mtb) vaccines are designed to prevent infection, prevent reactivation of latent infection, and/or provide adjuvant therapy to standard TB treatment for active Mtb. Emerging vaccine technologies include reverse vaccinology, DNA and RNA vaccines, subunit vaccines, and multi-epitope vaccines. Currently, many different types of vaccine candidates are in clinical trials, though, to date, BCG remains the only approved Mtb vaccine. Mtb has a complex genome with numerous antigens, but not all are equally effective in eliciting immunity, so a critical challenge is the selection of antigens and epitopes that are most likely to induce a long-term, broad-spectrum protective immune response. Multi-epitope vaccines (MEVs) represent a new event horizon in vaccine development. Bioinformatic computer modeling is being used to maximize efficacy and minimalize adverse effects. Although no multi-epitope vaccines have proceeded to in vivo clinical trials, three candidate MEVs have made it through in silico tests. Multi-epitope vaccine candidate PP13138R, containing 13 HTL epitopes, 13 CTL epitopes, and 8 B cell epitopes in addition to both TLR2 and TLR4 agonists, aims to elicit a broad immune response that could address both active and latent Mtb infection. Similarly, immunoinformatic data were used to design and validate another MEV candidate based on the biomarker PE_PGRS17 with four B cell, nine HTL, and six CTL linked epitopes, with a griselimycin sequence as the adjuvant. A third novel prophylactic and therapeutic MEV was developed that targets Ag85A, AG85B, ESAT-6, and CFP-10 proteins with 12 CTL, 25 HTL, and 21 LBL epitopes with a CpG adjuvant. Full article

Tuberculosis (TB) remains a leading cause of mortality, with drug resistance highlighting the need for new vaccine targets. Peptidyl-prolyl isomerase A (PpiA), a conserved Mycobacterium tuberculosis (Mtb) protein, plays a role in bacterial stress adaptation and immune evasion, making it a potential target for immunotherapy. This study uses computational methods to assess PpiA’s antigenicity, structural integrity, and immunogenic potential. The PpiA sequence was retrieved from NCBI and analyzed for antigenicity and allergenicity using VaxiJen, AllerTOP, and AllergenFP. Physicochemical properties were evaluated using ProtParam, and structural models were generated through PSIPRED and SWISS-MODEL. Structural validation was performed with MolProbity, QMEANDisCo, and ProSA-Web. B-cell epitopes were predicted using BepiPred 2.0 and IEDB, while T-cell epitopes were mapped via IEDB’s MHC-I and MHC-II tools. Epitope conservation across Mtb strains was confirmed using ConSurf. Results indicate PpiA is highly antigenic, non-allergenic, and stable, with several immunogenic epitopes identified for both B- and T-cells. This study supports PpiA as a promising immunogenic target for TB vaccine development. Full article

Background: Echinococcus granulosus represents a significant threat to animal husbandry and human health, but its consequences are often underestimated. Vaccination can prevent E. granulosus infection. We investigated the immune protective effect induced by the recombinant protein P29 of E. granulosus (rEg.P29) peptide vaccine. Methods: The CD4⁺ T-, CD8⁺ T-, Treg-, and CD8⁺CD107a⁺ T-cell proportions in the spleen and peripheral blood of infected mice were analyzed using flow cytometry. Additionally, we measured the proportions of IFN-γ and IL-2 secreted by memory T cells, CD19⁺CD138⁻B cells, CD19⁺CD138⁺ plasmablasts, CD19⁻CD138⁺ plasma cells, and CD19⁺IgD⁻IgG⁺ and CD19⁺IgD⁻IgA⁺ memory B cells. Results: No significant differences were noted in CD4⁺ T-, CD8⁺ T-, and CD8⁺CD107a⁺ Treg-cell percentages among the experimental groups. However, IFN-γ, IL-2, and TNF-α levels and vaccine-specific antibody concentrations in the plasma were significantly elevated in the rEg.P29_T+B + CpG + infection and rEg.P29 + CpG + infection groups compared to those in the PBS + infection and CpG + infection groups. Similarly, CD19⁻CD138⁺ plasma cell and CD19⁺IgD⁻IgG⁺ and CD19⁺IgD⁻IgA⁺ memory B-cell populations, along with specific antibodies, were significantly higher in these groups. Especially, the average cyst burden in the rEg.P29_T+B + CpG + infection and rEg.P29 + CpG + infection groups was significantly reduced compared to that in the PBS + infection and CpG + infection groups. Conclusions: Synthetic peptide vaccines targeting rEg.P29 can effectively inhibit cysts, offering a novel strategy for the development of vaccines against E. granulosus. These findings provide a foundation for further research on the immunogenicity and protective efficacy of rEg.P29-based vaccines. Full article

Tuberculosis (TB) remains a major cause of ill health and one of the leading causes of death worldwide, with about 1.25 million deaths estimated in 2023. Control measures have focused principally on early diagnosis, the treatment of active TB, and vaccination. However, the widespread emergence of anti-tuberculosis drug resistance remains the major public health threat to progress made in global TB care and control. Moreover, the Bacillus Calmette–Guérin (BCG) vaccine, the only licensed vaccine against TB in children, has been in use for over a century, and there have been considerable debates concerning its effectiveness in TB control. A multi-epitope vaccine against TB would be an invaluable tool to attain the Global Plan to End TB 2023–2030 target. A rational approach that combines several B-cell and T-cell epitopes from key lipoproteins was adopted to design a novel multi-epitope vaccine candidate. In addition, interactions with TLR4 were implemented to assess its ability to elicit an innate immune response. The conservation of the selected proteins suggests the possibility of cross-protection in line with the One Health approach to disease control. The vaccine candidate was predicted to be both antigenic and immunogenic, and immune simulation analyses demonstrated its ability to elicit both humoral and cellular immune responses. Protein–protein docking and normal-mode analyses of the vaccine candidate with TLR4 predicted efficient binding and stable interaction. This study provides a promising One Health approach for the design of multi-epitope vaccines against human and livestock tuberculosis. Overall, the designed vaccine candidate demonstrated immunogenicity and safety features that warrant further experimental validation in vitro and in vivo. Full article

Background/Objectives: Vaccines may improve the control and eradication of bovine tuberculosis. However, the evaluation of experimental candidates requires the assessment of the protection, excretion, transmission and biosafety. A natural transmission trial among likely infected animals was conducted. Methods: Seventy-four male heifers were randomly distributed (five groups) and vaccinated subcutaneously with attenuated strains (M. bovis Δmce2 or M. bovis Δmce2-phoP), a recombinant M. bovis BCG Pasteur (BCGr) or M. bovis BCG Pasteur. Then, they cohoused with a naturally infected bTB cohort under field conditions exposed to the infection. Results: A 23% of transmission of wild-type strains was confirmed (non-vaccinated group). Strikingly, first vaccination did not induce immune response (caudal fold test and IFN-gamma release assay). However, after 74 days of exposure to bTB, animals were re-vaccinated. Although their sensitization increased throughout the trial, the vaccines did not confer significant protection, when compared to the non-vaccinated group, as demonstrated by pathology progression of lesions and confirmatory tools. Besides, the likelihood of acquiring the infection was similar in all groups compared to the non-vaccinated group (p > 0.076). Respiratory and digestive excretion of viable vaccine candidates was undetectable. To note, the group vaccinated with M. bovis Δmce2-phoP exhibited the highest proportion of animals without macroscopic lesions, compared to the one vaccinated with BCG, although this was not statistically supported. Conclusions: This highlights that further evaluation of these vaccines would not guarantee better protection. The limitations detected during the trial are discussed regarding the transmission rate of M. bovis wild-type, the imperfect test for studying sensitization, the need for a DIVA diagnosis and management conditions of the trials performed under routine husbandry conditions. Re-vaccination of likely infected bovines did not highlight a conclusive result, even suggesting a detrimental effect on those vaccinated with M. bovis BCG. Full article

The development of a tuberculosis (TB) vaccine is imperative. Employing multi-stage Mycobacterium tuberculosis (Mtb) antigens as targeted antigens represents a critical strategy in establishing an effective novel TB vaccine. In this investigation, we evaluated the immunogenicity and protective efficacy of a recombinant adenovirus vaccine expressing two fusion proteins, Ag85B-ESAT6 (AE) and Rv2031c-Rv2626c (R2), derived from multi-stage antigens of Mtb via intranasal administration in mice. Intranasal delivery of Ad-AE-R2 induced both long-lasting mucosal and systemic immunities, with a preferential elicitation of CD8⁺ T cell immunity demonstrated by the accumulation and retention of CD8⁺ T cells in BALF, lung, and spleen, as well as the generation of CD8⁺ TRM cells in BALF and lung tissues. Compared to subcutaneous immunization with Bacillus Calmette-Guerin (BCG), Ad-AE-R2 provided superior protection against high-dose intratracheal BCG challenge, specifically within the lungs of mice. Our findings support the notion that empowering T cells within the respiratory mucosa is crucial for TB vaccine development while highlighting targeting CD8⁺ T cell immunity as an effective strategy for optimizing TB vaccines and emphasizing that eliciting systemic memory immunity is also vital for the successful development of a TB mucosal vaccine. Furthermore, our results demonstrate that the BCG challenge serves as a convenient and efficient method to evaluate candidate vaccine efficacy. Full article

There is an urgent need for an effective TB vaccine capable of controlling both acute and chronic Mycobacterium tuberculosis infection in populations with diverse genetic backgrounds. In this study, we characterised the immunogenicity and protective efficacy of a novel protein-in-adjuvant subunit vaccine. The protein component is a fusion protein of three different M. tuberculosis antigens, which we termed CysVac5: CysD, a major component of the M. tuberculosis sulfate activation pathway that is highly expressed during the chronic stage of M. tuberculosis infection, is fused with two major secreted mycobacterial antigens, Ag85B and MPT83. Vaccination of C57BL/6 mice with CysVac5, formulated in a monophosphoryl lipid A (MPLA) and dimethyldioctadecylammonium (DDA) adjuvant combination, resulted in the potent generation of polyfunctional CD4⁺ T cells secreting multiple cytokines, including IFN-γ, IL-2, TNF and IL-17, against each of the three components of the fusion protein. Furthermore, vaccination with CysVac5-MPLA/DDA conferred significant protection against infection in mouse lungs, which was greater than that afforded by BCG at extended time points post-challenge. The generation of antigen-specific and protective immunity was also observed in CysVac5 vaccinated BALB/c mice, indicating the vaccine could display efficacy across multiple genetic backgrounds. These results indicate that the CysVac5 vaccine has broad immunogenicity, is effective in controlling both acute and chronic phases of M. tuberculosis infection in mice, and warrants further investigation to assess its potential to control pulmonary TB. Full article

Since their conception with the smallpox vaccine, vaccines used worldwide have mitigated multiple pandemics, including the recent COVID-19 outbreak. Insightful studies have uncovered the complexities of different functional networks of CD4 T cells (T helper 1 (Th1); Th2, Th17) and CD8 T cells (T cytotoxic; Tc), as well as B cell (B^IgM, B^IgG, B^IgA and B^IgE) subsets, during the response to vaccination. Both T and B cell subsets form central, peripheral, and tissue-resident subsets during vaccination. It has also become apparent that each vaccination forms a network of T regulatory subsets, namely CD4+ CD25+ Foxp3⁺ T regulatory (Treg) cells and interleukin-10 (IL-10)-producing CD4+ Foxp3⁻ T regulatory 1 (Tr1), as well as many others, which shape the quality/quantity of vaccine-specific IgM, IgG, and IgA antibody production. These components are especially critical for immunocompromised patients, such as older individuals and allograft recipients, as their vaccination may be ineffective or less effective. This review focuses on considering how the pre- and post-vaccination Treg/Tr1 levels influence the vaccination efficacy. Experimental and clinical work has revealed that Treg/Tr1 involvement evokes different immune mechanisms in diminishing vaccine-induced cellular/humoral responses. Alternative steps may be considered to improve the vaccination response, such as increasing the dose, changing the delivery route, and/or repeated booster doses of vaccines. Vaccination may be combined with anti-CD25 (IL-2Rα chain) or anti-programmed cell death protein 1 (PD-1) monoclonal antibodies (mAb) to decrease the Tregs and boost the T/B cell immune response. All of these data and strategies for immunizations are presented and discussed, aiming to improve the efficacy of vaccination in humans and especially in immunocompromised and older individuals, as well as organ transplant patients. Full article

One of the most serious diseases affecting dairy cattle, causing significant losses both in breeding and economy, is mastitis, an inflammation of the mammary gland. Due to the economic importance of this issue, many research teams are striving to develop an easy-to-apply and, most importantly, effective method to prevent mastitis. The use of traditional methods for mastitis detecting and treating, as well as improvement in hygienic conditions, have not yielded the expected results in combating this disease combating. Currently, the main task is to find the tools that would allow for the rapid detection of mastitis and the improvement of udder health in cows while maintaining high milk production, which is essential for the profitability of dairy cattle farming. Accurate and rapid diagnostic tools, with the simultaneous capability of identifying pathogens, may help to reduce losses. Sufficient sensitivity and specificity for tests are required to minimize the number of false-positive and false-negative cases. Efforts are also being made to determine the optimal threshold value for detecting the disease at its earliest possible stage. The estimation of somatic cell count (SCC) as a phenotypic indicator of mastitis is widely used. A more precise parameter for accurately describing udder health is the differential somatic cell count (DSCC). The well-known California Mastitis Test (CMT) is an inexpensive, easy, and rapid method for mastitis detection useful on farms. The latest diagnostic methods for mastitis utilize tests based on the activity of N-acetyl-β-d-glucosaminidase (NAGase) or lactate dehydrogenase (LDH) as well as the determination of acute phase proteins (APPs) in blood serum and milk (such as haptoglobin, serum amyloid A, fibrinogen, and ceruloplasmin). Research also focuses on the genomic improvement of mastitis resistance in successive generations, and for this purpose, many quantitative trait loci (QTLs) and single nucleotide polymorphisms (SNPs) have been identified. In recent years, immunotherapy has become an increasingly common area of research, including vaccinations, T/B cell immunotherapy, RNA immunotherapy, epigenetic immunotherapy, stem cell therapy, and native secretory factors. An important aspect of the control of mastitis is the implementation of strategies that focus primarily on preventing the disease through appropriate breeding and farm management practices. In the forthcoming years, a significant challenge will be the development of universal diagnostic and therapeutic strategies that can be effectively implemented as alternatives to antibiotic therapy. Future research should prioritize the advancement of preventive and therapeutic techniques, such as immunotherapies, bacteriocins, herbal therapy, and nanoparticle technology. Full article