Search Results (64)

This review describes the cellular and molecular mechanisms underlying multi-dose bacille Calmette-Guérin (BCG) as an investigational immunotherapy for glycemic improvement in autoimmune diabetes. The BCG data is most often human clinical trial data over the last 15 years paired with mechanistic insights. BCG as a vaccine has an excellent safety record with a century-long safety record in tuberculosis prevention worldwide and, for 36 years, has been FDA-approved at higher doses for the treatment of bladder cancer. Our group and others have conducted multiple clinical trials evaluating multi-dose BCG immunotherapy in adults with the two forms of longstanding autoimmune diabetes. In type 1 diabetes (T1D), clinical trials of multi-dose BCG have shown stable repeated reductions in the FDA-recommended biomarker glycated hemoglobin (HbA1c) to near-normal levels (vs placebo) for at least 8 years. This improvement paradoxically occurs without any recovery of pancreatic function from its negligible baseline level. Evidence from long-term trials, together with companion global mechanistic studies, indicates that glycemic improvement is associated with BCG-induced correction of aerobic glycolysis defects in lymphoid and myeloid cells, an outcome also observed in the granuloma of BCG’s close relative, tuberculosis. Restoration of energy metabolism to aerobic glycolysis in diabetic lymphoid cells increases glucose utilization, thereby enhancing systemic glucose uptake from the bloodstream, as demonstrated by longitudinal PET/CT imaging. In contrast, latent autoimmune diabetes in adults (LADA), a form of slow autoimmune diabetes that occurs late into adulthood, has minimal or lacks the clinically significant aerobic glycolysis defect. In LADA with multi-dose BCG immunotherapy glycemic improvement in BCG-treated patients does not occur commonly, based on 8 years of data. LADA nevertheless displays other favorable immune and clinical responses suggestive of BCG-induced regulatory T cell (Treg) induction. In LADA, multi-dose BCG decreases inflammation, thus halting pancreatic autoimmunity with insulin rescue and also halts inflammatory driven insulin resistance. BCG’s consistent clinical benefits in autoimmune diabetes coincide with the gradual pace of upstream epigenetic reprogramming of genes involved in metabolic and T cell pathways without changing genotype. Understanding the mechanistic chain linking BCG-induced epigenetic changes to clinical efficacy may offer insights into the treatment and potential prevention of autoimmune diabetes. Full article

Tuberculosis (TB) and chronic obstructive pulmonary disease (COPD) remain global public health challenges, yet the mechanisms underlying their comorbidity remain poorly understood. COPD is associated with an increased risk of active TB, but the cellular and molecular basis of this association remains unclear. A growing body of evidence suggests that TB is not limited to an intramacrophage infection but is accompanied by a disruption of the local immune balance in lung tissue. This review analyzes the early interface of host–Mycobacterium tuberculosis (Mtb) interaction—from pattern recognition signaling pathways and metabolic reprogramming of macrophages to epithelial barrier responses and the delayed αβ T cell response. This review evaluates γδ T cells, particularly phosphoantigen (pAg)-reactive Vγ9Vδ2 cells, as a candidate early integrative component of the host response, positioned between macrophage infection, epithelial stress, mycobacterial antigens, and bacille Calmette–Guérin (BCG)-induced trained immunity. Available evidence suggests that COPD-associated immune alterations may impair mucociliary clearance, antimicrobial peptide production, phagocytosis, and innate T cell responses while favoring cytotoxic reactions, the IL-17A–G-CSF–neutrophil axis, and protease-mediated tissue damage; however, direct mechanistic evidence in patients with TB–COPD remains limited. It is important to note the differences in data obtained from studies in humans, primates, mice, and in vitro: the Vγ9Vδ2 system has no direct analog in laboratory mice, which represents a key limitation for preclinical studies. A key unresolved question remains the nature and functional consequences of γδ T cell changes in patients with coexisting COPD and TB infection. The answer to this question could inform new strategies for the prevention and treatment of TB in patients with COPD, including BCG revaccination, pAg-mediated immunomodulation, and the development of biomarkers to distinguish between protective and harmful early immune responses. Full article

Mycobacterium bovis Bacille Calmette–Guérin (BCG), the only licensed vaccine against tuberculosis, provides inconsistent protection against pulmonary tuberculosis, reflecting an incomplete understanding of how vaccine-induced immunity is organized within tissues. Emerging evidence indicates that the route of vaccination is not merely a technical variable but a critical determinant of immune programming. Whereas parenteral BCG primarily elicits systemic immune responses, mucosal delivery reprograms immunity at the respiratory interface by promoting localized trained innate immunity, tissue-resident memory T (T_RM) cells, and early containment of infection. In this review, we propose an integrated framework of “immune layering,” in which protection emerges through the coordinated interactions of epithelial regulation, trained innate immunity, tissue-resident adaptive memory, regulatory homeostasis, and systemic immune support across spatial and temporal scales. Within this framework, trained innate immunity serves as an initial conditioning layer that shapes subsequent adaptive differentiation, whereas epithelial- and microbiota-associated regulatory networks establish the tissue context in which immune responses are initiated, organized, and maintained. Importantly, effective mucosal immunity depends on a dynamically regulated equilibrium rather than maximal immune activation. The dissociation between enhanced early pulmonary immune responses and limited long-term protection underscores the influence of tissue-specific regulatory constraints and environmental context on vaccine efficacy. This framework redefines correlates of protection by identifying the vaccination route and tissue-level immune organization as fundamental determinants of protective immunity, thereby providing a conceptual foundation for the rational development of next-generation mucosal tuberculosis vaccines. Full article

Background: In some children with immunodeficiency, Bacille Calmette–Guérin (BCG) vaccination can lead to dissemination and severe infection, including severe intracranial infection, called disseminated BCG disease (BCGosis), which is characterized by high rates of disability and mortality. However, the specific routes by which BCG crosses CNS barriers and the patterns of temporal remodeling of the CNS immune microenvironment during infection have yet to be fully elucidated. Methods: Mice were infected with BCG through tail vein injection to construct an intracerebral mycobacterial infection mouse model, wherein the brain was collected and analyzed using single-cell RNA sequencing. We profiled temporal transcriptomic changes in cell populations, pathways, and cell–cell communication associated with anti-mycobacterial activity and inflammation-induced disturbance of physiological brain activities. Results: After BCG was injected via tail vein, histopathological images and cultured colonies of brain tissue confirmed successful brain infection. Then, whole-brain tissue was dissected for 10× Genomics single-cell sequencing, and we acquired 15 cell types. Dysfunction and inflammatory responses were observed in endothelial and ependymal cells. Infection induced dynamic state transitions in microglia, enabling their differentiation into disease-related and interferon-responsive states. Along with peripheral immune cells, microglia formed temporally structured communication networks that mediated early events such as chemokine recruitment and inflammatory storms, and facilitated late-stage immune checkpoint upregulation. Conclusions: This study proposes BCSFB as a possible pathway of mycobacteria invasion and reveals the temporality of immune response processes in the pathogenesis of intracerebral mycobacterial infection. Full article

Latent tuberculosis infection (LTBI) represents a major global health concern as it constitutes the principal reservoir for future tuberculosis (TB) disease. Its identification is particularly important in Bacille Calmette–Guérin (BCG)-vaccinated populations, where cross-reactivity of purified protein derivative limits the specificity of the tuberculin skin test and hampers targeted preventive therapy. Early Mycobacterium tuberculosis antigens encoded within the RD1 region, especially ESAT-6, CFP-10 and TB7.7, have enabled the development of antigen-specific interferon-gamma release assays (IGRAs) and recombinant skin tests with improved BCG-independent specificity. This narrative review integrates and critically appraises current evidence on the immunobiological properties of early and latency-associated antigens, the cellular mechanisms underlying T-cell-dependent immune reactivity, and the diagnostic performance of IGRAs and ESAT-6/CFP-10-based skin tests, rather than merely summarizing individual studies. Although these platforms rely on different assay principles (in vitro cytokine release versus in vivo delayed-type hypersensitivity), both measure antigen-specific T-cell memory and do not define the biological stage of infection or reliably distinguish latent from incipient or active TB. Across most adult populations, IGRAs demonstrate high specificity and acceptable sensitivity, whereas reduced sensitivity and higher rates of indeterminate results are observed in young children and immunocompromised individuals. ESAT-6/CFP-10-based skin tests show diagnostic accuracy comparable to IGRAs and may offer operational advantages in resource-limited settings. Latency-associated antigens and host biomarkers such as IP-10, together with multi-analyte immune signatures, represent promising avenues for improving diagnostic sensitivity and prognostic stratification but currently lack sufficient validation for routine clinical use. Overall, RD1-encoded antigens remain central to LTBI immunodiagnosis, while future research should focus on developing stage-resolving and prognostic biomarkers, optimized antigen panels, and standardized interpretive frameworks. Full article

Pediatric tuberculosis (TB) remains a critically underrecognized contributor to global childhood morbidity and mortality, with the highest burden concentrated in low-resource settings. Although children comprise a minority of overall TB cases, mortality is disproportionately high, particularly among those under five years of age, driven largely by delayed diagnosis, inadequate linkage to care, and limited access to effective treatment. The continued rise of pediatric multidrug-resistant TB (MDR-TB), especially in regions with low sociodemographic development, further highlights persistent gaps in current control strategies. This review synthesizes key aspects of pediatric TB pathogenesis and host immune responses that predispose young children to rapid disease progression and severe outcomes, including immune immaturity and paucibacillary infection. We summarize pulmonary and extrapulmonary disease manifestations and identify populations at heightened risk, including children with HIV, malnutrition, type 1 diabetes mellitus, and congenital or treatment-related immunosuppression. Ongoing challenges in diagnosis and treatment are discussed, including limitations of existing microbiologic and immunologic tests, specimen collection constraints, regimen toxicity, and barriers to adherence. Prevention remains central to reducing pediatric TB mortality. We highlight the sustained importance of bacille Calmette–Guérin (BCG) vaccination in preventing severe disease and death, the context-dependent variability in vaccine effectiveness, and the structural and socioeconomic determinants of vaccine coverage. We conclude that integrating equitable vaccine delivery, scalable preventive therapy, and child-adapted diagnostic strategies is essential to meaningfully reduce the global pediatric TB burden. Full article

Bacille Calmette-Guérin (BCG) remains the only licensed vaccine against tuberculosis (TB), administered to >100 million neonates annually. It confers approximately 70–80% protection against tuberculous meningitis and miliary TB in early childhood, under-pinning its continued use in high-burden settings. As a live-attenuated vaccine, however, BCG can rarely cause adverse reactions ranging from self-limited local lesions to life-threatening disseminated BCG disease (BCGosis), which almost exclusively occurs in infants with severe primary or acquired immunodeficiencies such as SCID, MSMD, CGD, or symptomatic HIV infection. Implementation of universal newborn screening for severe combined immunodeficiency (SCID) using the T-cell receptor excision circle (TREC) assay now enables prospective identification and deferral of these high-risk neonates, virtually eliminating fatal BCGosis. Here we synthesize global data published since 2010 on the clinical spectrum, immunopathogenesis, and epidemiology of BCG-related complications, highlighting the impact of vaccine substrain, administration technique, and host immune status on adverse-event rates. On the basis of this evidence, we propose a practical, evidence-based risk-assessment checklist (BCG-RAKE) to support safer vaccine deployment while preserving the substantial TB-control benefits of universal BCG immunization. Full article

Background: Tuberculosis (TB) remains a global health priority, with current interventions like the Bacille Calmette–Guérin (BCG) vaccine lacking efficacy against latent infection and drug-resistant strains. Novel vaccines targeting both latent and active TB are urgently needed. Objective: This study aims to design a multi-epitope vaccine (MEV) and evaluate its immunogenicity, structural stability, and interactions with toll-like receptor 2/4 (TLR-2/4) via computational biology approaches. Methods: We designed MEV using bioinformatics tools, prioritizing immunodominant epitopes from Mycobacterium tuberculosis antigens. Structural stability was optimized through disulfide engineering, and molecular docking/dynamics simulations were used to analyze interactions and conformational dynamics with TLR-2/4. Antigenicity, immunogenicity, population coverage, and immune responses were computationally assessed. Results: The MEV candidate, CP91110P, exhibited 86.18% predicted global human leukocyte antigen (HLA)-I/II coverage, high antigenicity (VaxiJen: 0.8789), and immunogenicity (IEDB: 4.40091), with favorable stability (instability index: 33.48) and solubility (0.485). Tertiary structure analysis indicated that 98.34% residues were located in favored regions. Molecular docking suggested strong TLR-2 (−1535.9 kcal/mol) and TLR-4 (−1672.5 kcal/mol) binding. Molecular dynamics simulations indicated stable TLR-2 interactions (RMSD: 6–8 Å; Rg: 38.50–39.50 Å) and flexible TLR-4 binding (RMSD: 2–6 Å; Rg: 33–36 Å). Principal component analysis, free energy landscapes, and dynamic cross-correlation matrix analyses highlighted TLR-2’s structural coherence versus TLR-4’s adaptive flexibility. Immune simulations predicted potential robust natural killer cell activation, T helper 1 polarization (interferon-gamma/interleukin-2 dominance), and elevated IgM/IgG levels. Conclusions: CP91110P is predicted to stably bind to TLR-2 and flexibly interact with TLR-4, with prediction of its high antigenicity and broad coverage across immune populations. However, this conclusion requires confirmation through experimental validation. Therefore, it may provide a promising candidate for experimental validation in the development of tuberculosis vaccines. Full article

Background: The Bacille Calmette–Guérin (BCG) vaccine is part of the Extended Programme on Immunization (EPI) and as such is generally administered at birth. The global introduction of BCG not only protected many vaccinated infants against severe complications of tuberculosis but also resulted in markedly reduced overall childhood mortality. Studies in human adults determined that BCG vaccination induces epigenetic reprogramming of innate immune cells (also known as trained immunity) and can also enhance T cell responses to both mycobacterial and non-mycobacterial antigens. Goal and Methods: The current study tested the hypothesis that BCG immunization similarly impacts the functionally distinct infant immune system. Towards this goal, we applied RNA sequencing to assess transcriptome changes in circulating CD4⁺ T cells of Malawian infants prior to and 2 to 13 weeks after BCG immunization. Results: In the first three months of life, transcriptome changes of infant CD4 T cells implied a functional shift towards T helper 1 and Th17 immunity. Vaccination with BCG resulted in additional modulation of the CD4 T cell transcriptome and differentially expressed genes could be linked to metabolomic function. Conclusions: These findings are consistent with data reported in BCG vaccinated adults and contribute to the understanding of molecular changes in infant CD4 T cells that may explain the improved capacity of the infant immune system to respond to pathogens after BCG vaccination. Full article

Background: Immunotherapy is gaining great relevance in both non-muscle-invasive bladder cancer (NMIBC), with the use of bacille Calmette–Guerin (BCG), and in muscle-invasive BC (MIBC) with anti-checkpoint therapies blocking PD-1/PD-L1, CTLA-4/CD80-CD86, and, more recently, NKG2A/HLA-E interactions. Biomarkers are necessary to optimize the use of these therapies. Methods: We evaluated killer-cell immunoglobulin-like receptors (KIRs) and HLA-I genotyping and the expression of NK cell receptors in circulating T and NK lymphocytes at diagnosis in 325 consecutive BC patients (151 treated with BCG and 174 treated with other therapies), as well as in 648 patients with other cancers and 973 healthy donors as controls. The proliferation and production of cytokines and cytotoxicity were evaluated in peripheral blood mononuclear cells, stimulated in vitro with anti-CD3/CD28 or BCG, from selected patients based on HLA-B −21M/T dimorphism (NKG2A ligands). Results: The HLA-B −21M/T genotype showed opposing results in BC patients treated with BCG or other therapies. The MM genotype, compared to MT and TT, was associated with a longer 75th-percentile overall survival (not reached vs. 68.0 ± 13.7 and 52.0 ± 8.3 months, p = 0.034) in BCG, but a shorter (8.0 ± 2.4 vs. 21.0 ± 3.4 and 19.0 ± 4.9 months, p = 0.131) survival in other treatments. The HLA-B −21M/T genotype was an independent predictive parameter of the progression-free survival (HR = 2.08, p = 0.01) and the OS (HR = 2.059, p = 0.039) of BC patients treated with BCG, together with age and tumor histopathologic characteristics. The MM genotype was associated with higher counts of circulating CD56^bright, fewer KIR2DL1/L2⁺ NK cells, and lower NKG2A expression, but not with differential in vitro NK cell functionality. Conclusions: The HLA-B −21M/T is independently associated with BC patient outcomes and can help to optimize the use of new immunotherapies in these patients. Full article

Background/Objectives: Knowledge of the symptoms and side effects (SSEs) of Bacille Calmette–Guerin (BCG) therapy for non-muscle invasive bladder cancer (NMIBC) is critical when establishing selecting appropriate therapies for patients. The aim of our study was to systematically review the common patient-reported SSEs associated with BCG-based and other intravesical chemotherapy treatment options for NMIBC. Methods: A systematic search of AMED, MEDLINE, EMBASE, PsycINFO, Web of Knowledge, and Scopus was conducted from inception to July 2024. The PRISMA process was followed. Prospective studies with an adult cohort that assessed SSEs through direct patient reports with standardized patient-reported outcome measures were included in this study. A narrative synthesis was performed to compare the frequency of SSEs reported by treatment options. Statistical analysis was performed using chi square and Fisher’s exact tests, with statistical significance at p < 0.05. Results: Thirty-four studies met the eligibility criteria. The main findings indicated that BCG induction is more toxic than BCG induction with maintenance; however, severe SSEs resulting in treatment cessation occurred almost twice as often in patients on BCG induction with maintenance. Patients who received full-dose BCG were more likely to have SSEs compared to those receiving a low dose. BCG monotherapy alone caused more SSEs compared to BCG with chemotherapy. Patients reported more SSEs with BCG compared to chemotherapy alone for induction with maintenance. Limitations of the study include the varied length of maintenance regimes affecting nature of data reported. Conclusions: The findings of this study allow for improved counselling of patients regarding expected side effects in accordance with their recommended treatment options for NMIBC. Full article

Fragment-based drug discovery (FBDD) focuses on small compounds, known as fragments, typically with a molecular weight of less than 300 Da. This study highlights the benefits of employing a pure natural product library for FBDD, contrasting with the predominant use of synthetic libraries. Practical methods for rapidly constructing such libraries from crude extracts were demonstrated across various plant and microbial samples. Twenty-nine (29) natural product fragments, including a new compound (20), were identified. Antimicrobial activities were assessed for a subset of the isolated compounds, revealing potent fragments (MICs 4–8 μg/mL) against Mycobacterium bovis bacille Calmette-Guérin (BCG), Staphylococcus aureus (SA), and methicillin-resistant S. aureus (MRSA). Furthermore, a native mass spectrometry technique was introduced to rapidly identify non-competitive fragments against malarial proteins. As a result, two pairs of non-competitive fragments, lepiotin C (31) and 7-amino deacetoxy cephalosporanic acid (32) binding to dynein light chain 1, methyl gallate (33) and β-santanin (34) binding to dUTPase, were identified, serving as promising starting points for developing potent malarial protein inhibitors. Full article

Tuberculosis, caused by Mycobacterium tuberculosis (M. tuberculosis), remains a formidable global health challenge, affecting a substantial portion of the world’s population. The current tuberculosis vaccine, bacille Calmette–Guérin (BCG), offers limited protection against pulmonary tuberculosis in adults, underscoring the critical need for innovative vaccination strategies. Cytokines are pivotal in modulating immune responses and have been explored as potential adjuvants to enhance vaccine efficacy. The strategic inclusion of cytokines as adjuvants in tuberculosis vaccines holds significant promise for augmenting vaccine-induced immune responses and strengthening protection against M. tuberculosis. This review delves into promising cytokines, such as Type I interferons (IFNs), Type II IFN, interleukins such as IL-2, IL-7, IL-15, IL-12, and IL-21, alongside the use of a granulocyte–macrophage colony-stimulating factor (GM-CSF) as an adjuvant, which has shown effectiveness in boosting immune responses and enhancing vaccine efficacy in tuberculosis models. Full article

Non-muscle-invasive papillary urothelial carcinoma (NMIPUC) of the urinary bladder is the most common type of bladder cancer. Intravesical Bacille Calmette–Guerin (BCG) immunotherapy is applied in patients with a high risk of recurrence and progression of NMIPUC to muscle-invasive disease. However, the tumor relapses in about 30% of patients despite the treatment, raising the need for better risk stratification. We explored the potential of spatial distributions of immune cell subtypes (CD20, CD11c, CD163, ICOS, and CD8) within the tumor microenvironment to predict NMIPUC recurrence following BCG immunotherapy. Based on analyses of digital whole-slide images, we assessed the densities of the immune cells in the epithelial–stromal interface zone compartments and their distribution, represented by an epithelial–stromal interface density ratio (IDR). While the densities of any cell type did not predict recurrence, a higher IDR of CD11c (HR: 0.0012, p-value = 0.0002), CD8 (HR: 0.0379, p-value = 0.005), and ICOS (HR: 0.0768, p-value = 0.0388) was associated with longer recurrence-free survival (RFS) based on the univariate Cox regression. The history of positive repeated TUR (re-TUR) (HR: 4.93, p-value = 0.0001) and T1 tumor stage (HR: 2.04, p-value = 0.0159) were associated with shorter RFS, while G3 tumor grade according to the 1973 WHO classification showed borderline significance (HR: 1.83, p-value = 0.0522). In a multivariate analysis, the two models with a concordance index exceeding 0.7 included the CD11c IDR in combination with either a history of positive re-TUR or tumor stage. We conclude that the CD11c IDR is the most informative predictor of NMIPUC recurrence after BCG immunotherapy. Our findings highlight the importance of assessment of the spatial distribution of immune cells in the tumor microenvironment. Full article

The limited reproducibility of the grading of non-muscle invasive papillary urothelial carcinoma (NMIPUC) necessitates the search for more robust image-based predictive factors. In a cohort of 157 NMIPUC patients treated with Bacille Calmette–Guérin (BCG) immunotherapy, we explored the multiple instance learning (MIL)-based classification approach for the prediction of 2-year and 5-year relapse-free survival and the multiple instance survival learning (MISL) framework for survival regression. We used features extracted from image patches sampled from whole slide images of hematoxylin–eosin-stained transurethral resection (TUR) NPMIPUC specimens and tested several patch sampling and feature extraction network variations to optimize the model performance. We selected the model showing the best patient survival stratification for further testing in the context of clinical and pathological variables. MISL with the multiresolution patch sampling technique achieved the best patient risk stratification (concordance index = 0.574, p = 0.010), followed by a 2-year MIL classification. The best-selected model revealed an independent prognostic value in the context of other clinical and pathologic variables (tumor stage, grade, and presence of tumor on the repeated TUR) with statistically significant patient risk stratification. Our findings suggest that MISL-based predictions can improve NMIPUC patient risk stratification, while validation studies are needed to test the generalizability of our models. Full article