Bacillus Calmette-Guerin (BCG) Vaccine Impact on Dementia Risk in Bladder Cancer Patients: A Systematic Review and Meta-Analysis.

BACKGROUND: The BCG vaccine has been traditionally administered to prevent TB. It has been additionally used in bladder cancer patients as a therapy with success. Some observational studies found that bladder cancer patients receiving BCG may have reduced dementia risk, however, the evidence is not conclusive. OBJECTIVE: To investigate the impact of BCG vaccine on dementia risk in bladder cancer patients. METHODS: Six databases were searched from inception to January 13, 2024, for published and unpublished studies that examine the association between BCG and dementia risk in bladder cancer patients. We conducted meta-analyses using a random-effects model. RESULTS: Eight retrospective cohort studies were included in the systematic review and seven in the meta-analyses. Because there were studies with overlapping populations, two separate main analyses were performed reassuring the avoidance of overlap. The first analysis showed that compared to controls, BCG did not reduce dementia risk [5 studies pooled, n=88,852, HR = 0.65, 95% CI (0.40, 1.06), I2 = 85%] whereas there was a marginally significant risk reduction in the second analysis [6 studies pooled, n=70,025, HR = 0.63, 95% CI (0.40, 0.97), I2 = 83%]. Sensitivity analysis excluding the unpublished studies did not affect the outcome importantly. Additional meta-analysis showed that BCG did not reduce the risk of Alzheimer's disease. CONCLUSION: This meta-analysis of observational studies found that BCG administration in bladder cancer patients has likely a minimally positive impact on dementia risk if any. To better understand the effect of BCG on dementia, randomized controlled trials are needed.

Impact of Bacille Calmette-Guérin vaccination on the therapeutic schedule of infantile epileptic spasms syndrome: A 25-year Japanese single-center survey.

Adrenocorticotropic hormone (ACTH) therapy is effective for infantile epileptic spasms syndrome (IESS) but can induce immunosuppression. In Japan, Bacille Calmette-Guérin (BCG) vaccination, modified in 2013 to reduce osteitis/osteomyelitis risk, coincides with the peak onset age of IESS. This raises concerns about infection risks when administering ACTH therapy post-vaccination. To evaluate the impact of BCG vaccination timing on treatment decisions, we retrospectively reviewed the medical records of 86 IESS patients at our hospital (1996-2020). Infants who received ACTH therapy within eight weeks of BCG vaccination experienced no serious adverse events. Four patients deferred or opted out of ACTH therapy, with seizure remission taking 2-15 weeks. The overlap between IESS onset and BCG vaccination period presents clinical challenges in determining the appropriate timing for ACTH therapy. Further epidemiological and immunological research is needed to clarify the relationship between ACTH therapy and BCG-associated adverse events and to optimize treatment strategies and vaccination schedules.

Suppressive effects of Toll-Like Receptor 2, Toll-Like Receptor 4, and Toll-Like Receptor 7 on protective responses to Mycobacterium bovis BCG from epithelial cells.

Mycobacteria have several mechanisms for evasion of protective responses mounted by the host. In this study, we unravel yet another mechanism that is mediated by Toll-Like Receptors TLR2, TLR4, and TLR7 in epithelial cells. We show that mycobacterial infection of epithelial cells increases the expression of TLR2, TLR4, and TLR7. Stimulation of either TLR along with mycobacterial infection results in an inhibition of oxidative burst resulting in increased survival of mycobacteria inside epithelial cells. TLR stimulation along with mycobacterial infection also inhibits activation of epithelial cells for T cell responses by differentially regulating the activation of ERK-MAPK and p38-MAPK along with inhibition of co-stimulatory molecule CD86 expression. Furthermore, stimulation of either TLR inhibits the induction of apoptosis and autophagy. Knockdown of either TLR by specific siRNAs reverses the inhibition by ROS and apoptosis by mycobacteria and results in reduced intracellular survival of mycobacteria in a MyD88-dependent manner. These results point towards a negative role for TLR2, TLR4, and TLR7 in regulating protective responses to M. bovis BCG infection in epithelial cells.

Safety profile of BCG revaccination for COVID prevention among elderly individuals in India.

BCG vaccination is known to be safe in infants and a part of immunization schedule in high tuberculosis (TB) burden countries. In the conquest to bring down the severity of the COVID 19 pandemic, many drugs were repurposed in research mode including BCG vaccination/revaccination in various populations. We did a study among the elderly population (>60 years of age) to assess the role of BCG revaccination in preventing the severity of COVID 19 disease. Live attenuated BCG vaccine was given to the willing participants and were followed up for 6 months to estimate COVID19 incidence, understand severity and immunogenicity profile. A total of 48 serious adverse events (SAE) were reported among 1566 elders, none of them had more than one SAE. None of the SAEs were related to the BCG revaccination. Among the 372 adverse events reported, 96% were local reactions at the vaccine site and resolved on its own. BCG revaccination appeared to be safe and could be explored further if repurposing studies were planned for other diseases.

TB prevention and immunization in pediatrics.

Tuberculosis (TB) is one of the main contributors to global mortality and morbidity. Prevalence of TB is more in developing countries. It is one of the airborne diseases that has always been a major health problem. It is caused by organisms of the Mycobacterium tuberculosis (MTB) complex affecting different organ systems. The proverb prevention is better than cure best applies to TB and it has been practiced from ancient periods. However, modalities of prevention have varied much depending upon the advancement in research and technology. TB preventive practice reduces the load of TB significantly and it was used as the theme for world TB Day for the year 2013. Bacille Calmette-Guérin (BCG) vaccination is one of the modalities to prevent TB and it's been practiced for decades with a lot of modifications from synthesis, schedule and method of administration. BCG mainly prevents serious TB with a less known effect on TB prevention. Other uses of BCG vaccination are being studied. In the modern era, heterologous effects of BCG vaccination have brought BCG once again into the limelight. TB prevention strategies start from basic health education and vaccination. Newer vaccines are under trial to improve the efficacy of TB vaccination and yet to be used for general practice. Prevention and immunization against TB have been modified in immunocompromised children. The concept of drug resistance has to be kept in mind before using anti tubercular drugs without any bacteriological evidence for tuberculosis. National Tuberculosis Elimination Programme (NTEP) focuses on contact tracing and treatment of latent TB infection as a resort to prevent further spread of TB in India. This review article has been authored following an exhaustive examination of the existing literature, with the aim of enhancing comprehension regarding tuberculosis prevention and immunization.

Tuberculosis vaccine - A timely analysis of the drawbacks for the development of novel vaccines.

The BCG vaccine, Bacille Calmette Guerin, holds the distinction of being the most widely administered vaccine. Remarkably, a century has passed since its discovery; however, puzzlingly, questions persist regarding the effectiveness of the immune response it triggers. After years of diligent observation, it has been deduced that BCG imparts immunity primarily to a specific age group, namely children. This prompts a significant query: the rationale behind BCG's limited efficacy against TB in particular age groups and populations remains elusive. Beyond vaccinations, drug therapy has emerged as an alternative route for TB prevention. Nonetheless, this approach faces challenges in the contemporary landscape, marked by the emergence of new instances of MDR-TB and XDR-TB, compounded by the financial burden of treatment. It's noteworthy that BCG remains the sole WHO-approved vaccine for TB. This comprehensive review delves into several aspects, encompassing the immune response during infection, the shortcomings of BCG in conferring immunity, and the various factors contributing to its limitations. Within this discourse, we explore potential explanations for the observed deficiencies of the BCG vaccine and consider how these insights could catalyze the development of future vaccines. The current landscape of novel vaccine development for TB is illuminated, including a spotlight on the latest vaccine candidates.

A second-generation recombinant BCG strain combines protection against murine tuberculosis with an enhanced safety profile in immunocompromised hosts.

Bacille Calmette-Guérin (BCG) remains the only licensed vaccine against tuberculosis (TB). While BCG protects against TB in children, its protection against pulmonary TB in adults is suboptimal, and the development of a better TB vaccine is a global health priority. Previously, we reported two recombinant BCG strains effective against murine TB with low virulence and lung pathology in immunocompromised mice and guinea pigs. We have recently combined these two recombinant BCG strains into one novel vaccine candidate (BCGΔBCG1419c::ESAT6-PE25SS) and evaluated its immunogenicity, efficacy and safety profile in mice. This new vaccine candidate is non-inferior to BCG in protection against TB, presents reduced pro-inflammatory immune responses and displays an enhanced safety profile.

Mtb specific HLA-E restricted T cells are induced during Mtb infection but not after BCG administration in non-human primates and humans.

Novel vaccines targeting the world's deadliest pathogen Mycobacterium tuberculosis (Mtb) are urgently needed as the efficacy of the Bacillus Calmette-Guérin (BCG) vaccine in its current use is limited. HLA-E is a virtually monomorphic unconventional antigen presentation molecule and HLA-E restricted Mtb specific CD8+ T cells can control intracellular Mtb growth, making HLA-E a promising vaccine target for Mtb. In this study, we evaluated the frequency and phenotype of HLA-E restricted Mtb specific CD4+/CD8+ T cells in the circulation and bronchoalveolar lavage fluid of two independent non-human primate (NHP) studies and from humans receiving BCG either intradermally or mucosally. BCG vaccination followed by Mtb challenge in NHPs did not affect the frequency of circulating and local HLA-E/Mtb CD4+ and CD8+ T cells, and we saw the same in humans receiving BCG. HLA-E/Mtb T cell frequencies were significantly increased after Mtb challenge in unvaccinated NHPs, which was correlated with higher TB pathology. Together, HLA-E/Mtb restricted T cells are minimally induced by BCG in humans and rhesus macaques (RMs) but can be elicited after Mtb infection in unvaccinated RMs. These results give new insights into targeting HLA-E as a potential immune mechanism against TB.

Clinical use of nadofaragene firadenovec-vncg.

Non-muscle-invasive bladder cancer (NMIBC), which is restricted to the mucosa (stage Ta, carcinoma in situ (CIS)) or submucosa (stage T1), comprises 75% of bladder cancer diagnoses. Intravesical bacillus Calmette-Guérin (BCG) therapy is the standard-of-care initial treatment for high-risk NMIBC; however, a significant proportion of patients have BCG-unresponsive disease. While radical cystectomy is a definitive treatment in this setting, not all patients are willing or able to undergo this complex procedure associated with morbidity, mortality, and decreased quality of life. Bladder-preserving options for patients with BCG-unresponsive NMIBC represent an unmet need in this patient population. Nadofaragene firadenovec-vncg (Adstiladrin) is a nonreplicating adenoviral vector-based gene therapy indicated for the treatment of adult patients with high-risk BCG-unresponsive NMIBC with CIS with or without papillary tumors. The antitumor efficacy of nadofaragene firadenovec is driven by its local delivery of copies of the gene encoding for interferon alpha-2b (IFNα-2b) to urothelial cells. In the phase III CS-003 study, over half of participants with CIS exhibited a complete response by month 3 after instillation, with minimal serious adverse events. The favorable efficacy and safety profile, clinical utility, novel mechanism of action, and every 3-month dosing schedule give nadofaragene firadenovec a unique role in the treatment of high-risk BCG-unresponsive NMIBC. This review provides a practical approach to the effective clinical use of nadofaragene firadenovec regarding pre-instillation visit arrangements, storage, handling, instillation procedures, and post-instillation procedures. Implementation of these recommendations will ensure efficient real-world use of nadofaragene firadenovec and the development of useful training materials and relevant standard operating procedures to help support a clinic's treatment for patients with BCG-unresponsive NMIBC with CIS. Video Abstract https://vimeo.com/user17898099/review/953723559/e18af7ec43.

Real-word outcomes for high-risk non-muscle-invasive bladder cancer: screened patients for the BRAVO trial.

OBJECTIVE: To report real-world outcomes for high-risk non-muscle-invasive bladder cancer (HRNMIBC), including bacillus Calmette-Guérin (BCG) and radical cystectomy (RC), as randomised comparisons of these have not been possible. METHODS: We detail consecutive participants screened for the BRAVO randomised controlled trial comparing RC with BCG (International Standard Randomised Controlled Trial Number [ISRCTN]12509361). Patients were prospectively registered and case-note review used for outcomes. The primary outcome was overall survival. Secondary outcomes included recurrence, progression, metastasis, and bladder cancer-specific survival. RESULTS AND LIMITATIONS: A total of 193 patients were screened, including 106 (54.9%) who received BCG, 43 (22.3%) primary RC, 37 (19.2%) 'other' treatment and seven (3.6%) hyperthermic intravesical mitomycin C. All-cause death occurred in 55 (28.5%) patients at median (interquartile range [IQR]) of 29.0 (19.5-42.0) months. In multivariable analysis, overall mortality was more common in older patients (hazard ratio [HR] 2.63, 95% confidence interval [CI] 1.35-5.13; Cox P = 0.004 for age >70 years), those recruited from district hospitals (HR 0.53, 95% CI 0.3-0.95; P = 0.032) and those who did not undergo RC as their first treatment (HR 2.16, 95% CI 1.17-3.99; P = 0.014). In all, 17 (8.8%) patients died from bladder cancer (BC) at median (IQR) of 22.5 (19-36.25) months. In multivariable analysis, BC-specific mortality was more common in older patients (HR 4.87, 95% CI 1.1-21.6; P = 0.037) and those with Tis/T1 disease (HR 2.26, 95% CI 1.23-4.16; P = 0.008) but did not vary with initial treatment. CONCLUSIONS: Patients with HRNMIBC are at high-risk of mortality. Those choosing RC as their initial treatment have lower risks of mortality than others, although this may reflect fitness and selection.

Comparative study on the efficacy of low-dose and full-dose BCG bladder perfusion therapy.

BACKGROUND: Full-dose BCG bladder perfusion therapy is effective, but there are serious side effects. Whether a low dose of BCG can reduce the side effects of treatment while maintaining its efficacy is still inconclusive. OBJECTIVE: To compare the efficacy of low-dose and full-dose BCG bladder perfusion therapy and to provide reference for individual treatment of bladder cancer. METHODS: All relevant literature published in PubMed, Web of Science, and Embrase databases up to April 2024 was searched. The results and shortcomings of the existing literature are analyzed, the cognitive gaps between different studies are pointed out, and suggestions are made for future research. RESULTS: A total of 32 pieces of literature were included. Twelve studies found that the efficacy of full-dose BCG perfusion was significantly better than that of low-dose BCG perfusion, and 20 studies found no statistical difference between low-dose and full-dose BCG perfusion CONCLUSION: Although there is no significant difference in the efficacy of full-dose and low-dose BCG in bladder perfusion, the trend indicates that the efficacy of full-dose BCG is still the most accurate. In cases where BCG resources are scarce or patients are intolerant, low-dose BCG bladder perfusion therapy may be an alternative to full-dose BCG bladder perfusion therapy. High-quality, large-sample prospective cohort studies (or randomized controlled studies) are still needed in the future.

Insights into the multifaceted role of interleukin-37 on human immune cell regulation.

Autoinflammatory diseases, while having a variety of underlying causes, are mediated by dysfunctional innate immune responses. Therefore, standard treatments target innate cytokines or block their receptors. Despite excellent responses in some patients, first-line treatments fail in others, for reasons which remain to be understood. We studied the effects of IL-37, an anti-inflammatory cytokine, on immune cells using multi-omics profiling of 325 healthy adults. Our findings show that IL-37 is associated with inflammation control and generally reduced immune cell activity. Further, genetic variants in IL37 are associated with impaired trained immunity, a memory phenotype of innate immune cells contributing to autoinflammation. To underpin the medical potential of IL-37, an explorative cohort of seven autoinflammatory disorders was built. In vitro stimulation experiments argue for recombinant IL-37 as a potential therapy in IL-6-, and IL-22-driven conditions. Concluding, IL-37 is highlighted as a cytokine with broad anti-inflammatory functions, implicating its potential as therapeutic intervention.

BCG immunization induced KLRG1+ NK cells show memory-like responses to mycobacterial and HIV antigens.

Bacille-Calmette-Guérin (BCG) is the only approved vaccine against Mycobacterium tuberculosis (MTB), offering protection not only against tuberculosis (TB) but also non-related infections. 'Trained immunity' of innate immune cells is considered one of the mechanisms of this broad protection derived through BCG. Here, we investigated the effect of BCG on Natural Killer (NK) cells, a key innate immune cell type, and their subsequent responses to mycobacterial and HIV antigens. We found that BCG-induced KLRG1+ NK cells exhibit significantly higher production of IFNγ, compared to KLRG1- cells, indicating their memory-like responses upon exposure to these antigens (p < 0.05). These findings may be important in regions of high burden of HIV and TB where BCG is routinely administered.

Efficacy and tolerance of hyperthermic intravesical chemotherapy (HIVEC) according to the number of instillations administered.

PURPOSE: To report the oncological outcomes and the tolerance between 6 instillations and more than 6 cycles of hyperthermic intravesical chemotherapy(HIVEC) in patients with non-muscle invasive bladder cancer(NMIBC). METHODS: This is a multicenter retrospective study from a national database including 9 expert centers. All patients treated with HIVEC between 2016 and 2023 for NMIBC were included. Patients were classified into two groups according to the total number of HIVEC instillations, including induction plus maintenance. Kaplan-Meier curves were computed to present survival outcomes. RESULTS: 261 patients with a median follow-up of 25.5 months were included. 199(76.2%) and 62(23.8%) were treated by 6 and more than 6 cycles of HIVEC, respectively. The 2-years RFS(40.2% vs. 34.4%,p = 0.3) and the 2-years PFS(86% vs. 87%,p = 0.85) were similar between group treated with 6 and more than 6 instillations. 2-years CSS and OS were also similar between both groups. Univariate Cox regression showed no association between the number of bladder instillation and RFS (HR = 1.2 95%CI[0.8-1.84], p = 0.3) or PFS (HR = 0.8 95%CI[0.29-2.02], p = 0.2). In the group treated with more than 6 cycles, 2-years RFS and 2-years PFS were similar between patients who received induction plus maintenance compared to those treated with induction only. Finally, hematuria and urinary burning were significantly higher in the group treated by more than 6 cycles (21% vs. 8.5%(p < 0.01),and 29% vs. 17% (p = 0.03), respectively). Serious side effects(grade ≥ 3) are rare(3.1%) and similar in both groups. CONCLUSIONS: Results show no significant difference in two years RFS, PFS, CSS and OS according to number of instillations received, while toxicity profile seems better in the group receiving six instillations only.

Efficacy and outcomes of BCG re-vaccination in COVID-19: a systematic review, meta-analysis, and meta-regression of randomized controlled trials.

Introduction: The Bacillus Calmette-Guerin (BCG) vaccine has a beneficial "off-target" effect that offers heterologous protection against respiratory tract infections by inducing trained immunity. The need for producing antigen-specific COVID-19 vaccines leads to delays in vaccine administration. Current randomized controlled trials (RCTs) report conflicting data on BCG's efficacy in COVID-19 infection. Methods: A comprehensive literature search was conducted using major bibliographic databases to identify RCTs evaluating the outcomes of BCG re-vaccination in COVID-19. For dichotomous outcomes, odds ratios (ORs) with 95% CIs were pooled using the DerSimonian-Laird random-effects model. Statistical significance was set at P less than 0.05. Results: Thirteen RCTs with 13 939 participants (7004 in the BCG re-vaccination group and 6935 in the placebo group) were included. BCG re-vaccination did not lead to a statistically significant difference in the incidence of COVID-19 infection [OR: 1.04; 95% CI: 0.91, 1.19; P=0.56], COVID-19-related hospitalizations [OR: 0.81; 95% CI: 0.38, 1.72; P=0.58), ICU admissions [OR: 0.43; 95% CI: 0.13, 1.46; P=0.18], or mortality [OR: 0.67; 95% CI 0.15, 3.04; P=0.60]. For safety outcomes, BCG re-vaccination led to a significant increase in the local injection site complications [OR: 99.79; 95% CI: 31.04, 320.80; P<0.00001], however, the risk of serious adverse events was similar [OR: 1.19; 95% CI: 0.84, 1.67; P=0.33]. Conclusions: BCG re-vaccination does not decrease the incidence of COVID-19 infection, COVID-19-related hospitalizations, ICU admissions, COVID-19-related mortality, and serious adverse events; however, it leads to a rise in local injection site complications. Caution should be exercised when overstating BCG's efficacy in COVID-19 prevention.

Intranasal vaccination with engineered BCG expressing CCL2 induces a stronger immune barrier against Mycobacterium tuberculosis than BCG.

Intradermal Mycobacterium bovis Bacillus Calmette-Guérin (BCG) vaccination is currently the only licensed strategy for preventing tuberculosis (TB). It provides limited protection against pulmonary TB. To enhance the efficacy of BCG, we developed a recombinant BCG expressing exogenous monocyte chemoattractant CC chemokine ligand 2 (CCL2) called rBCG-CCL2. Co-culturing macrophages with rBCG-CCL2 enhances their abilities in migration, phagocytosis, and effector molecule expression. In the mouse model, intranasal vaccination with rBCG-CCL2 induced greater immune cell infiltration and a more extensive innate immune response in lung compared to vaccination with parental BCG, as determined by multiparameter flow cytometry, transcriptomic analysis, and pathological assessments. Moreover, rBCG-CCL2 induced a high frequency of activated macrophages and antigen-specific T helper 1 (Th1) and Th17 T cells in lungs. The enhanced immune microenvironment responded more effectively to intravenous challenge with Mycobacterium tuberculosis (Mtb) H37Ra, leading to significant reductions in H37Ra burden and pathological damage to the lungs and spleen. Intranasal rBCG-CCL2-vaccinated mice rapidly initiated pro-inflammatory Th1 cytokine release and reduced pathological damage to the lungs and spleen during the early stage of H37Ra challenge. The finding that co-expression of CCL2 synergistically enhances the immune barrier induced by BCG provides a model for defining immune correlates and mechanisms of vaccine-elicited protection against TB.

Tuberculosis and T cells: Impact of T cell diversity in tuberculosis infection.

Tuberculosis is a global threat and is still a leading cause of death due to an infectious agent. The infection is spread through inhalation of M. tb containing aerosol droplets. Bacteria after reaching the lung alveoli are engulfed by alveolar macrophages, leading to an immune response. Then, pro-inflammatory cytokines are released by these macrophages, recruiting other antigen-presenting cells like dendritic cells. These cells phagocytose the bacteria and present mycobacterial antigens to naïve T cells. After activation by DCs, T cells differentiate into various T cells subsets, viz. CD4+, CD8+, Th17, Treg, Tfh cells and others display enormous diversification in their characteristics and functions. This review comprises a comprehensive literature on conventional and unconventional T cells, highlighting the polyfunctional T cells as well, their role in controlling TB infection, and their implications in the spectrum of TB infection. While some subsets such as CD4+ T cells are extensively studied, some T cell subsets such as gamma delta T cells and Tfh cells remain poorly understood in the pathophysiology of tuberculosis, despite having significant potential implications. The goal of TB eradication can be assisted by development of better vaccines against TB, which can effectively induce a robust and long-term T cells memory. The same has been discussed in the latter part of this review. BCG being the standalone commercialised TB vaccine so far has its limitations. Strategies for the enhancement of BCG along with novel studies in vaccine development, has also been discussed in great detail. Lastly, T cells display a complex interplay of an adaptive immune response against TB, with activation and enhancement of the innate immune responses. Therefore, it is critical to fully understand the role of various T cells subsets in pathophysiology of tuberculosis to provide better therapeutic inventions and improve patient care.

Early transcriptomic response of innate immune cells to subcutaneous BCG vaccination of mice.

OBJECTIVES: Current data suggests that Bacille Calmette-Guerin (BCG) vaccination contributes to nonspecific enhancement of resistance to various infections. Thus, BCG vaccination induces both specific immunity against mycobacteria and non-specific "trained immunity" against various pathogens. To understand the fundamental mechanisms of "trained" immunity, studies of transcriptome changes occurring during BCG vaccination in innate immunity cells, as well as in their precursors, are necessary. Furthermore, this data possesses important significance for practical applications associated with the development of recombinant BCG strains aimed to enhance innate immunity against diverse infectious agents. DATA DESCRIPTION: We performed RNA sequencing of innate immune cells derived from murine bone marrow and spleen three days after subcutaneous BCG vaccination. Using fluorescence-activated cell sorting we obtained three cell populations for each mouse from both control and BCG vaccinated groups: bone marrow monocytes and neutrophils and splenic NK-cells. Then double-indexed cDNA libraries for Illumina sequencing from the collected samples were prepared, the resulting cDNA library mix was subjected to NovaSeq 6000 sequencing. This paper describes the collection of 24 RNA sequencing samples comprising 4 sets of immune cell populations obtained from subcutaneously BCG-vaccinated and control mice.

HLA-E and NKG2A Mediate Resistance to M. bovis BCG Immunotherapy in Non-Muscle-Invasive Bladder Cancer.

Mycobacterium bovis Bacillus Calmette-Guerin (BCG) is the primary treatment for non-muscle-invasive bladder cancer (NMIBC), known to stimulate inflammatory cytokines, notably interferon (IFN)-γ. We observed that prolonged IFN-γ exposure fosters adaptive resistance in recurrent tumors, aiding immune evasion and tumor proliferation. We identify HLA-E and NKG2A, part of a novel NK and T cell checkpoint pathway, as key mediators of resistance in BCG-unresponsive NMIBC. IFN-γ enhances HLA-E and PD-L1 expression in recurrent tumors, with an enrichment of intra-tumoral NKG2A-expressing NK and CD8 T cells. CXCL9+ macrophages and dendritic cells and CXCL12-expressing stromal cells likely recruit CXCR3/CXCR4-expressing NK and T cells and CXCR7+ HLA-EHIGH tumor cells. NK and CD8 T cells remain functional within BCG-unresponsive tumors but are inhibited by HLA-E and PD-L1, providing a framework for combined NKG2A and PD-L1 blockade strategy for bladder-sparing treatment of BCG-unresponsive NMIBC.

Immunoproteomic discovery of Mycobacterium bovis antigens, including the surface lipoprotein Mpt83 as a T cell antigen useful for vaccine development.

Tuberculosis (TB) is one of the leading causes of death from infectious diseases, killing approximately 1.3 million people worldwide in 2022 alone. The current vaccine for TB contains a live attenuated bacterium, Mycobacterium bovis BCG (Bacille Calmette-Guérin). The BCG vaccine is highly effective in preventing severe forms of childhood TB but does not protect against latent infection or disease in older age groups. A new or improved BCG vaccine for prevention of pulmonary TB is urgently needed. In this study, we infected murine bone marrow derived dendritic cells from C57BL/6 mice with M. bovis BCG followed by elution and identification of BCG-derived MHC class I and class II-bound peptides using tandem mass spectrometry. We identified 1436 MHC-bound peptides of which 94 were derived from BCG. Fifty-five peptides were derived from MHC class I molecules and 39 from class II molecules. We tested the 94 peptides for their immunogenicity using IFN- γ ELISPOT assay with splenocytes purified from BCG immunized mice and 10 showed positive responses. Seven peptides were derived from MHC II and three from MHC class I. In particular, MHC class II binding peptides derived from the mycobacterial surface lipoprotein Mpt83 were highly antigenic. Further evaluations of these immunogenic BCG peptides may identify proteins useful as new TB vaccine candidates.