The double-sided effects of Mycobacterium Bovis bacillus Calmette-Guérin vaccine

Enhancing in situ cancer vaccines using delivery technologies

In situ cancer vaccination refers to any approach that exploits tumour antigens available at a tumour site to induce tumour-specific adaptive immune responses. These approaches hold great promise for the treatment of many solid tumours, with numerous candidate drugs under preclinical or clinical evaluation and several products already approved. However, there are challenges in the development of effective in situ cancer vaccines. For example, inadequate release of tumour antigens from tumour cells limits antigen uptake by immune cells; insufficient antigen processing by antigen-presenting cells restricts the generation of antigen-specific T cell responses; and the suppressive immune microenvironment of the tumour leads to exhaustion and death of effector cells. Rationally designed delivery technologies such as lipid nanoparticles, hydrogels, scaffolds and polymeric nanoparticles are uniquely suited to overcome these challenges through the targeted delivery of therapeutics to tumour cells, immune cells or the extracellular matrix. Here, we discuss delivery technologies that have the potential to reduce various clinical barriers for in situ cancer vaccines. We also provide our perspective on this emerging field that lies at the interface of cancer vaccine biology and delivery technologies.

Low-dose M.tb infection but not BCG or MTBVAC vaccination enhances heterologous antibody titres in non-human primates

Introduction

Mycobacteria are known to exert a range of heterologous effects on the immune system. The mycobacteria-based Freund's Complete Adjuvant is a potent non-specific stimulator of the immune response used in immunization protocols promoting antibody production, and Mycobacterium bovis Bacille Calmette Guérin (BCG) vaccination has been linked with decreased morbidity and mortality beyond the specific protection it provides against tuberculosis (TB) in some populations and age groups. The role of heterologous antibodies in this phenomenon, if any, remains unclear and under-studied.

Methods

We set out to evaluate antibody responses to a range of unrelated pathogens following infection with Mycobacterium tuberculosis (M.tb) and vaccination with BCG or a candidate TB vaccine, MTBVAC, in non-human primates.

Results

We demonstrate a significant increase in the titer of antibodies against SARS-CoV-2, cytomegalovirus, Epstein-Barr virus, tetanus toxoid, and respiratory syncytial virus antigens following low-dose aerosol infection with M.tb. The magnitude of some of these responses correlated with TB disease severity. However, vaccination with BCG administered by the intradermal, intravenous or aerosol routes, or intradermal delivery of MTBVAC, did not increase antibody responses against unrelated pathogens.

Discussion

Our findings suggest that it is unlikely that heterologous antibodies contribute to the non-specific effects of these vaccines. The apparent dysregulation of B cell responses associated with TB disease warrants further investigation, with potential implications for risk of B cell cancers and novel therapeutic strategies.

Demonstrating the utility of the ex vivo murine mycobacterial growth inhibition assay (MGIA) for high-throughput screening of tuberculosis vaccine candidates against multiple Mycobacterium tuberculosis complex strains

Human tuberculosis (TB) is caused by various members of the Mycobacterium tuberculosis (Mtb) complex. Differences in host response to infection have been reported, illustrative of a need to evaluate efficacy of novel vaccine candidates against multiple strains in preclinical studies. We previously showed that the murine lung and spleen direct mycobacterial growth inhibition assay (MGIA) can be used to assess control of ex vivo mycobacterial growth by host cells. The number of mice required for the assay is significantly lower than in vivo studies, facilitating testing of multiple strains and/or the incorporation of other cellular analyses. Here, we provide proof-of-concept that the murine MGIA can be applied to evaluate vaccine-induced protection against multiple Mtb clinical isolates. Using an ancient and modern strain of the Mtb complex, we demonstrate that ex vivo bacillus Calmette-Guérin (BCG)-mediated mycobacterial growth inhibition recapitulates protection observed in the lung and spleen following in vivo infection of mice. Further, we provide the first report of cellular and transcriptional correlates of BCG-induced growth inhibition in the lung MGIA. The ex vivo MGIA represents a promising platform to gain early insight into vaccine performance against a collection of Mtb strains and improve preclinical evaluation of TB vaccine candidates.

IL-23 receptor signaling licenses group 3-like innate lymphoid cells to restrict a live-attenuated oral Chlamydia vaccine in the gut

An IFNγ-susceptible mutant of Chlamydia muridarum is attenuated in pathogenicity in the genital tract and was recently licensed as an intracellular Oral vaccine vector or intrOv. Oral delivery of intrOv induces transmucosal protection in the genital tract, but intrOv itself is cleared from the gut (without shedding any infectious particles externally) by IFNγ from group 3-like innate lymphoid cells (ILC3s). We further characterized the intrOv interactions with ILC3s in the current study, since the interactions may impact both the safety and efficacy of intrOv as an oral Chlamydia vaccine. Intracolonic inoculation with intrOv induced IFNγ that in return inhibited intrOv. The intrOv-IFNγ interactions were dependent on RORγt, a signature transcriptional factor of ILC3s. Consistently, the transfer of oral intrOv-induced ILC3s from RORγt-GFP reporter mice to IFNγ-deficient mice rescued the inhibition of intrOv. Thus, IFNγ produced by intrOv-induced ILC3s is likely responsible for inhibiting intrOv, which is further supported by the observation that oral intrOv did induce significant levels of IFNγ-producing LC3s (IFNγ+ILC3s). Interestingly, IL-23 receptor knockout (IL-23R-/-) mice no longer inhibited intrOv, which was accompanied by reduced colonic IFNγ. Transfer of oral intrOv-induced ILC3s rescued the IL-23R-/- mice to inhibit intrOv, validating the dependence of ILC3s on IL-23R signaling for inhibiting intrOv. Clearly, intrOv induces intestinal IFNγ+ILC3s for its own inhibition in the gut, which is facilitated by IL-23R signaling. These findings have provided a mechanism for ensuring the safety of intrOv as an oral Chlamydia vaccine and a platform for investigating how oral intrOv induces transmucosal protection in the genital tract.

Preclinical screen for protection efficacy of chlamydial antigens that are immunogenic in humans

To search for subunit vaccine candidates, immunogenic chlamydial antigens identified in humans were evaluated for protection against both infection and pathology in a mouse genital tract infection model under three different immunization regimens. The intramuscular immunization regimen was first used to evaluate 106 chlamydial antigens, which revealed that two antigens significantly reduced while 11 increased genital chlamydial burden. The two infection-reducing antigens failed to prevent pathology and 23 additional antigens even exacerbated pathology. Thus, intranasal mucosal immunization was tested next since intranasal inoculation with live Chlamydia muridarum prevented both genital infection and pathology. Two of the 29 chlamydial antigens evaluated were found to prevent genital infection but not pathology and three exacerbate pathology. To further improve protection efficacy, a combinational regimen (intranasal priming + intramuscular boosting + a third intraperitoneal/subcutaneous boost) was tested. This regimen identified four infection-reducing antigens, but only one of them prevented pathology. Unfortunately, this protective antigen was not advanced further due to its amino acid sequence homology with several human molecules. Two pathology-exacerbating antigens were also found. Nevertheless, intranasal mucosal priming with viable C. muridarum in control groups consistently prevented both genital infection and pathology regardless of the subsequent boosters. Thus, screening 140 different chlamydial antigens with 21 repeated multiple times in 17 experiments failed to identify a subunit vaccine candidate but demonstrated the superiority of viable chlamydial organisms in inducing immunity against both genital infection and pathology, laying the foundation for developing a live-attenuated Chlamydia vaccine.

Mycobacterium bovis and its impact on human and animal tuberculosis

Mycobacterium bovis is a slow-growing (16–20 h generation time), Gram-positive and acid-fast bacterium member of the Mycobacterium tuberculosis complex pathogen group (MTBC). They are characterized by a complex, protective cell wall containing mycolic acids. The MTBCs are the causative agents of tuberculosis (TB). Following initial infection, subsequent pathological changes, and the progress of infection depend on the interplay between host defence mechanisms and mycobacterial virulence factors and the balance between the immunologic protective responses and the damaging inflammatory processes. Progression of the disease is characterized by the formation of typical caseous tuberculous granuloma (inflammatory mononuclear cell aggregates) because of the host's immune response to infection. The transmission and epidemiology of Mycobacterium bovis are complex and vary depending on the situation and ecosystem. In the UK, the spread of BTB in the UK cattle herd can occur by transmitting the disease from cattle to cattle and between badgers but also between badgers and cattle. The disease is thought to be primarily a respiratory disease with spread between individuals through mechanisms such as coughing or transfer of bacteria in respiratory secretions. It is also thought that environmental contamination may also lead to some transmission. The protective cell wall of the organism is believed to allow the organism to survive outside an animal host, which can then transfer to new hosts following subsequent environmental exposure. In some situations, ingestion of pathogens in food can lead to infection. The relative contribution of these routes and precise transmission mechanisms needs to be better understood.

Engineering a dual vaccine against COVID-19 and tuberculosis

The COVID-19 pandemic, caused by SARS-CoV-2 virus, has been one of the top public health threats across the world over the past three years. Mycobacterium bovis BCG is currently the only licensed vaccine for tuberculosis, one of the deadliest infectious diseases in the world, that is caused by Mycobacterium tuberculosis. In the past decades, recombinant M.bovis BCG has been studied as a novel vaccine vector for other infectious diseases in humans besides tuberculosis, such as viral infections. In the current study, we generated a recombinant M. bovis BCG strain AspikeRBD that expresses a fusion protein consisting of M. tb Ag85A protein and the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein using synthetic biology technique. Our results show that the recombinant M. bovis BCG strain successfully expressed this fusion protein. Interestingly, the recombinant M. bovis BCG strain AspikeRBD significantly induced SARS-CoV-2 spike-specific T cell activation and IgG production in mice when compared to the parental M.bovis BCG strain, and was more potent than the recombinant M.bovis BCG strain expressing SARS-CoV-2 spike RBD alone. As expected, the recombinant M. bovis BCG strain AspikeRBD activated an increased number of M. tb Ag85A-specific IFNγ-releasing T cells and enhanced IgG production in mice when compared to the parental M.bovis BCG strain or the BCG strain expressing SARS-CoV-2 spike RBD alone. Taken together, our results indicate a potential application of the recombinant M. bovis BCG strain AspikeRBD as a novel dual vaccine against SARS-CoV-2 and M. tb in humans.

Evaluation of the safety and immunological effects of Bacillus Calmette-Guérin in combination with checkpoint inhibitor therapy in a patient with neuroendocrine carcinoma: a case report

BACKGROUND

Immune checkpoint inhibitors have revolutionized therapy of advanced and metastatic cancers. However, a significant proportion of patients do not respond to immune checkpoint inhibitors or develop resistance. Therefore, novel therapies or combinations of therapies that may act synergistically are needed. It has been suggested that induction of trained immunity may increase the response to immune checkpoint inhibitor therapy, through reprogramming myeloid cells toward an antitumor phenotype. On the other hand, activation of the immune system also carries the risk of potentially sustaining tumorgenicity and increasing immune- related toxicity.

CASE PRESENTATION

We report the case of a 37-year-old Dutch male suffering from gastric neuroendocrine carcinoma with liver metastases and high risk for an unfavorable outcome, who was treated with a combination of programmed cell death protein 1 inhibitor nivolumab and the trained immunity-inducer Bacillus Calmette-Guérin vaccine as a salvage therapy. Three doses of BCG vaccine were administered at 3-month intervals, in conjunction with the immune checkpoint inhibitor regimen. At a certain point, radiation therapy was added to the treatment regimen. During the combination of these therapies, the patient developed immune-mediated colitis, which necessitated discontinuation of all treatments. Bacillus Calmette-Guérin vaccination induced a trained immune response with elevated monocyte-derived interleukin-6 and interleukin-1β production capacity. From the first vaccination with Bacillus Calmette-Guérin until 3 months after the last vaccination with Bacillus Calmette-Guérin, the patient displayed only mild progression of the primary tumor and no progression of the metastases.

CONCLUSION

In this study, we show the feasibility to combine checkpoint inhibitor therapy with inducers of trained immunity in a patient with an aggressive neuroendocrine tumor. Autoimmune side effects are common under programmed cell death protein 1 inhibitor therapy, which was considered the most likely cause of colitis, although an additive effect of Bacillus Calmette-Guérin vaccination or radiotherapy cannot be excluded. The patient displayed only mild progression during the combination therapy, but larger studies are warranted to fully explore the potential benefit of trained immunity inducers as an adjuvant to immune checkpoint inhibitor therapy.

Disseminated Bacillus Calmette-Guérin infection: role of imaging in the evaluation of complications

BACKGROUND

The Bacillus Calmette-Guerin (BCG) vaccine is generally used to prevent tuberculosis, particularly meningeal and miliary types, in childhood. This vaccine can rarely cause complications of varying severity, ranging from localized disease to a severe diffuse type known as disseminated BCG infection. Imaging modalities play an important role in the evaluation of different complications of disseminated BCG infection. This study aimed to assess and describe the imaging findings of disseminated BCG infection in order to help clinicians diagnose this life-threatening infection more accurately.

METHODS

This retrospective study was performed on 44 hospitalized children diagnosed with disseminated BCG infection. The results of radiographs, sonography, computerized tomography (CT) scan and magnetic resonance imaging were compiled in a checklist and were then assessed by a radiology resident and a board-certificated radiologist. The radiological findings from various imaging modalities were presented descriptively and the frequency of different parameters was reported.

RESULTS

Axillary lymphadenopathy at the vaccinated side was frequent and was often associated with abscesses. However, abscesses in other body regions were uncommon. The most common abdominal imaging findings were enlarged liver and spleen accompanied by multiple hypoechoic and hypodense nodules on ultrasound and CT scans, respectively. Furthermore, diffuse or multifocal pulmonary opacities were the most frequent findings on chest X-rays and CT scans.

CONCLUSION

Characteristic imaging findings of disseminated BCG infection play a vital role in the early diagnosis of this infection. The study findings demonstrated the importance of radiological imaging in the diagnosis and evaluation of the complications of disseminated BCG infection.

Protection against tuberculosis achieved by dissolving microneedle patches loaded with live Mycobacterium paragordonae in a BCG prime-boost strategy

Introduction

Skin vaccination using dissolving microneedle patch (MNP) technology for transdermal delivery is a promising vaccine delivery strategy to overcome the limitations of the existing vaccine administration strategies using syringes. To improve the traditional microneedle mold fabrication technique, we introduced droplet extension (DEN) to reduce drug loss. Tuberculosis remains a major public health problem worldwide, and BCG revaccination had failed to increase the protective efficacy against tuberculosis. We developed an MNP with live Mycobacterium paragordonae (Mpg) (Mpg-MNP) as a candidate of tuberculosis booster vaccine in a heterologous prime-boost strategy to increase the BCG vaccine efficacy.

Materials and methods

The MNPs were fabricated by the DEN method on a polyvinyl alcohol mask film and hydrocolloid-adhesive sheet with microneedles composed of a mixture of mycobacteria and hyaluronic acid. We assessed the transdermal delivery efficiency by comparing the activation of the dermal immune system with that of subcutaneous injection. A BCG prime Mpg-MNP boost regimen was administered to a mouse model to evaluate the protective efficacy against M. tuberculosis.

Results

We demonstrated the successful transdermal delivery achieved by Mpg-MNP compared with that observed with BCG-MNP or subcutaneous vaccination via an increased abundance of MHCII-expressing Langerin+ cells within the dermis that could migrate into draining lymph nodes to induce T-cell activation. In a BCG prime-boost regimen, Mpg-MNP was more protective than BCG-only immunization or BCG-MNP boost, resulting in a lower bacterial burden in the lungs of mice infected with virulent M. tuberculosis. Mpg-MNP-boosted mice showed higher serum levels of IgG than BCG-MNP-boosted mice. Furthermore, Ag85B-specific T-cells were activated after BCG priming and Mpg-MNP boost, indicating increased production of Th1-related cytokines in response to M. tuberculosis challenge, which is correlated with enhanced protective efficacy.

Discussion

The MNP fabricated by the DEN method maintained the viability of Mpg and achieved effective release in the dermis. Our data demonstrate a potential application of Mpg-MNP as a booster vaccine to enhance the efficacy of BCG vaccination against M. tuberculosis. This study produced the first MNP loaded with nontuberculous mycobacteria (NTM) to be used as a heterologous booster vaccine with verified protective efficacy against M. tuberculosis.

Multidimensional futuristic approaches to address the pandemics beyond COVID-19

Globally, the impact of the coronavirus disease 2019 (COVID-19) pandemic has been enormous and unrelenting with ∼6.9 million deaths and ∼765 million infections. This review mainly focuses on the recent advances and potentially novel molecular tools for viral diagnostics and therapeutics with far-reaching implications in managing the future pandemics. In addition to briefly highlighting the existing and recent methods of viral diagnostics, we propose a couple of potentially novel non-PCR-based methods for rapid, cost-effective, and single-step detection of nucleic acids of viruses using RNA mimics of green fluorescent protein (GFP) and nuclease-based approaches. We also highlight key innovations in miniaturized Lab-on-Chip (LoC) devices, which in combination with cyber-physical systems, could serve as ideal futuristic platforms for viral diagnosis and disease management. We also discuss underexplored and underutilized antiviral strategies, including ribozyme-mediated RNA-cleaving tools for targeting viral RNA, and recent advances in plant-based platforms for rapid, low-cost, and large-scale production and oral delivery of antiviral agents/vaccines. Lastly, we propose repurposing of the existing vaccines for newer applications with a major emphasis on Bacillus Calmette-Guérin (BCG)-based vaccine engineering.

Comparative transcriptomes reveal pro-survival and cytotoxic programs of mucosal-associated invariant T cells upon Bacillus Calmette-Guérin stimulation

Mucosal-associated invariant T (MAIT) cells are protective against tuberculous and non-tuberculous mycobacterial infections with poorly understood mechanisms. Despite an innate-like nature, MAIT cell responses remain heterogeneous in bacterial infections. To comprehensively characterize MAIT activation programs responding to different bacteria, we stimulated MAIT cells with E. coli to compare with Bacillus Calmette-Guérin (BCG), which remains the only licensed vaccine and a feasible tool for investigating anti-mycobacterial immunity in humans. Upon sequencing mRNA from the activated and inactivated CD8+ MAIT cells, results demonstrated the altered MAIT cell gene profiles by each bacterium with upregulated expression of activation markers, transcription factors, cytokines, and cytolytic mediators crucial in anti-mycobacterial responses. Compared with E. coli, BCG altered more MAIT cell genes to enhance cell survival and cytolysis. Flow cytometry analyses similarly displayed a more upregulated protein expression of B-cell lymphoma 2 and T-box transcription factor Eomesodermin in BCG compared to E.coli stimulations. Thus, the transcriptomic program and protein expression of MAIT cells together displayed enhanced pro-survival and cytotoxic programs in response to BCG stimulation, supporting BCG induces cell-mediated effector responses of MAIT cells to fight mycobacterial infections.

Over 90% Percent of Childhood BCG Vaccine-Induced Keloids in Japan Occur in Women

INTRODUCTION

Keloids are a fibroproliferative, multifactorial, cutaneous disorder whose pathophysiology is not completely understood. Various factors such as high blood pressure, pregnancy, female gender, mechanical tension of local sites, and prolonged wound healing are known to worsen keloids. Childhood-onset keloids are keloids that form before 10 years of age, before various factors in adulthood come into play, and thus studying childhood-onset keloids may provide additional insight into the underlying mechanisms that lead to keloid formation.

METHODS

Retrospective chart review was performed on all patients with childhood-onset keloids who were evaluated at our plastic surgery clinic (one of the largest keloid referral centers in Japan) over a 1-year period.

RESULTS

Of the 1443 patients with diagnosis of keloids, 131 patients had childhood-onset keloids. Of these, 106 patients (80.9%) were female, 38.9% of patients had family history of keloids, and 48.9% of patients had allergies or allergy-related conditions (asthma, atopic dermatitis, or allergic rhinitis). Vaccination (47.5%) and chickenpox (19.9%) were the most common triggers. Of vaccinations, BCG was the most common trigger. The majority of keloids from BCG were in female patients (92.9%). The most common location was the chest in male patients (30.0%) and the arm in female patients (41.1%).

CONCLUSION

To our knowledge, this is the largest report in the literature on childhood-onset keloids. There was overall female predominance in childhood-onset keloids, and even more significant female predominance in BCG-induced keloids.

Efficacy of BCG Vaccination against COVID-19: Systematic Review and Meta-Analysis of Randomized Controlled Trials

Beneficial off-target effects of the Bacillus Calmette-Guérin (BCG) vaccination might offer general protection from respiratory tract infections. We conducted a systematic review and meta-analysis of published randomized controlled trials (RCTs) to ascertain BCG vaccination effectiveness against COVID-19. We looked up English RCTs from 1 January 2019 to 15 November 2022 in Embase, the Cochrane Library, and the Web of Science in this systematic review and meta-analysis. Nine RCTs, including 7963 participants, were included. The infection rate of COVID-19 was not decreased in people who were vaccinated with BCG (OR, 0.96; 95% CI, 0.82-1.13; I² = 4%), and the BCG vaccination group did not have decreased COVID-19 related-hospitalization (OR, 0.66; 95% CI, 0.37-1.18; I² = 42%), admission to the ICU (OR, 0.25; 95% CI, 0.05-1.18; I² = 0%), and mortality (OR, 0.64; 95% CI, 0.17-2.44; I² = 0%) compared with the control group. There is not sufficient evidence to support the use of BCG vaccination in the prevention of COVID-19 infection and severe COVID-19 and avoid overstating the role of BCG vaccination leading to its misuse.

Mycobacterium tuberculosis Infection among 1,659 Silicosis Patients in Zhejiang Province, China

Silicosis is a well-established risk factor for Mycobacterium tuberculosis infection. This study aimed to estimate the burden and risk factors of M. tuberculosis infection. Silicosis patients from Zhejiang Province were screened for M. tuberculosis by sputum culture, chest radiographs, whole-blood gamma interferon (IFN-γ) release assay (QuantiFERON-TB Gold In-Tube [QFT-GIT]), and tuberculin skin test (TST). Potential risk factors for M. tuberculosis were identified. Data for 1,659 patients were obtained from 1,684 participants. Of these, 1,656 (99.8%) were men, and the average age was 58 (54 to 63) years. The prevalence of active tuberculosis (ATB) was 6,340/100,000 (6.34%) people; the proportion of patients with latent tuberculosis infection (LTBI) was 50.6%. Age (odds ratio [OR] = 1.059, 95% confidence interval [CI] = 1.020 to 1.099, P = 0.003), being underweight (OR = 2.320, 95% CI = 1.057 to 5.089, P = 0.036), and having a history of exposure to TB patients (OR = 4.329, 95% CI = 1.992 to 9.434, P < 0.001) were associated with ATB; BCG vaccination could reduce ATB risk in silicosis patients (OR = 0.541, 95% CI = 0.307 to 0.954, P = 0.034). Among patients without ATB, the QFT-GIT positivity rate was 40.5%, which was affected by silicosis severity, while that of TST was 57.2%. BCG vaccination was an independent factor for LTBI risk reduction (OR = 0.612, 95% CI = 0.468 to 0.801, P < 0.001). The quantitative results of QFT-GIT decreased with silicosis stage (H = 6.037; P = 0.048). In conclusion, M. tuberculosis prevalence was high in silicosis patients. BCG vaccination reduced the risk of both ATB and LTBI in silicosis patients. IMPORTANCE This study evaluated the prevalence of Mycobacterium tuberculosis infection in silicosis patients in mainland China and identified the potential risk factors for both active tuberculosis (ATB) and latent tuberculosis infection (LTBI). We believe that our study makes a significant contribution to the literature because we demonstrated that M. tuberculosis prevalence was high among silicosis patients. BCG vaccination was an independent factor that reduced the risk of M. tuberculosis infection in patients with silicosis. Furthermore, we show that the prevalence of LTBI in patients with silicosis may have been underestimated by immunological detection methods. This study can help to identify targeted subgroups prioritized for M. tuberculosis control and to reduce the risk of disease development.

Morphology of Lymphoid Tissue in the Lungs of Guinea Pigs Infected with Mycobacterium bovis against the Background of Vaccine Immunity and the Action of Betulin and Its Derivatives

Tuberculosis caused by Mycobacterium bovis is a serious problem for animal and human health worldwide. A promising concept for the design of anti-tuberculosis drugs is the conjugation of an immunogenic fraction isolated from bacterial vaccines with a stimulating component. Taking this principle as a basis, conjugates based on BCG antigens with betulin and its derivatives (betulonic and betulinic acids) were designed. The aim of this research was to study the morphological changes in the lymphoid tissue associated with the bronchial mucosa lungs (BALT) in guinea pigs sensitized with experimental conjugates using a model of experimental tuberculosis. The results showed a significant decrease in the BALT response, expressed by a decrease in the diameter of lymphatic follicles and a decrease in their activity when exposed to conjugates based on BCG antigens with betulin and, especially, with betulonic acid, with a visually greater number of plasma cells observed in the lung tissues of guinea pigs of these groups. The absence of tuberculous foci and low BALT activity in the lungs of animals treated with betulin and betulonic acid are probably associated with the activation of humoral immunity under the action of these conjugates.

Vaccine Preventable Zoonotic Diseases: Challenges and Opportunities for Public Health Progress

Zoonotic diseases represent a heavy global burden, causing important economic losses, impacting animal health and production, and costing millions of human lives. The vaccination of animals and humans to prevent inter-species zoonotic disease transmission is an important intervention. However, efforts to develop and implement vaccine interventions to reduce zoonotic disease impacts are often limited to the veterinary and agricultural sectors and do not reflect the shared burden of disease. Multisectoral collaboration, including co-development opportunities for human and animal vaccines, expanding vaccine use to include animal reservoirs such as wildlife, and strategically using vaccines to interrupt complex transmission cycles is needed. Addressing zoonoses requires a multi-faceted One Health approach, wherein vaccinating people and animals plays a critical role.

CFP10-loaded PLGA nanoparticles as a booster vaccine confer protective immunity against Mycobacterium bovis

Introduction: The limited efficacy of BCG (bacillus Calmette-Guérin) urgently requires new effective vaccination approaches for the control of tuberculosis. Poly lactic-co-glycolic acid (PLGA) is a prevalent drug delivery system. However, the effect of PLGA-based nanoparticles (NPs) against tuberculosis for the induction of mucosal immune response is no fully elucidated. In this study, we hypothesized that intranasal immunization with culture filtrate protein-10 (CFP10)-loaded PLGA NPs (CFP10-NPs) could boost the protective immunity of BCG against Mycobacterium bovis in mice. Methods: The recombinant protein CFP10 was encapsulated with PLGA NPs to prepare CFP10-NPs by the classical water-oil-water solvent-evaporation method. Then, the immunoregulatory effects of CFP10-NPs on macrophages in vitro and on BCG-immunized mice in vivo were investigated. Results: We used spherical CFP10-NPs with a negatively charged surface (zeta-potential -28.5 ± 1.7 mV) having a particle size of 281.7 ± 28.5 nm in diameter. Notably, CFP10-NPs significantly enhanced the secretion of tumor necrosis factor α (TNF-α) and interleukin (IL)-1β in J774A.1 macrophages. Moreover, mucosal immunization with CFP10-NPs significantly increased TNF-α and IL-1β production in serum, and immunoglobulin A (IgA) secretion in bronchoalveolar lavage fluid (BALF), and promoted the secretion of CFP10-specific interferon-γ (IFN-γ) in splenocytes of mice. Furthermore, CFP10-NPs immunization significantly reduced the inflammatory area and bacterial load in lung tissues at 3-week post-M. bovis challenge. Conclusion: CFP10-NPs markedly improve the immunogenicity and protective efficacy of BCG. Our findings explore the potential of the airway mucosal vaccine based on PLGA NPs as a vehicle for targeted lung delivery.

Nanocages engineered from Bacillus Calmette-Guerin facilitate protective Vγ2Vδ2 T cell immunity against Mycobacterium tuberculosis infection

Tuberculosis (TB), induced by Mycobacterium tuberculosis (Mtb) infection, remains a top killer among infectious diseases. While Bacillus Calmette-Guerin (BCG) is the sole TB vaccine, the clumped-clustered features of BCG in intradermal immunization appear to limit both the BCG protection efficacy and the BCG vaccination safety. We hypothesize that engineering of clumped-clustered BCG into nanoscale particles would improve safety and also facilitate the antigen-presenting-cell (APC)’s uptake and the following processing/presentation for better anti-TB protective immunity. Here, we engineered BCG protoplasts into nanoscale membraned BCG particles, termed as “BCG-Nanocage” to enhance the anti-TB vaccination efficiency and safety. BCG-Nanocage could readily be ingested/taken by APC macrophages selectively; BCG-Nanocage-ingested macrophages exhibited better viability and developed similar antimicrobial responses with BCG-infected macrophages. BCG-Nanocage, like live BCG bacilli, exhibited the robust capability to activate and expand innate-like T effector cell populations of Vγ2+ T, CD4+ T and CD8+ T cells of rhesus macaques in the ex vivo PBMC culture. BCG-Nanocage immunization of rhesus macaques elicited similar or stronger memory-like immune responses of Vγ2Vδ2 T cells, as well as Vγ2Vδ2 T and CD4+/CD8+ T effectors compared to live BCG vaccination. BCG-Nanocage- immunized macaques developed rapidly-sustained pulmonary responses of Vγ2Vδ2 T cells upon Mtb challenge. Furthermore, BCG- and BCG-Nanocage- immunized macaques, but not saline controls, exhibited undetectable Mtb infection loads or TB lesions in the Mtb-challenged lung lobe and hilar lymph node at endpoint after challenge. Thus, the current study well justifies a large pre-clinical investigation to assess BCG-Nanocage for safe and efficacious anti-TB vaccination, which is expected to further develop novel vaccines or adjuvants.

Novel molecules as the emerging trends in cancer treatment: an update

As per World Health Organization cancer remains as a leading killer disease causing nearly 10 million deaths in 2020. Since the burden of cancer increases worldwide, warranting an urgent search for anti-cancer compounds from natural sources. Secondary metabolites from plants, marine organisms exhibit a novel chemical and structural diversity holding a great promise as therapeutics in cancer treatment. These natural metabolites target only the cancer cells and the normal healthy cells are left unharmed. In the emerging trends of cancer treatment, the natural bioactive compounds have long become a part of cancer chemotherapy. In this review, we have tried to compile about eight bioactive compounds from plant origin viz. combretastatin, ginsenoside, lycopene, quercetin, resveratrol, silymarin, sulforaphane and withaferin A, four marine-derived compounds viz. bryostatins, dolastatins, eribulin, plitidepsin and three microorganisms viz. Clostridium, Mycobacterium bovis and Streptococcus pyogenes with their well-established anticancer potential, mechanism of action and clinical establishments are presented.

Human Newborn Monocytes Demonstrate Distinct BCG-Induced Primary and Trained Innate Cytokine Production and Metabolic Activation In Vitro

Background

Newborns exhibit distinct immune responses and are at high risk of infection. Neonatal immunization with BCG, the live attenuated vaccine against tuberculosis (TB), is associated with broad protection against a range of unrelated pathogens, possibly reflecting vaccine-induced training of innate immune cells ("innate memory"). However, little is known regarding the impact of age on BCG-induced innate responses.

Objective

Establish an age-specific human monocyte in vitro training platform to characterize and compare BCG-induced primary and memory cytokine responses and immunometabolic shifts.

Design/Methods

Human neonatal and adult CD33-selected monocytes were stimulated for 24h with RPMI (control) or BCG (Danish strain) in 10% autologous serum, washed and cultured for 5 additional days, prior to re-stimulation with the TLR4 agonist LPS for another 24h. Supernatants were collected at Day 1 (D1) to measure primary innate responses and at Day 7 (D7) to assess memory innate responses by ELISA and multiplex cytokine and chemokine assays. Lactate, a signature metabolite increased during trained immunity, was measured by colorimetric assay.

Results

Cytokine production by human monocytes differed significantly by age at D1 (primary, BCG 1:750 and 1:100 vol/vol, p<0.0001) and D7 (innate memory response, BCG 1:100 vol/vol, p<0.05). Compared to RPMI control, newborn monocytes demonstrated greater TNF (1:100, 1:10 vol/vol, p<0.01) and IL-12p40 (1:100 vol/vol, p<0.05) production than adult monocytes (1:100, p<0.05). At D7, while BCG-trained adult monocytes, as previously reported, demonstrated enhanced LPS-induced TNF production, BCG-trained newborn monocytes demonstrated tolerization, as evidenced by significantly diminished subsequent LPS-induced TNF (RPMI vs. BCG 1:10, p <0.01), IL-10 and CCL5 production (p<0.05). With the exception of IL-1RA production by newborn monocytes, BCG-induced monocyte production of D1 cytokines/chemokines was inversely correlated with D7 LPS-induced TNF in both age groups (p<0.0001). Compared to BCG-trained adult monocytes, newborn monocytes demonstrated markedly impaired BCG-induced production of lactate, a metabolite implicated in immune training in adults.

Conclusions

BCG-induced human monocyte primary- and memory-innate cytokine responses were age-dependent and accompanied by distinct immunometabolic shifts that impact both glycolysis and training. Our results suggest that immune ontogeny may shape innate responses to live attenuated vaccines, suggesting age-specific approaches to leverage innate training for broad protection against infection.