Tuberculosis Vaccine Research Articles

The TB vaccine clinical trial centre directory: An inventory of clinical trial centres in Sub-Saharan Africa.

There are over ten vaccine candidates for tuberculosis (TB) in the clinical pipeline that require testing in TB-prevalent populations. To accelerate the clinical development of TB vaccines, a directory of clinical trial centres was established in sub-Saharan Africa (SSA) to assess capacity for conducting late-stage TB vaccine trials. TB vaccine-related parameters were identified, and trial centres in SSA were identified and prioritized based on whether they had experience with TB or non-TB vaccine trials. A survey was sent to identified centres, and the resulting directory presents their capacity for TB vaccine trials. Centres that identified as eligible for TB vaccine trials also had the opportunity to participate to the survey. This article provides an overview of the TB vaccine clinical trial centre directory, including the number and distribution of centres, their general characteristics, and their experience with prior TB vaccine trials. It includes information on the capacity of the centres, such as laboratory biosafety level, patient support, and community engagement. It also includes a case study to demonstrate how the directory can be used to identify trial centres with specific capabilities needed for a particular TB vaccine trial. Of the 134 identified centres, 56 provided information. Of these centres, 51 (91%) had phase 3 clinical trial experience and previous TB trials were conducted at 38 centres. Regarding TB vaccine trials, 19 centres conducted prevention of disease trials, 14 conducted prevention of infection trials, and 27 had no experience with TB vaccine clinical trials. From the respondents, 29 centers in South Africa were identified that could potentially conduct TB vaccine trials, followed by Tanzania (5), Kenya (5), Nigeria (3), and Uganda and Ethiopia (2 each). Trial sites in other countries were underrepresented, based on this survey. The establishment of a clinical trial centre directory can provide a basis for decision-making by various stakeholders. Despite some limitations in survey methodology, the findings suggest opportunities for expanding the evaluation of clinical trial capacity in other disease-prevalent countries and continents. Such data would be valuable in further enriching the Clinical Trial Community which a resource that geographically highlights clinical trial investments and capacities in African research ecosystem. New TB vaccine candidates need to be assessed in clinical trials in countries with high rates of TB in the coming years.An open-access directory of TB vaccine clinical trial centres in sub-Saharan Africa was established, providing an overview of the capacity to conduct clinical trials for TB vaccine candidates (http://www.edctp.org/our-work/coordination-tb-vaccine-funded-research/directory-tb-vaccine-clinical-trial-sites-sub-saharan-africa/).The directory is intended for clinical triallists, funders, policymakers, and researchers to accelerate the clinical development of novel TB vaccines by providing useful information.Regular updates are necessary to ensure the directory remains relevant for vaccine development and feeds into the continental Clinical Trials Community (https://ctc.africa/).

The potential impact of new TB vaccines on the burden of TB in people living with HIV in South Africa.

People living with HIV (PLHIV) are at increased risk of tuberculosis (TB). New TB vaccines may help reduce this burden. New TB vaccine candidates are safe and immunogenic in PLHIV.There is currently limited data on vaccine efficacy in this population. Using mathematical modelling we explored the potential impact of a novel TB vaccine on TB burden in PLHIV in South Africa between 2030-2050. We compared the impact of a vaccine delivered irrespective of HIV status to vaccination of either PLHIV or people without HIV. We explored the impact of reduced vaccine efficacy and duration of protection in PLHIV relative to people without HIV on our model predictions. Vaccination irrespective of HIV status, with a vaccine with equal efficacy and duration in PLHIV, could avert up to 1.01 (95% range: 0.96-1.22) million TB cases in PLHIV. Restricting vaccination to PLHIV or people without HIV would achieve 65% (60-70) and 48% (46-53) of the total impact respectively. These results are strongly dependent on the assumed efficacy and duration of protection in PLHIV. Further information on these characteristics is important to identify the most efficient use of new vaccines to reduce TB burden in PLHIV. Our results suggest that new vaccines could play an important role in reducing the TB burden in PLHIV. Vaccines targeted at people without HIV individuals could provide significant indirect benefit to PLHIV, but vaccines which are safe and effective in PLHIV will be critical to maximizing the impact in this population.

6684 Multi-Dose BCG Vaccination for Protection Against COVID-19 Disease and Other Respiratory Infections in Subjects with Type 1 Diabetes Late in the US Pandemic

Abstract Disclosure: W. Kühtreiber: None. E. Hostetter: None. G.E. Wolfe: None. M. Vaishnaw: None. R. Goldstein: None. E. Bulczynski: None. N. Hullavarad: None. J.E. Braley: None. H. Zheng: None. D.L. Faustman: None. A Phase II clinical trial previously reported that multiple doses of the bacillus Calmette-Guerin (BCG) vaccine, originally developed for tuberculosis prevention, could protect at-risk individuals with type 1 diabetes (T1D) against COVID-19 disease and infectious diseases early in the pandemic in the United States (US) (Cell Rep Med 2022). As SARS-CoV-2 evolved, COVID-19 disease became more transmissible, but less lethal. In a new, Phase III, randomized, double-blinded, placebo-controlled trial, we tested whether at-risk individuals with T1D given multi-dose, intradermal BCG would be protected against COVID-19 and other infectious diseases (2:1 randomization; BCG: n=93; placebo: n=48). The trial was conducted late in the COVID-19 pandemic during sequential dominance of Beta, Gamma, Delta and Omicron variants. All participants were US citizens and were negative for prior BCG vaccination and negative for tuberculosis. Two co-primary endpoints were protection from COVID-19 disease and platform protection from all infectious diseases. From April 2021 to November 2022, Tokyo-strain BCG vaccination provided significant protection against COVID-19 disease (p=0.023) and strong platform protection against all infectious diseases (p<0.0001). Over the 19-month course of the study, commercial COVID-19 vaccines were rolled out. An observational analysis of the placebo control group (i.e., no BCG vaccination) showed that COVID-19 mRNA vaccination alone provided no protection from COVID-19 disease in the enrolled population (p=0.43). BCG vaccination efficacy against COVID-19 and infectious disease in T1D was unaffected by concurrent COVID-19 vaccinations (observational analysis). These data suggest that BCG has efficacy against a range of SARS-CoV-2 variants, in contrast to current COVID-19 vaccines, which have narrow efficacy against specific viral variants. Further, it shows that individuals with T1D represent a vulnerable population for whom BCG appears to be the only effective vaccine against COVID-19 disease and confirms that, in the US, BCG vaccination protects against infectious disease as well. Presentation: 6/3/2024

Evaluation of PLGA, lipid-PLGA hybrid nanoparticles, and cationic pH-sensitive liposomes as tuberculosis vaccine delivery systems in a Mycobacterium tuberculosis challenge mouse model – A comparison

Tuberculosis (TB) continues to pose a global threat for millennia, currently affecting over 2 billion people and causing 10.6 million new cases and 1.3 million deaths annually. The only existing vaccine, Mycobacterium Bovis Bacillus Calmette-Guérin (BCG), provides highly variable and inadequate protection in adults and adolescents. This study explores newly developed subunit tuberculosis vaccines that use a multistage protein fusion antigen Ag85b-ESAT6-Rv2034 (AER). The protection efficacy, as well as in vivo induced immune responses, were compared for five vaccines: BCG; AER-CpG/MPLA mix; poly(D,L-lactic-co-glycolic acid) (PLGA); lipid-PLGA hybrid nanoparticles (NPs); and cationic pH-sensitive liposomes (the latter three delivering AER together with CpG and MPLA). All vaccines, except the AER-adjuvant mix, induced protection in Mycobacterium tuberculosis (Mtb)-challenged C57/Bl6 mice as indicated by a significant reduction in bacterial burden in lungs and spleens of the animals. Four AER-based vaccines significantly increased the number of circulating multifunctional CD4+ and CD8+ T-cells producing IL-2, IFNγ, and TNFα, exhibiting a central memory phenotype. Furthermore, AER-based vaccines induced an increase in CD69+ B-cell counts as well as high antigen-specific antibody titers. Unexpectedly, none of the observed immune responses were associated with the bacterial burden outcome, such that the mechanism responsible for the observed vaccine-induced protection of these vaccines remains unclear. These findings suggest the existence of non-classical protective mechanisms for Mtb infection, which could, once identified, provide interesting targets for novel vaccines.

Therapy modulates the response to T cell epitopes over the spectrum of tuberculosis infection

Identifying stage-specific antigens is essential for developing tuberculosis (TB) diagnostics and vaccines. In a low TB endemic country, we characterized, the Mycobacterium tuberculosis (Mtb)-specific immune response to a pool of Mtb-derived epitopes (ATB116), demonstrated as associated with TB disease. In this prospective observational cross-sectional study, we enrolled healthy donors (HD), subjects with TB disease, and TB infection (TBI) at baseline and therapy completion. T-cell response after whole blood stimulation with the peptide pools was characterized by ELISA, flow cytometry, and multiplex assay. ATB116-specific IFN-γ response (by ELISA) significantly associates with Mtb regardless of infection/disease (p<0.0001) and decreases during TB therapy (p=0.0002). Flow cytometry confirms that ATB116-specific CD4+ T-cell response associated with Mtb regardless of infection/disease (p<0.0001) and shows a significantly higher frequency of IFN-γ/IL-2 and central memory T-cells in TBI compared to TB (p=0.016; p=0.0242, respectively). CD4+ T cell-specific response decreases after TB therapy completion. The antigen-specific CD8+ T-cell response mirrors the CD4+ response. Finally, the multiplex assay analysis showed that ATB116 induces several immune factors in both TB and TBI. We characterized the immune response to Mtb peptide pools that is modulated by TB therapy. These results are important for our understanding of TB immunopathogenesis and vaccine design.

Intravenous Bacillus Calmette-Guérin (BCG) Induces a More Potent Airway and Lung Immune Response than Intradermal BCG in Simian Immunodeficiency Virus-infected Macaques.

Tuberculosis (TB), caused by Mycobacterium tuberculosis, is one of the leading causes of death due to an infectious agent. Coinfection with HIV exacerbates M. tuberculosis infection outcomes in people living with HIV. Bacillus Calmette-Guérin (BCG), the only approved TB vaccine, is effective in infants, but its efficacy in adolescents and adults is limited. In this study, we investigated the immune responses elicited by BCG administered via i.v. or intradermal (i.d.) routes in SIV-infected Mauritian cynomolgus macaques (MCM) without the confounding effects of M. tuberculosis challenge. We assessed the impact of vaccination on T cell responses in the airway, blood, and tissues (lung, thoracic lymph nodes, and spleen), as well as the expression of cytokines, cytotoxic effectors, and key transcription factors. Our results showed that i.v. BCG induces a robust and sustained immune response, including tissue-resident memory T cells in lungs, polyfunctional CD4+ and CD8αβ+ T cells expressing multiple cytokines, and CD8αβ+ T cells and NK cells expressing cytotoxic effectors in airways. We also detected higher levels of mycobacteria-specific IgG and IgM in the airways of i.v. BCG-vaccinated MCM. Although i.v. BCG vaccination resulted in an influx of tissue-resident memory T cells in lungs of MCM with controlled SIV replication, MCM with high plasma SIV RNA (>105 copies/ml) typically displayed reduced T cell responses, suggesting that uncontrolled SIV or HIV replication would have a detrimental effect on i.v. BCG-induced protection against M. tuberculosis.

Optimal control and cost-effectiveness analysis for a tuberculosis vaccination model with two latent classes

Optimal control and cost-effectiveness analysis for a tuberculosis vaccination model with two latent classes

Intranasal Immunization with a Recombinant Adenovirus Encoding Multi-Stage Antigens of Mycobacterium tuberculosis Preferentially Elicited CD8+ T Cell Immunity and Conferred a Superior Protection in the Lungs of Mice than Bacillus Calmette-Guerin.

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

The impact of pulmonary tuberculosis on SARS-CoV-2 infection: a nationwide cohort study.

The interaction between COVID-19 and tuberculosis (TB) is not yet fully understood, and large-scale research on the mortality outcome of such dual infection has been limited. This study aimed to investigate the impact of PTB on mortality among patients with COVID-19 within a Korean population by conducting an extensive analysis of a nationwide large dataset. We investigated the mortality and disease severity among COVID-19 patients who had PTB in South Korea. This study analyzed 462,444 out of 566,494 COVID-19 patients identified between January 2020 and December 2021. A total of 203 COVID-19 with PTB patients and 812 matched COVID-19 without PTB were analyzed using 1:4 propensity score matching. COVID-19 patients with PTB exhibited higher in-hospital mortality (odds ratio (OR) 3.02, 95% confidence interval (CI) 1.45-6.27, p-value = 0.003) and were at increased risk of requiring conventional oxygen therapy (OR 1.57, 95% CI 1.10-2.25, p-value = 0.013) as well as high flow nasal cannula (HFNC) or noninvasive ventilation (NIV) oxygen therapy (OR 1.91, 95 CI 1.10-3.32, p-value = 0.022) compared to those without PTB. Compared to matched COVID-19 without PTB, co-infected patients showed increased mortality rates across various timeframes, including during hospitalization, and at 30 day and 90 day intervals. In-hospital mortality rates were particularly elevated among women, individuals with malignancy, and those with lower incomes. Furthermore, the increased in-hospital mortality among PTB patients persisted irrespective of the timing of TB diagnosis or vaccination status against COVID-19. We suggest that physicians be aware of the risk of mortality and severity among COVID-19 patients with PTB; coinfection with COVID-19 is a critical situation that remains to be further explored and needs more attention in countries with an intermediate to high PTB burden.

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.

PreVenTB trial: protocol for evaluation of efficacy and safety of two vaccines VPM1002 and Immuvac (Mw) in preventing tuberculosis (TB) in healthy household contacts of newly diagnosed sputum smear-positive pulmonary TB patients: phase III, randomised, double-blind, three-arm placebo-controlled trial

IntroductionTuberculosis (TB) continues to be one of the deadliest infectious diseases over the centuries, killing more people worldwide than any other single infectious disease. There is an urgent need for...

“We’re Not Lab Rats”: Analysis of Netizens’ Response to BCG Vaccine-Test Proposal Against COVID-19 in Africa

In April 2020, two French scientists proposed Africa as the site for testing a BCG tuberculosis vaccine for treating COVID-19. This sparked social media outrage with some describing the gaffe as a hangover of colonial mentality. This study examined netizens’ interpretation of the faux pas and how the social media activism that followed it shaped the narrative about Africa’s identity. The study found that netizens interpreted the discourse as racism against Africa, colonialism, and a breach of medical ethics. These created an avenue for social media activism by a new generation of African netizens to assert their independence, protect their humanity, and promote the idea of Africa for Africans. The study recommends the need for ethics of care and racial sensitivity in public and global health discourses that have the potential to reopen scars of historical trauma in subjugated populations who may be geographically or socially affected by pandemics.

Correlation between systemic allergen desensitisation and long-term asthma protection in mice following intravenous administration of the live tuberculosis vaccine MTBVAC

MTBVAC is a live attenuated tuberculosis vaccine, currently undergoing phase III evaluation for tuberculosis prevention. In previous preclinical studies, we found that local pulmonary administration of MTBVAC via the intranasal route had a strong therapeutic effect against asthma. This effect correlated with the abrogation of allergen-specific Th2 response in the lungs. Using different mouse models of asthma, we investigated the effect of MTBVAC administered by intravenous (IV) route and its potential as immunotherapeutic agent to induce desensitisation of allergen-specific responses at a systemic level. We explored the effects of this process in the efficacy against airway hyperresponsiveness (AHR) induced by exposure to different allergens. IV MTBVAC was highly efficient at reducing AHR induced by different allergens. Additionally, IV MTBVAC was found to be well-tolerated, being progressively eliminated from the different organs analysed. From a mechanistic standpoint, we observed that MTBVAC intravenous, but not intranasal, impaired allergen-specific Th2 response in both lungs and spleen. This reduction at a systemic level correlated with long-term therapeutic protection against allergen exposure. Our results also revealed differential immunological mechanisms governing systemic and local pulmonary allergen desensitisation processes. Notably, in a cohort of patients with asthma sensitive to house dust mite (HDM), invitro incubation of peripheral blood mononuclear cells (PBMCs) with MTBVAC prevented allergen-specific production of Th2 cytokines IL-4 and IL-5. Altogether, our results suggest that intravenous MTBVAC could be a plausible allergen desensitising approach for treatment of asthma, and could provide long-term protection against allergen exposure. MCIN/AEI/10.13039/501100011033 [grants number RTI2018-097625-B-I00 and PID2022-138624OB-I00]; Consorcio Centro de Investigación Biomédica en Red- (Groups CB06/06/0020 and CB06/06/0013), Instituto de Salud Carlos III.

A noninvasive BCG skin challenge model for assessing tuberculosis vaccine efficacy.

We report here on the characterisation in mice of a noninvasive bacille Calmette-Guérin (BCG) skin challenge model for assessing tuberculosis (TB) vaccine efficacy. Controlled human infection models (CHIMs) are valuable tools for assessing the relevant biological activity of vaccine candidates, with the potential to accelerate TB vaccine development into the clinic. TB infection poses significant constraints on the design of a CHIM using the causative agent Mycobacterium tuberculosis (Mtb). A safer alternative is a challenge model using the attenuated vaccine agent Mycobacterium bovis BCG as a surrogate for Mtb, and intradermal (skin) challenge as an alternative to pulmonary infection. We have developed a unique noninvasive imaging system based on fluorescent reporters (FluorBCG) to quantitatively measure bacterial load over time, thereby determining a relevant biological vaccine effect. We assessed the utility of this model to measure the effectiveness of 2 TB vaccines: the currently licenced BCG and a novel subunit vaccine candidate. To assess the efficacy of the skin challenge model, a nonlinear mixed-effects models was built describing the decline of fluorescence over time. The model-based analysis identified that BCG vaccination reduced the fluorescence readout of both fluorophores compared to unvaccinated mice (p < 0.001). However, vaccination with the novel subunit candidate did not alter the fluorescence decline compared to unvaccinated mice (p > 0.05). BCG-vaccinated mice that showed the reduced fluorescent readout also had a reduced bacterial burden in the lungs when challenged with Mtb. This supports the fluorescence activity in the skin as a reflection of vaccine induced functional pulmonary immune responses. This novel noninvasive approach allows for repeated measurements from the challenge site, providing a dynamic readout of vaccine induced responses over time. This BCG skin challenge model represents an important contribution to the ongoing development of controlled challenge models for TB.

A study of antigen selection by extracellular vesicles as vaccine candidates against Mycobacterium tuberculosis infection.

Introduction. Tuberculosis (TB), an infectious disease caused by Mycobacterium tuberculosis (M. tb), remains a significant global public health concern. It is crucial to develop more effective vaccines for TB in order to achieve global control of the disease. Extracellular vesicles (EVs) are spherical membrane-bound structures released by pathogens and host cells. During the course of an infection, both pathogen- and host-derived EVs are produced and play important roles in determining the course of the infection. EVs offer intriguing tools as potential vaccines due to their ability to deliver multiple pathogen or host antigens.Hypothesis /Gap Statement. We hypothesized that EVs derived from M. tb and EVs from M. tb-infected macrophages may serve as potential vaccine candidates against M. tb infection.Aim. This study aims to compare the immunogenicity and immune protection between M. tb EVs and M. tb-infected macrophage-derived EVs.Methodology. In this study, EVs were extracted from culture supernatants of M. tb and M. tb-infected macrophages, respectively. Mass spectrometry was employed to explore the antigen composition of H37Rv-Mφ-EVs and H37Rv-EVs. Cytokine profiling and antibody response assays were used to analyse the immunogenicity offered by EVs. Additionally, we used histological examination to evaluate and protective efficacy of the EVs.Results. Our results demonstrated that mice immunized by EVs released from M. tb-infected macrophages induced stronger inflammatory cytokine response than M. tb. Moreover, EVs from M. tb-infected macrophages reinforced T-cell activation and antibody response compared to M. tb EVs. Proteomic analysis revealed that EVs from M. tb-infected macrophages containing immunodominant cargos have stronger binding ability with major histocompatibility complex molecules, which may contribute to the protection from M. tb infection. Indeed, immunization of EVs released from M. tb-infected macrophages significantly reduced the bacterial load and better protection against M. tb infection than EVs from M. tb. Importantly, the selected antigens (Ag85B, ESAT-6 and the Rv0580c) from EVs of M. tb-infected macrophages exhibited effective immunogenicity.Conclusion. Our results suggested that EVs derived from M. tb-infected macrophages might serve as a proper antigenic library for vaccine candidates against M. tb challenge.

Trends in Viral Vector-Based Vaccines for Tuberculosis: A Patent Review (2010-2023).

Tuberculosis (TB) is an ancient global public health problem. Several strategies have been applied to develop new and more effective vaccines against TB, from attenuated or inactivated mycobacteria to recombinant subunit or genetic vaccines, including viral vectors. This review aimed to evaluate patents filed between 2010 and 2023 for TB vaccine candidates. It focuses on viral vector-based strategies. A search was carried out in Espacenet, using the descriptors "mycobacterium and tuberculosis" and the classification A61K39. Of the 411 patents preliminarily identified, the majority were related to subunit vaccines, with 10 patents based on viral vector platforms selected in this study. Most of the identified patents belong to the United States or China, with a concentration of patent filings between 2013 and 2023. Adenoviruses were the most explored viral vectors, and the most common immunodominant Mycobacterium tuberculosis (Mtb) antigens were present in all the selected patents. The majority of patents were tested in mouse models by intranasal or subcutaneous route of immunization. In the coming years, an increased use of this platform for prophylactic and/or therapeutic approaches for TB and other diseases is expected. Along with this, expanding knowledge about the safety of this technology is essential to advance its use.

From pathogenesis to antigens: the key to shaping the future of TB vaccines.

Tuberculosis (TB) remains one of the gravest global health challenges. Mycobacterium tuberculosis (M. tuberculosis), the causative agent, employs sophisticated immune evasion and pathogenesis strategies. Its capability to thrive within immune cells and incite robust inflammatory responses prolongs infection and dissemination. Mycobacterial advanced adaptations facilitate navigation through the human immune system and present a variable antigenic profile throughout different infection stages. Investigating these strategies unfolds targeted approaches to effective vaccine development against TB. This review delves into the most advanced and exhaustive insights into the immune evasion tactics and pathogenic processes of M. tuberculosis across various infection stages. The knowledge distilled from this analysis holds the promise of guiding the creation of innovative TB vaccines and translating theoretical groundwork into practical immunological defenses.

Intravenous BCG induces a more potent airway and lung immune response than intradermal BCG in SIV-infected macaques.

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), is one of the leading causes of death due to an infectious agent. Coinfection with HIV exacerbates Mtb infection outcomes in people living with HIV (PLWH). Bacillus Calmette-Guérin (BCG), the only approved TB vaccine, is effective in infants, but its efficacy in adolescents and adults is limited. Here, we investigated the immune responses elicited by BCG administered via intravenous (IV) or intradermal (ID) routes in Simian Immunodeficiency Virus (SIV)-infected Mauritian cynomolgus macaques (MCM) without the confounding effects of Mtb challenge. We assessed the impact of vaccination on T cell responses in the airway, blood, and tissues (lung, thoracic lymph nodes, and spleen), as well as the expression of cytokines, cytotoxic molecules, and key transcription factors. Our results showed that IV BCG induces a robust and sustained immune response, including tissue-resident memory T (TRM) cells in lungs, polyfunctional CD4+ and CD8αβ+ T cells expressing multiple cytokines, and CD8αβ+ T cells and NK cells expressing cytotoxic effectors in airways. We also detected higher levels of mycobacteria-specific IgG and IgM in the airways of IV BCG-vaccinated MCM. Although IV BCG vaccination resulted in an influx of TRM cells in lungs of MCM with controlled SIV replication, MCM with high plasma SIV RNA (>105 copies/mL) typically displayed reduced T cell responses, suggesting that uncontrolled SIV or HIV replication would have a detrimental effect on IV BCG-induced protection against Mtb.

Boosting Immunogenicity of a Recombinant Mycobacterium smegmatis Strain via Zinc-Dependent Ribosomal Proteins.

Tuberculosis (TB) continues to be a major global health burden and kills over a million people annually. New immunization strategies are required for the development of an efficacious TB vaccine that can potentially induce sterilizing immunity. In this study, we first confirmed that a live vaccine strain of Mycobacterium smegmatis, previously designated as IKEPLUS, conferred a higher survival benefit than the Bacillus Calmette-Guerin (BCG) in a murine model of intravenous Mycobacterium tuberculosis (Mtb) infection. We have shown that there was a significant increase in the expression of the Rv0282 gene, which is encoded in the esx-3 locus, which played an important role in iron uptake when IKEPLUS was grown in both low zinc and iron-containing Sauton medium. We then confirmed using in vitro assays of biofilm formation that zinc plays a vital role in the growth and formation of M. smegmatis biofilms. IKEPLUS grown in low zinc media led to the better protection of mice after intravenous challenge with a very high dosage of Mtb. We also showed that various variants of IKEPLUS induced apoptotic cell-death of infected macrophages at a higher rate than wild-type M. smegmatis. We next attempted to determine if zinc containing ribosomal proteins such as rpmb2 could contribute to protective efficacy against Mtb infection. Since BCG has an established role in anti-mycobacterial efficacy, we boosted BCG vaccinated mice with rmpb2, but this did not lead to an increment in the protection mediated by BCG.

Mathematical analysis of a novel fractional order vaccination model for Tuberculosis incorporating susceptible class with underlying ailment

ABSTRACT Tuberculosis (TB) is a communicable, airborne infection caused by the bacillus Mycobacterium tuberculosis. Pulmonary tuberculosis (PTB) is the most common presentation, although infection can spread anywhere to cause extra-pulmonary tuberculosis (EPTB). In this paper, a novel fractional order mathematical model is designed for the transmission dynamics of tuberculosis. Uninfected vulnerable individuals are categorized into the following: susceptible with underline ailment and susceptible without underline ailment. The research seeks to qualitatively and quantitatively analyze the proposed model and suggests comprehensive intervention measures for the control of tuberculosis among individuals with underline ailment. Some of the major highlights from the numerical investigation points out that TB vaccination is key to reducing the spread of TB among individuals with underline ailment. Furthermore, efforts to step down the spread of TB through awareness campaigns could significantly reduce the burden of the disease among individuals with co-morbidity.