The ΔfbpAΔsapM candidate vaccine derived from Mycobacterium tuberculosis H37Rv is markedly immunogenic in macrophages and induces robust immunity to tuberculosis in mice.

Tuberculosis (TB) remains a significant global health challenge, with approximately 1.5 million deaths per year. The Bacillus Calmette-Guérin (BCG) vaccine against TB is used in infants but shows variable protection. Here, we introduce a novel approach using a double gene knockout mutant (DKO) from wild-type Mycobacterium tuberculosis (Mtb) targeting fbpA and sapM genes. DKO exhibited enhanced anti-TB gene expression in mouse antigen-presenting cells, activating autophagy and inflammasomes. This heightened immune response improved ex vivo antigen presentation to T cells. Subcutaneous vaccination with DKO led to increased protection against TB in wild-type C57Bl/6 mice, surpassing the protection observed in caspase 1/11-deficient C57Bl/6 mice and highlighting the critical role of inflammasomes in TB protection. The DKO vaccine also generated stronger and longer-lasting protection than the BCG vaccine in C57Bl/6 mice, expanding both CD62L-CCR7-CD44+/-CD127+ effector T cells and CD62L+CCR7+/-CD44+CD127+ central memory T cells. These immune responses correlated with a substantial ≥ 1.7-log10 reduction in Mtb lung burden. The DKO vaccine represents a promising new approach for TB immunization that mediates protection through autophagy and inflammasome pathways.

Ag85B with c-di-AMP as mucosal adjuvant showed immunotherapeutic effects on persistent Mycobacterium tuberculosis infection in mice.

Tuberculosis (TB), caused by Mycobacterium tuberculosis, remains the leading cause of mortality by a single infectious agent in the world. M. tuberculosis infection could also result in clinical chronic infection, known as latent TB infection (LTBI). Compared to the current limited treatment, several subunit vaccines showed immunotherapeutic effects and were included in clinical trials. In this study, a subunit vaccine of Ag85B with a novel mucosal adjuvant c-di-AMP (Ag85B:c-di-AMP) was delivered intranasally to a persistent M. tuberculosis H37Ra infection mouse model, which also presented the asymptomatic characteristics of LTBI. Compared with Ag85B immunization, Ag85B:c-di-AMP vaccination induced stronger humoral immune responses, significantly higher CD4+ T cells recruitment, enhanced Th1/Th2/Th17 profile response in the lung, decreased pathological lesions of the lung, and reduced M. tuberculosis load in mice. Taken together, Ag85B:c-di-AMP mucosal route immunization provided an immunotherapeutic effect on persistent M. tuberculosis H37Ra infection, and c-di-AMP, as a promising potential mucosal adjuvant, could be further used in therapeutic or prophylactic vaccine strategies for persistent M. tuberculosis infection as well as LTBI.

Host and pathogen genetic diversity shape vaccine-mediated protection to Mycobacterium tuberculosis.

To investigate how host and pathogen diversity govern immunity against Mycobacterium tuberculosis (Mtb), we performed a large-scale screen of vaccine-mediated protection against aerosol Mtb infection using three inbred mouse strains [C57BL/6 (B6), C3HeB/FeJ (C3H), Balb/c x 129/SvJ (C129F1)] and three Mtb strains (H37Rv, CDC1551, SA161) representing two lineages and distinct virulence properties. We compared three protective modalities, all of which involve inoculation with live mycobacteria: Bacillus Calmette-Guérin (BCG), the only approved TB vaccine, delivered either subcutaneously or intravenously, and concomitant Mtb infection (CoMtb), a model of pre-existing immunity in which a low-level Mtb infection is established in the cervical lymph node following intradermal inoculation. We examined lung bacterial burdens at early (Day 28) and late (Day 98) time points after aerosol Mtb challenge and histopathology at Day 98. We observed substantial heterogeneity in the reduction of bacterial load afforded by these modalities at Day 28 across the combinations and noted a strong positive correlation between bacterial burden in unvaccinated mice and the degree of protection afforded by vaccination. Although we observed variation in the degree of reduction in bacterial burdens across the nine mouse/bacterium strain combinations, virtually all protective modalities performed similarly for a given strain-strain combination. We also noted dramatic variation in histopathology changes driven by both host and bacterial genetic backgrounds. Vaccination improved pathology scores for all infections except CDC1551. However, the most dramatic impact of vaccination on lesion development occurred for the C3H-SA161 combination, where vaccination entirely abrogated the development of the large necrotic lesions that arise in unvaccinated mice. In conclusion, we find that substantial TB heterogeneity can be recapitulated by introducing variability in both host and bacterial genetics, resulting in changes in vaccine-mediated protection as measured both by bacterial burden as well as histopathology. These differences can be harnessed in future studies to identify immune correlates of vaccine efficacy.

Immunogenic profiling of Mycobacterium tuberculosis Rv1513 reveals its ability to switch on Th1 based immunity.

Tuberculosis (TB) is one of the infectious diseases caused by the pathogen Mycobacterium tuberculosis that continuously threatens the global human health. Bacillus Calmette-Guérin (BCG) vaccine is the only vaccine that has been used clinically to prevent tuberculosis in recent centuries, but its limitations in preventing latent infection and reactivation of tuberculosis do not provide full protection. In this study, we selected the membrane-associated antigen Rv1513 of Mycobacterium. In order to achieve stable expression and function of the target gene, the prokaryotic expression recombinant vector pET30b-Rv1513 was constructed and expressed and purified its protein. Detection of IFN- γ levels in the peripheral blood of TB patients stimulated by whole blood interferon release assay (WBIA) and multi-microsphere flow immunofluorescence luminescence (MFCIA) revealed that the induced production of cytokines, such as IFN-γ and IL-6, was significantly higher than that in the healthy group. Rv1513 combined with adjuvant DMT (adjuvant system liposomes containing dimethyldioctadecylammonium bromide (DDA), monophospholipid A (MPL), and trehalose-660-dibenzoic acid (TDB)) was used to detect serum specific antibodies, cytokine secretion from splenic suprasplenic cell supernatants, and multifunctional T-cell levels in splenocytes in immunised mice. The levels of IFN-γ, TNF-α, and IL-2 secreted by mouse splenocytes were found in the Rv1513+DMT group and the BCG+Rv1513+DMT group. The serum levels of IgG and its subclasses and the number of IFN-γ+T cells, TNF-α+T and IFN-γ+TNF-α+T cells in the induced CD4+/CD8+T cells in mice were significantly higher than those in the BCG group, and the highest levels were found in the BCG+Rv1513+DMT group. These findings suggest that Rv1513/DMT may serve as a potential subunit vaccine candidate that may be effective as a booster vaccine after the first BCG vaccination.

Immunoinformatics and structural aided approach to develop multi-epitope based subunit vaccine against Mycobacterium tuberculosis.

Tuberculosis is a highly contagious disease caused by Mycobacterium tuberculosis (Mtb), which is one of the prominent reasons for the death of millions worldwide. The bacterium has a substantially higher mortality rate than other bacterial diseases, and the rapid rise of drug-resistant strains only makes the situation more concerning. Currently, the only licensed vaccine BCG (Bacillus Calmette-Guérin) is ineffective in preventing adult pulmonary tuberculosis prophylaxis and latent tuberculosis re-activation. Therefore, there is a pressing need to find novel and safe vaccines that provide robust immune defense and have various applications. Vaccines that combine epitopes from multiple candidate proteins have been shown to boost immunity against Mtb infection. This study applies an immunoinformatic strategy to generate an adequate multi-epitope immunization against Mtb employing five antigenic proteins. Potential B-cell, cytotoxic T lymphocyte, and helper T lymphocyte epitopes were speculated from the intended proteins and coupled with 50 s ribosomal L7/L12 adjuvant, and the vaccine was constructed. The vaccine's physicochemical profile demonstrates antigenic, soluble, and non-allergic. In the meantime, docking, molecular dynamics simulations, and essential dynamics analysis revealed that the multi-epitope vaccine structure interacted strongly with Toll-like receptors (TLR2 and TLR3). MM-PBSA analysis was performed to ascertain the system's intermolecular binding free energies accurately. The immune simulation was applied to the vaccine to forecast its immunogenic profile. Finally, in silico cloning was used to validate the vaccine's efficacy. The immunoinformatics analysis suggests the multi-epitope vaccine could induce specific immune responses, making it a potential candidate against Mtb. However, validation through the in-vivo study of the developed vaccine is essential to assess its efficacy and immunogenicity profile, which will assure active protection against Mtb.

Selenium nanoparticles enhance mucosal immunity against Mycobacterium bovis infection.

Selenium nanoparticles (SeNPs) enhance the immune response as adjuvants, increasing the efficacy of viral vaccines, including those for COVID-19. However, the efficiency of mucosal SeNPs in boosting vaccine-induced protective immunity against tuberculosis remains unclear. Therefore, this study aims to investigate whether the combination of SeNPs with the AH antigen (Ag85A-HspX) can boost respiratory mucosal immunity and thereby enhance the protective effects against tuberculosis. We synthesized SeNPs and assessed their impact on the immune response and protection against Mycobacterium bovis (M. bovis) as a mucosal adjuvant in mice, administered intranasally at a dose of 20 µg. SeNPs outperformed polyinosinic-polycytidylic acid (Poly IC) in stimulating the maturation of bone marrow-derived dendritic cells (BMDCs), which enhanced antigen presentation. SeNPs significantly activated and proliferated tissue-resident memory T cells (TRMs) and effector CD4+ T cells in the lungs. The vaccines elicited specific antibody responses in the respiratory tract and stimulated systemic Th1 and Th17 immune responses. Immunization with AH and SeNPs led to higher levels of mucosal secretory IgA in bronchoalveolar lavage fluid (BALF) and secretory IL-17 in splenocytes. Moreover, SeNPs immunized mice showed reduced M. bovis infection loads and inflammatory lesions in the lungs post-challenge. Notably, immunization with AH and SeNPs significantly reduced bacterial load in the lungs, achieving the lowest levels compared to all other tested groups. This study calls for pre-clinical investigation of AHB-SeNPs as an anti-bovine tuberculosis vaccine and for exploring its human vaccine potential, which is anticipated to aid in the development of innovative vaccines or adjuvants.

Comparative analysis of genomic characteristics and immune response between Mycobacterium tuberculosis strains cultured continuously for 25 years and H37Rv.

Tuberculosis (TB) continues to pose a significant global health challenge, emphasizing the critical need for effective preventive measures. Although many studies have tried to develop new attenuated vaccines, there is no effective TB vaccine. In this study, we report a novel attenuated Mycobacterium tuberculosis (M. tb) strain, CHVAC-25, cultured continuously for 25 years in the laboratory. CHVAC-25 exhibited significantly reduced virulence compared to both the virulent H37Rv strain in C57BL/6J and severe combined immunodeficiency disease mice. The comparative genomic analysis identified 93 potential absent genomic segments and 65 single nucleotide polymorphic sites across 47 coding genes. Notably, the deletion mutation of ppsC (Rv2933) involved in phthiocerol dimycocerosate synthesis likely contributes to CHVAC-25 virulence attenuation. Furthermore, the comparative analysis of immune responses between H37Rv- and CHVAC-25-infected macrophages showed that CHVAC-25 triggered a robust upregulation of 173 genes, particularly cytokines crucial for combating M. tb infection. Additionally, the survival of CHVAC-25 was significantly reduced compared to H37Rv in macrophages. These findings reiterate the possibility of obtaining attenuated M. tb strains through prolonged laboratory cultivation, echoing the initial conception of H37Ra nearly a century ago. Additionally, the similarity of CHVAC-25 to genotypes associated with attenuated M. tb vaccine positions it as a promising candidate for TB vaccine development.

[Latest advances in the development of tuberculosis vaccines in global clinical trials: a review].

Tuberculosis (TB) remains one of the biggest infectious killers worldwide. Vaccine is the most satisfactory tool for prevention of TB; however, Bacillus Calmette-Guérin (BCG), the widely used vaccine in clinical for the prevention of TB, has limitations in protective effects. Development of novel TB vaccines is therefore of urgent need. Currently, there are 15 novel TB vaccine candidates in clinical trials, including live-attenuated vaccines, inactivated vaccines, subunit vaccines and viral-vectored vaccines, which open the door for the ultimate target of the End TB Strategy. This review summarizes the latest advances in the development of TB vaccines in global clinical trials, so as to provide insights into TB control.

Mycobacterium tuberculosis strain with deletions in menT3 and menT4 is attenuated and confers protection in mice and guinea pigs.

The genome of Mycobacterium tuberculosis encodes for a large repertoire of toxin-antitoxin systems. In the present study, MenT3 and MenT4 toxins belonging to MenAT subfamily of TA systems have been functionally characterized. We demonstrate that ectopic expression of these toxins inhibits bacterial growth and this is rescued upon co-expression of their cognate antitoxins. Here, we show that simultaneous deletion of menT3 and menT4 results in enhanced susceptibility of M. tuberculosis upon exposure to oxidative stress and attenuated growth in guinea pigs and mice. We observed reduced expression of transcripts encoding for proteins that are essential or required for intracellular growth in mid-log phase cultures of ΔmenT4ΔT3 compared to parental strain. Further, the transcript levels of proteins involved in efficient bacterial clearance were increased in lung tissues of ΔmenT4ΔT3 infected mice relative to parental strain infected mice. We show that immunization of mice and guinea pigs with ΔmenT4ΔT3 confers significant protection against M. tuberculosis infection. Remarkably, immunization of mice with ΔmenT4ΔT3 results in increased antigen-specific TH1 bias and activated memory T cell response. We conclude that MenT3 and MenT4 are important for M. tuberculosis pathogenicity and strains lacking menT3 and menT4 have the potential to be explored further as vaccine candidates.

Randomised, double-blind, controlled phase 1 trial of the candidate tuberculosis vaccine ChAdOx1-85A delivered by aerosol versus intramuscular route.

BACKGROUND: A BCG booster vaccination administered via the respiratory mucosa may establish protective immune responses at the primary site of Mycobacterium tuberculosis infection. The primary objective of this trial was to compare the safety and immunogenicity of inhaled versus intramuscular administered ChAdOx1-85A. METHODS: We conducted a single-centre, randomised, double-blind, controlled phase 1 study (Swiss National Clinical Trials Portal number SNCTP000002920). After a dose-escalation vaccination in nine BCG-vaccinated healthy adults, a dose of 1 × 1010 vp of ChAdOx1-85A was administered to twenty BCG-vaccinated adults that were randomly allocated (1:1) into two groups: aerosol ChAdOx1-85A with intramuscular saline placebo or intramuscular ChAdOx1-85A with aerosol saline placebo, using block randomisation. A control group of ten BCG-naïve adults received aerosol ChAdOx1-85A at the same dose. Primary outcomes were solicited and unsolicited adverse events (AEs) up to day 16 post-vaccination and Serious AEs (SAEs) up to 24 weeks; secondary outcomes were cell-mediated and humoral immune responses in blood and bronchoalveolar lavage (BAL) samples. FINDINGS: Both vaccination routes were well tolerated with no SAEs. Intramuscular ChAdOx1-85A was associated with more local AEs (mostly pain at the injection site) than aerosol ChAdOx1-85A. Systemic AEs occurred in all groups, mainly fatigue and headaches, without differences between groups. Respiratory AEs were not different between BCG-vaccinated groups. Aerosol ChAdOx1-85A vaccination induced Ag85A BAL and systemic cellular immune responses with compartmentalisation of the immune responses: aerosol ChAdOx1-85A induced stronger BAL cellular responses, particularly IFNγ/IL17+CD4+ T cells; intramuscular ChAdOx1-85A induced stronger systemic cellular and humoral responses. INTERPRETATION: Inhaled ChAdOx1-85A was well-tolerated and induced lung mucosal and systemic Ag85A-specific T-cell responses. These data support further evaluation of aerosol ChAdOx1-85A and other viral vectors as a BCG-booster vaccination strategy.

Immune Response to the Recombinant Apa Protein from Mycobacterium tuberculosis Expressed in Streptomyces lividans After Intranasal Administration in Mice. Induction of Protective Response to Tubercle Bacillus Aerosols Exposure.

Identifying and evaluating potential vaccine candidates has become one of the main objectives to combat tuberculosis. Among them, mannosylated Apa antigen from Mycobacterium tuberculosis and the non-mannosylated protein expressed in Escherichia coli, have been studied. Although both proteins can induce a protective response in mice, it has been considered that native protein can be dispensed. In this work, we study the protective response induced by Apa expressed in E. coli and in Streptomyces lividans. The latter, like native is secreted as a double band of 45/47 kDa, however, only its 47 kDa band is mannosylated. Both antigens and BCG were intranasal administrated in mice, and animals were then challenged by aerosol with M. tuberculosis H37Rv. The results showed that both, Apa from S. lividans and E. coli conferred statistically significantly protection to animals compared to controls. The cytokine immune response was studied by an immunoassay after animals' immunization, revealing that Apa from S. lividans induced a statistically significant proliferation of T cell, as well as the expression of IFN-γ, IL-1ß, IL-17 and IL-10. In contrast, non-proliferation was obtained with non-mannosylated protein, but induction of IL-12 and IL-17 was observed. Together, these results demonstrate that both proteins were able to modulate a specific immune response against M. tuberculosis, that could be driven by different mechanisms possibly associated with the presence or not of mannosylation. Furthermore, stimulation of cells from BCG-vaccinated animals with the proteins could be an important tool, to help define the use of a given subunit-vaccine after BCG vaccination.

Enhancing tuberculosis vaccine development: a deconvolution neural network approach for multi-epitope prediction.

Tuberculosis (TB) a disease caused by Mycobacterium tuberculosis (Mtb) poses a significant threat to human life, and current BCG vaccinations only provide sporadic protection, therefore there is a need for developing efficient vaccines. Numerous immunoinformatic methods have been utilized previously, here for the first time a deep learning framework based on Deconvolutional Neural Networks (DCNN) and Bidirectional Long Short-Term Memory (DCNN-BiLSTM) was used to predict Mtb Multiepitope vaccine (MtbMEV) subunits against six Mtb H37Rv proteins. The trained model was used to design MEV within a few minutes against TB better than other machine learning models with 99.5% accuracy. The MEV has good antigenicity, and physiochemical properties, and is thermostable, soluble, and hydrophilic. The vaccine's BLAST search ruled out the possibility of autoimmune reactions. The secondary structure analysis revealed 87% coil, 10% beta, and 2% alpha helix, while the tertiary structure was highly upgraded after refinement. Molecular docking with TLR3 and TLR4 receptors showed good binding, indicating high immune reactions. Immune response simulation confirmed the generation of innate and adaptive responses. In-silico cloning revealed the vaccine is highly expressed in E. coli. The results can be further experimentally verified using various analyses to establish a candidate vaccine for future clinical trials.

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.

Inhaled aerosol viral-vectored vaccines against tuberculosis.

Bacille Calmette-Guérin (BCG) remains the sole licensed vaccine against tuberculosis (TB), despite its variable efficacy in protecting against pulmonary TB. The development of effective TB vaccines faces significant challenges, marked by the absence of validated correlates of protection and predictive animal models. Strategic approaches to enhance TB vaccines and augment BCG efficacy include utilising prime-boost strategies with viral-vectored vaccines and exploring innovative delivery techniques, such as mucosal vaccine administration. Viral vectors offer numerous advantages, including the capacity to accommodate genes encoding extensive antigenic fragments and the induction of robust immune responses. Aerosol delivery aligns with the route of Mycobacterium tuberculosis infection and holds the potential to enhance protective mucosal immunity. Aerosolised viral-vectored vaccines overcome anti-vector immunity, facilitating repeated aerosol deliveries.

Cell-Mediated Immune Response Against Mycobacterium tuberculosis and Its Potential Therapeutic Impact.

Cell-mediated immune response is critical for Mycobacterium tuberculosis (M.tb) control. Understanding of pathophysiology and role played by different cell mediators is essential for vaccine development and better management of patients with M.tb. A complex array of cytokines and chemokines are involved in the immune response against M.tb; however, their relative contribution in protection remains to be further explored. The purpose of this review is to summarize the current understanding regarding the cytokine and chemokine profiles in M.tb infection in order to assist research in the field to pursue new direction in prevention and control. We have also summarized recent findings on vaccine trials that have been developed and or are under trials that are targeting these molecules.

HtpG-A Major Virulence Factor and a Promising Vaccine Antigen against Mycobacterium tuberculosis.

Tuberculosis (TB) is the leading global cause of death f rom an infectious bacterial agent. Therefore, limiting its epidemic spread is a pressing global health priority. The chaperone-like protein HtpG of M. tuberculosis (Mtb) is a large dimeric and multi-domain protein with a key role in Mtb pathogenesis and promising antigenic properties. This dual role, likely associated with the ability of Heat Shock proteins to act both intra- and extra-cellularly, makes HtpG highly exploitable both for drug and vaccine development. This review aims to gather the latest updates in HtpG structure and biological function, with HtpG operating in conjunction with a large number of chaperone molecules of Mtb. Altogether, these molecules help Mtb recovery after exposure to host-like stress by assisting the whole path of protein folding rescue, from the solubilisation of aggregated proteins to their refolding. Also, we highlight the role of structural biology in the development of safer and more effective subunit antigens. The larger availability of structural information on Mtb antigens and a better understanding of the host immune response to TB infection will aid the acceleration of TB vaccine development.

Vaccines to control tuberculosis in cattle.

The age-old cattle disease has resisted rigorous control, but the BCG vaccine may do better.

Rapamycin improves the long-term T-cell memory and protective efficacy of tuberculosis subunit vaccine.

The formation of long-lived T-cell memory is a critical goal of vaccines against intracellular pathogens like Mycobacterium tuberculosis (M. tuberculosis). In this study, to access the adjuvant effect of rapamycin on tuberculosis subunit vaccine, we treated mice with rapamycin during the course of vaccination and then monitored the vaccine-specific long-term memory T cell recall responses and protective ability against mycobacterial organisms. Compared with the mice that received vaccine alone, rapamycin treatment enhanced the vaccine induced long-term IFN-γ and IL-2 recall responses, promoted the development of TCM (central memory) like cells and improved the long-term proliferative ability of lymphocytes. Long-duration (total 53 days) of low-dose rapamycin (75 µg/kg/day) treatment generated stronger vaccine-specific memory T cell responses than short-duration treatment (total 25 days). Moreover, rapamycin improved the vaccine's long-term protective efficacy, which resulted in a better reduction of 0.89-log10 CFU of mycobacterial organisms in the lungs compared with control without rapamycin treatment. These findings suggest that rapamycin may be considered in designing TB subunit vaccine regimens or as potential adjuvant to enhance vaccine-induced T cell memory response and to prolong the longevity of vaccine's protective efficacy.

Advances in understanding immune homeostasis in latent tuberculosis infection.

Nearly one-fourth of the global population is infected by Mycobacterium tuberculosis (Mtb), and approximately 90%-95% remain asymptomatic as latent tuberculosis infection (LTBI), an estimated 5%-10% of those with latent infections will eventually progress to active tuberculosis (ATB). Although it is widely accepted that LTBI transitioning to ATB results from a disruption of host immune balance and a weakening of protective immune responses, the exact underlying immunological mechanisms that promote this conversion are not well characterized. Thus, it is difficult to accurately predict tuberculosis (TB) progression in advance, leaving the LTBI population as a significant threat to TB prevention and control. This article systematically explores three aspects related to the immunoregulatory mechanisms and translational research about LTBI: (1) the distinct immunocytological characteristics of LTBI and ATB, (2) LTBI diagnostic markers discovery related to host anti-TB immunity and metabolic pathways, and (3) vaccine development focus on LTBI. This article is categorized under: Infectious Diseases > Molecular and Cellular Physiology Infectious Diseases > Genetics/Genomics/Epigenetics Immune System Diseases > Genetics/Genomics/Epigenetics.