IL-23 and IL-17 in tuberculosis. Cytokine. 2008;41:79-83. [PMID: 18218322 DOI: 10.1016/j.cyto.2007.11.022]

Effect of IL-17A on the immune response to pulmonary tuberculosis induced by high- and low-virulence strains of Mycobacterium bovis

Tuberculosis (TB) is an infectious, chronic, and progressive disease occurring globally. Human TB is caused mainly by Mycobacterium tuberculosis (M. tuberculosis), while the main causative agent of bovine TB is Mycobacterium bovis (M. bovis). The latter is one of the most important cattle pathogens and is considered the main cause of zoonotic TB worldwide. The mechanisms responsible for tissue damage (necrosis) during post-primary TB remain elusive. Recently, IL-17A was reported to be important for protection against M. tuberculosis infection, but it is also related to the production of an intense inflammatory response associated with necrosis. We used two M. bovis isolates with different levels of virulence and high IL-17A production to study this important cytokine's contrasting functions in a BALB/c mouse model of pulmonary TB. In the first part of the study, the gene expression kinetics and cellular sources of IL-17A were determined by real time PCR and immunohistochemistry respectively. Non-infected lungs showed low production of IL-17A, particularly by the bronchial epithelium, while lungs infected with the low-virulence 534 strain showed high IL-17A expression on Day 3 post-infection, followed by a decrease in expression in the early stage of the infection and another increase during late infection, on Day 60, when very low bacillary burdens were found. In contrast, infection with the highly virulent strain 04-303 induced a peak of IL-17A expression on Day 14 of infection, 1 week before extensive pulmonary necrosis was seen, being lymphocytes and macrophages the most important sources. In the second part of the study, the contribution of IL-17A to immune protection and pulmonary necrosis was evaluated by suppressing IL-17A via the administration of specific blocking antibodies. Infection with M. bovis strain 534 and treatment with IL-17A neutralizing antibodies did not affect mouse survival but produced a significant increase in bacillary load and a non-significant decrease in inflammatory infiltrate and granuloma area. In contrast, mice infected with the highly virulent 04-303 strain and treated with IL-17A blocking antibodies showed a significant decrease in survival, an increase in bacillary loads on Day 24 post-infection, and significantly more and earlier necrosis. Our results suggest that high expression of IL-17A is more related to protection than necrosis in a mouse model of pulmonary TB induced by M. bovis strains.

Bergenin potentiates BCG efficacy by enriching mycobacteria-specific adaptive memory responses via the Akt-Foxo-Stat4 axis

The extensive inability of the BCG vaccine to produce long-term immune protection has not only accelerated the disease burden but also progressed towards the onset of drug resistance. In our previous study, we have reported the promising effects of Bergenin (Berg) in imparting significant protection as an adjunct immunomodulator against tuberculosis (TB). In congruence with our investigations, we delineated the impact of Berg on T cells, wherein it enhanced adaptive memory responses by modulating key transcription factors, STAT4 and Akt. We translated this finding into the vaccine model of TB and observed a notable reduction in the burden of Mycobacterium tuberculosis (M.tb) in BCG-Berg co-immunized mice as compared to BCG vaccination. Moreover, Berg, along with BCG, also aided in a heightened proinflammatory response milieu that corroborates the host protective immune response against TB. Furthermore, this response aligns with the escalated central and resident memory responses by modulating the Akt-Foxo-Stat4 axis, which plays a crucial role in enhancing the vaccine efficacy of BCG. These findings showcase the utilization of immunomodulator Berg as an immunoprophylactic agent to upgrade immunological memory, making it a more effective defender against TB.

Biapenem, a Carbapenem Antibiotic, Elicits Mycobacteria Specific Immune Responses and Reduces the Recurrence of Tuberculosis

Tuberculosis (TB) still tops the list of global health burdens even after COVID-19. However, it will sooner transcend the current pandemic due to the prevailing risk of reactivation of latent TB in immunocompromised individuals. The indiscriminate misuse and overuse of antibiotics have resulted in the emergence of deadly drug-resistant variants of Mycobacterium tuberculosis (M.tb). This study aims to characterize the functionality of the carbapenem antibiotic-Biapenem (BPM) in generating long-lasting immunity against TB. BPM treatment significantly boosted the activation status of the innate immune arm-macrophages by augmenting p38 signaling. Macrophages further primed and activated the adaptive immune cells CD4+ and CD8+ T-cells in the lung and spleen of the infected mice model. Furthermore, BPM treatment significantly amplified the polarization of T lymphocytes toward inflammatory subsets, such as Th1 and Th17. The treatment also helped generate a long-lived central memory T-cell subset. The generation of central memory T lymphocyte subset upon BPM treatment in the murine model led to a significant curtailing in the recurrence of TB due to reactivation and reinfection. These results suggest the potentiality of BPM as a potent adjunct immunomodulator to improve host defense against M.tb by enriching long-term protective memory cells. IMPORTANCE Tuberculosis (TB) caused by Mycobacterium tuberculosis (M.tb) tops the list of infectious killers around the globe. The emergence of drug-resistant variants of M.tb has been a major hindrance toward realizing the "END TB" goal. Drug resistance has amplified the global burden toward the quest for novel drug molecules targeting M.tb. Host-directed therapy (HDT) offers a lucrative alternative to tackle emerging drug resistance and disease relapse by strengthening the host's immunity. Through our present study, we have tried to characterize the functionality of the carbapenem antibiotic-Biapenem (BPM). BPM treatment significantly augmented long-lasting immunity against TB by boosting the innate and adaptive immune arms. The generation of long-lived central memory T lymphocyte subset significantly improved the disease outcome and provided sterilizing immunity in the murine model of TB. The present investigation's encouraging results have helped us depict BPM as a potent adjunct immunomodulator for treating TB.

Latent Tuberculosis in Psoriasis Patients on Biologic Therapies: Real-World Data from a Care Center in Romania

Background and Objectives: Psoriasis is a chronic and inflammatory condition that has a huge impact on the patient's quality of life. Biological treatment improved psoriasis therapy, with impressive results seen in the evolution of the disease and the patient's quality of life. However, the risk of mycobacterium tuberculosis (MTB) infection reactivation is well-known to biological therapy, which raises problems especially in an endemic country. Materials and Methods: In this study, we followed moderate to severe psoriasis patients who had latent tuberculosis infection (LTBI) following treatment with a biological therapy approved in Romania. Results: The patients were evaluated at baseline and then followed-up with Mantoux tests and chest X-rays every year, resulting in 54 patients being diagnosed with LTBI. At the initial evaluation, 30 patients with LTBI were identified, and 24 more were identified during biological therapy. These patients were given prophylactic treatment. Out of the 97 participants in this retrospective study, 25 required association of methotrexate (MTX) alongside biological therapy. We compared the prevalence of positive Mantoux tests in patients with combined therapy with that of patients only on biological treatment, and the results were higher in the combined therapy group. Conclusion: All the patients in the study were vaccinated against tuberculosis (TB) after birth, and none were diagnosed with active tuberculosis (aTB) before or after the start of therapy according to the pulmonologist.

Systemic Levels of Pro-Inflammatory Cytokines and Post-Treatment Modulation in Tuberculous Lymphadenitis

Pro-inflammatory cytokines are potent stimulators of inflammation and immunity and markers of infection severity and bacteriological burden in pulmonary tuberculosis (PTB). Interferons could have both host-protective and detrimental effects on tuberculosis disease. However, their role has not been studied in tuberculous lymphadenitis (TBL). Thus, we evaluated the systemic pro-inflammatory (interleukin (IL)-12, IL-23, interferon (IFN)α, and IFNβ) cytokine levels in TBL, latent tuberculosis (LTBI), and healthy control (HC) individuals. In addition, we also measured the baseline (BL) and post-treatment (PT) systemic levels in TBL individuals. We demonstrate that TBL individuals are characterized by increased pro-inflammatory (IL-12, IL-23, IFNα, IFNβ) cytokines when compared to LTBI and HC individuals. We also show that after anti-tuberculosis treatment (ATT) completion, the systemic levels of pro-inflammatory cytokines were significantly modulated in TBL individuals. A receiver operating characteristic (ROC) analysis revealed IL-23, IFNα, and IFNβ significantly discriminated TBL disease from LTBI and/or HC individuals. Hence, our study demonstrates the altered systemic levels of pro-inflammatory cytokines and their reversal after ATT, suggesting that they are markers of disease pathogenesis/severity and altered immune regulation in TBL disease.

Preventive effects of Mycobacterium tuberculosis DNA vaccines on the mouse model with latent tuberculosis infection

Background

About a quarter of the world's population with latent tuberculosis infection (LTBI) are the main source of active tuberculosis. Bacillus Calmette Guerin (BCG) cannot effectively control LTBI individuals from developing diseases. Latency-related antigens can induce T lymphocytes of LTBI individuals to produce higher IFN-γ levels than tuberculosis patients and normal subjects. Herein, we firstly compared the effects of M. tuberculosis (MTB) ag85ab and 7 latent DNA vaccines on clearing latent MTB and preventing its activation in the mouse LTBI model.

Methods

A mouse LTBI model was established, and then immunized respectively with PBS, pVAX1 vector, Vaccae vaccine, ag85ab DNA and 7 kinds of latent DNAs (including rv1733c, rv2660c, rv1813c, rv2029c, rv2628, rv2659c and rv3407) for three times. The mice with LTBI were injected with hydroprednisone to activate the latent MTB. Then, the mice were sacrificed for the bacterial count, histopathological examination, and immunological evaluation.

Results

Using chemotherapy made the MTB latent in the infected mice, and then using hormone treatment reactivated the latent MTB, indicating that the mouse LTBI model was successfully established. After the mouse LTBI model was immunized with the vaccines, the lung colony-forming units (CFUs) and lesion degree of mice in all vaccines group were significantly decreased than those in the PBS group and vector group (P<0.0001, P<0.05). These vaccines could induce antigen-specific cellular immune responses. The number of IFN-γ effector T cells spots secreted by spleen lymphocytes in the ag85ab DNA group was significantly increased than those in the control groups (P<0.05). In the splenocyte culture supernatant, IFN-γ and IL-2 levels in the ag85ab, rv2029c, and rv2659c DNA groups significantly increased (P<0.05), and IL-17A levels in ag85ab and rv2659c DNA groups also significantly increased (P<0.05). Compared with the PBS and vector groups, the proportion of CD4⁺CD25⁺FOXP3⁺ regulatory T cells in spleen lymphocytes of ag85ab, rv2660c, rv2029c, and rv3407 DNA groups were significantly reduced (P<0.05).

Conclusions

MTB ag85ab and 7 kinds of latent DNA vaccines showed immune preventive efficacies on a mouse model of LTBI, especially the rv2659c, and rv1733c DNA. Our findings will provide candidates for the development of new multi-stage vaccines against TB.

Acinetobacter baumannii reinforces the pathogenesis by promoting IL-17 production in a mouse pneumonia model

Interleukin-17 (IL-17) is involved in host defense against bacterial infection. Little is known about the role of IL-17 in A. baumannii-infected pneumonia. Our objective was to investigate the role of IL-17 in pulmonary A. baumannii infection in a mouse model. We infected C57BL/6 mice intra-tracheally (i.t.) with A. baumannii to establish pneumonia model and found A. baumannii infection elevated IL-17 expression in lungs. IL-17-deficient (Il17^-/-) mice were resistant to pulmonary A. baumannii infection, showing improved mice survival, reduced bacteria burdens, and alleviated lung inflammation. Further, treatment of A. baumannii-infected Il17^-/- mice with IL-17 exacerbated the severity of pneumonia. These data suggest a pathogenic role of IL-17 in pulmonary A. baumannii infection. Further, the infiltration and phagocytic function of neutrophils in broncho-alveolar lavage fluid were detected by flow cytometry. The results showed that Il17^-/- mice had increased neutrophil infiltration and enhanced phagocytosis in neutrophils at the early time of infection. Treatment of mice with IL-17 suppressed phagocytic function of neutrophils. All data suggest that IL-17 promotes susceptibility of mice to pulmonary A. baumannii infection by suppressing neutrophil phagocytosis at early time of infection. Targeting IL-17 might be a potential therapeutic strategy in controlling the outcome of A. baumannii pneumonia.

Toxicity signals associated with secukinumab: A pharmacovigilance study based on the United States Food and Drug Administration Adverse Event Reporting System database

AIMS

Secukinumab, the first interleukin 17A inhibitor, is widely used to treat immune diseases, including plaque psoriasis, psoriatic arthritis and ankylosing spondylitis. Recently, many studies have reported adverse events associated with secukinumab, including gastrointestinal disorders, infections and infestations, and hypersensitive and nervous system disorders.

OBJECTIVE

Here, we aimed to explore the clinical characteristics, outcomes and time to onset of the four main toxicities of secukinumab using post-marketing data.

METHODS

Our study utilized data from the United States Food and Drug Administration Adverse Event Reporting System (FAERS) database from 2015 to 2021, using disproportionality analysis. Toxicities were defined based on the standardized Medical Dictionary for Regulatory Activities queries. Two disproportionality methods were used to detect potential signals: information component (IC) and reporting odds ratio (ROR). The signals were defined as ROR₀₂₅  > 1 and IC₀₂₅  > 0.

RESULTS

A total of 73 945 398 records were included in this study, of which 300 665 records were related to secukinumab. Diarrhoea (N = 3538), nasopharyngitis (N = 3458), pruritus (N = 4277) and rash (N = 3270) were the most common adverse events. Inflammatory bowel disease (IC₀₂₅ /ROR₀₂₅  = 3.25/9.69), genital candidiasis (IC₀₂₅ /ROR₀₂₅  = 3.46/11.54), dermatitis psoriasiform (IC₀₂₅ /RO_R025  = 1.94/4.04) and anosmia (IC₀₂₅ /ROR₀₂₅  = 1.62/3.17) had the highest IC₀₂₅ values of all toxicities. The time to onset of the four toxicities was mainly concentrated in the first month. Some patients simultaneously presented with two or more toxicities.

CONCLUSION

This pharmacovigilance study systematically explored the four main toxicities of secukinumab and provided new safety signals based on past safety information. Some high-risk signals need to be given attention.

Impact of diabetes mellitus on immunity to latent tuberculosis infection

Tuberculosis (TB) is an infectious disease that poses a major health threat and is one of the leading causes of death worldwide. Following exposure to Mycobacterium tuberculosis (M.tb) bacilli, hosts who fail to clear M.tb end up in a state of latent tuberculosis infection (LTBI), in which the bacteria are contained but not eliminated. Type 2 diabetes mellitus (DM) is a noncommunicable disease that can weaken host immunity and lead to increased susceptibility to various infectious diseases. Despite numerous studies on the relationship between DM and active TB, data on the association between DM and LTBI remains limited. Immunological data suggest that LTBI in the presence of DM leads to an impaired production of protective cytokines and poly-functional T cell responses, accounting for a potential immunological mechanism that could leads to an increased risk of active TB. This review highlights the salient features of the immunological underpinnings influencing the interaction between TB and DM in humans.

Phenotype and function of peripheral blood γδ T cells in HIV infection with tuberculosis

Background

Although γδ T cells play an essential role in immunity against Human Immunodeficiency Virus (HIV) or Mycobacterium tuberculosis (MTB), they are poorly described in HIV infection with tuberculosis (TB).

Methods

The phenotypic and functional properties of peripheral blood γδ T cells in patients with HIV/TB co-infection were analyzed compared to healthy controls and patients with HIV mono-infection or TB by direct intracellular cytokine staining (ICS).

Results

The percentage of Vδ₁ subset in HIV/TB group was significantly higher than that in TB group, while the decreased frequency of the Vδ₂ and Vγ₂Vδ₂ subsets were observed in HIV/TB group than in TB group. The percentage of CD4⁺CD8^- Vδ₂ subset in HIV/TB group was markedly lower than in TB group. However, the percentage of CD4⁺CD8⁺ Vδ₂ subset in HIV/TB group was markedly higher than HIV group or TB group. A lower percentage TNF-α and a higher percentage of IL-17A of Vδ₂ subset were observed in HIV/TB group than that in HIV mono-infection. The percentage of perforin-producing Vδ₂ subset was significantly lower in HIV/TB group than that in HIV group and TB group.

Conclusions

Our data suggested that HIV/TB co-infection altered the balance of γδ T cell subsets. The influence of HIV/TB co-infection on the function of γδ T cells to produce cytokines was complicated, which will shed light on further investigations on the mechanisms of the immune response against HIV and/or MTB infection.

Risk of Reactivation of Latent Tuberculosis in Psoriasis Patients on Biologic Therapies: A Retrospective Cohort from a Tertiary Care Centre in Northern Italy

Psoriatic patients with latent tuberculosis infection and properly treated active tuberculosis need careful management when prescribing modern biological drugs. Although data and guidelines regarding tumour necrosis factor-α inhibitors advise caution and initiation of prophylactic therapy in patients with latent tuberculosis infection, the same indications do not seem to find equal force for interleukin (IL)-23 and IL-17 inhibitors. In order to evaluate the risk of reactivation in patients with latent tuberculosis infection or properly treated active tuberculosis, an observational retrospective study was conducted on the population referred to our centre at Dermatologic Clinic of University of Turin, Italy. In the last 10 years at the clinic 19 psoriatic patients were found to be at risk of tuberculosis reactivation: 10 patients were QuantiFERON- TB-positive at baseline, 2 became positive during treatment, 6 reported prior tuberculous infection, and 1 was QuantiFERON-TB-negative at baseline and developed disseminated tuberculosis during treatment with anti-tumour necrosis factor-α. Overall, 10.5% of this group of patients developed active tuberculosis; however, stratifying by biologic therapy, zero cases were observed among patients treated with anti-IL-17, -23, or -12/23 over a relatively long follow-up (48.1 months) A review of the available literature following our experience confirms the increased risk of tuberculosis reactivation with tumour necrosis factor-α inhibitors. Concerning anti-IL-23 and IL-17 drugs, available data showed high safety in patients at risk of tuberculosis reactivation. Screening of patients who should be taking IL-17 and IL-23 inhibitors is recommended for public health purposes. In case of a positive result with these therapies, consulting with an infectious diseases specialist is suggested in order to weigh up the risks and benefits of prophylactic treatment.

Exploring the association between Th17 pathway gene polymorphisms and pulmonary tuberculosis

Th17 cells play a key role in immunity against Mycobacterium tuberculosis (MTB), and this study aimed to explore the association of Th17 pathway gene polymorphisms with pulmonary tuberculosis (PTB) susceptibility in a Chinese population. A total of 10 single nucleotide polymorphisms in Th17 pathway genes (IL-17A gene rs2275913, rs3748067, rs8193036, rs3819024, IL-17F gene rs7741835, rs763780, IL-21 gene rs907715, rs2055979, IL-23R gene rs11805303, and rs7518660) were genotyped in 456 PTB patients and 466 controls using SNPscan technique. The IL-23R rs11805303 CC genotype, C allele frequencies were significantly lower in PTB patients than in controls, and the rs11805303 variant was significantly associated with the reduced risk of PTB in a recessive model. There were no significant associations between IL-17A, IL-17F, and IL-21 gene variations and PTB risk. In IL-17A gene, rs2275913, rs3748067, and rs3819024 variants were associated with drug resistance in PTB patients. In IL-17F gene, rs7741835 variant affected drug resistance, and rs763780 variant was associated with hypoproteinemia in PTB patients. In addition, the lower frequencies of the TT genotype, T allele of rs2055979 were found in PTB patients with drug-induced liver injury. Haplotype analysis showed that IL-23R CG haplotype frequency was significantly lower in PTB patients than in controls, while the TG haplotype frequency was higher. In conclusion, IL-23R rs11805303 polymorphism may contribute to the genetic underpinnings of PTB in the Chinese population, and the IL-17A, IL-17F, and IL-21 genetic variations are associated with several clinical manifestations of PTB patients.

Active pulmonary tuberculosis in a patient with secukinumab treatment

Numerous investigations have documented active tuberculosis (TB) infection following biologic treatment. One of the most secure biologic medications for infections is secukinumab. Additionally, no cases of active TB while receiving secukinumab therapy were recorded. Secukinumab 150 mg per month has been administered for a 19-year-old man with spondyloarthritis since May 2020. A diagnosis of pulmonary TB was made when the patient complained of a moderate fever, a productive cough, and weight loss after 2 years. His fever and respiratory symptoms were relieved after 6 weeks of treatment by stopping secukinumab and utilizing 4 antibiotics: isoniazid, rifampicin, pyrazinamide, and ethambutol, while non-steroidal anti-inflammatory drugs reduced his joint and back discomfort. During biological therapy, even with secukinumab, annual screening for latent and active TB is crucial. We require additional study on secukinumab-treated patients with active TB in nations with high TB burdens, including Vietnam.

Disseminated tuberculosis associated with deficient interleukin-23/tyrosine kinase 2 signalling

Tuberculosis (TB) remains a significant cause of morbidity and mortality globally. The disseminated form of the disease has a worse prognosis and is commonly associated with primary and acquired immunodeficiency states such as HIV/AIDS, post-organ transplant and malnutrition. However, disseminated TB in the context of isolated impaired cellular responses to interleukin (IL)-23 due to tyrosine kinase 2 (TYK2) deficiency has been rarely reported. We highlight the case of a young woman with pulmonary and central nervous system TB associated with previously undiagnosed IL-23/TYK2 signalling defects causing impaired response to IL-23. A significant clinical improvement was observed after introduction of adjunctive interferon-gamma therapy to her anti-tuberculous medications. This case emphasises the need to broadly evaluate for potential immune deficiencies in poorly responding patients with fully sensitive TB as well as the potential benefits of interferon-gamma therapy in patients with certain immune defects.

L-GSH Supplementation in Conjunction With Rifampicin Augments the Treatment Response to Mycobacterium tuberculosis in a Diabetic Mouse Model

Both active tuberculosis (TB) and asymptomatic latent Mycobacterium tuberculosis (M. tb) infection (LTBI) cause significant health burdens to humans worldwide. Individuals with immunocompromising health conditions, such as Type 2 Diabetes Mellitus (T2DM), have a weakened ability to control M. tb infection and are more susceptible to reactivation of LTBI to active diseases. T2DM cases are known to have glutathione (GSH) deficiency and impaired immune cell function, including the granulomatous response to M. tb infection. We have previously reported that liposomal glutathione (L-GSH) supplementation can restore the immune cell effector responses of T2DM cases. However, the effects of L-GSH supplementation on the bactericidal activities of first-line anti-TB drug rifampicin (RIF) against M. tb infection have yet to be explored. The aim of this study is to elucidate the effects of L-GSH supplementation in conjunction with RIF treatment during an active M. tb infection in a diabetic mouse model. In this study, we evaluated total and reduced levels of GSH, cytokine profiles, malondialdehyde (MDA) levels, M. tb burden, and granulomatous response in the lungs. We show that L-GSH supplementation caused a significant reduction in M. tb burden in the lungs, decreased oxidative stress, and increased the production of IFN-γ, TNF-α, IL-17, IL-10, and TGF-β1compared to the untreated mice. In addition, L-GSH supplementation in conjunction with RIF treatment achieved better control of M. tb infection in the lungs and significantly reduced the levels of oxidative stress compared to treatment with RIF alone. Moreover, L-GSH in conjunction with RIF significantly increased TGF-β1 levels compared to treatment with RIF alone. These findings suggest potential therapeutic benefits of L-GSH supplementation in conjunction with first-line antibiotic therapy against M. tb infection in individuals with T2DM.

Pro- and anti-inflammatory bioactive lipids imbalance contributes to the pathobiology of autoimmune diseases

Autoimmune diseases are driven by T_H17 cells that secrete pro-inflammatory cytokines, especially IL-17. Under normal physiological conditions, autoreactive T cells are suppressed by TGF-β and IL-10 secreted by microglia and dendritic cells. When this balance is upset due to injury, infection and other causes, leukocyte recruitment and macrophage activation occurs resulting in secretion of pro-inflammatory IL-6, TNF-α, IL-17 and PGE2, LTs (leukotrienes) accompanied by a deficiency of anti-inflammatory LXA4, resolvins, protecting, and maresins. PGE2 facilitates T_H1 cell differentiation and promotes immune-mediated inflammation through T_H17 expansion. There is evidence to suggest that autoimmune diseases can be suppressed by anti-inflammatory bioactive lipids LXA4, resolvins, protecting, and maresins. These results imply that systemic and/or local application of LXA4, resolvins, protecting, and maresins and administration of their precursors AA/EPA/DHA could form a potential therapeutic approach in the prevention and treatment of autoimmune diseases.

Dominant expansion of CD4+, CD8+ T and NK cells expressing Th1/Tc1/Type 1 cytokines in culture-positive lymph node tuberculosis

Lymph node culture-positive tuberculosis (LNTB+) is associated with increased mycobacterial antigen-induced pro-inflammatory cytokine production compared to LN culture-negative tuberculosis (LNTB-). However, the frequencies of CD4+, CD8+ T cells and NK cells expressing Th1/Tc1/Type 1 (IFNγ, TNFα, IL-2), Th17/Tc17/Type 17 (IL-17A, IL-17F, IL-22) cytokines and cytotoxic (perforin [PFN], granzyme [GZE] B, CD107a) markers in LNTB+ and LNTB- individuals are not known. Thus, we have studied the unstimulated (UNS) and mycobacterial antigen-induced frequencies of CD4+, CD8+ T and NK cells expressing Th1, Th17 cytokines and cytotoxic markers using flow cytometry. The frequencies of CD4+, CD8+ T and NK cells expressing cytokines and cytotoxic markers were not significantly different between LNTB+ and LNTB- individuals in UNS condition. In contrast, upon Mtb antigen stimulation, LNTB+ individuals are associated with significantly increased frequencies of CD4+ T cells (PPD [IFNγ, TNFα], ESAT-6 PP [IFNγ, TNFα], CFP-10 PP [IFNγ, TNFα, IL-2]), CD8+ T cells (PPD [IFNγ], ESAT-6 PP [IFNγ], CFP-10 PP [TNFα]) and NK cells (PPD [IFNγ, TNFα], ESAT-6 PP [IFNγ, TNFα], CFP-10 PP [TNFα]) expressing Th1/Tc1/Type 1, but not Th17/Tc17/Type 17 cytokines and cytotoxic markers compared to LNTB- individuals. LNTB+ individuals did not show any significant alterations in the frequencies of CD4+, CD8+ T cells and NK cells expressing cytokines and cytotoxic markers compared to LNTB- individuals upon HIV Gag PP and P/I antigen stimulation. Increased frequencies of CD4+, CD8+ T and NK cells expressing Th1/Tc1/Type 1 cytokines among the LNTB+ group indicates that the presence of mycobacteria plays a dominant role in the activation of key correlates of immune protection or induces higher immunopathology.

Liposomal Glutathione Helps to Mitigate Mycobacterium tuberculosis Infection in the Lungs

Mycobacterium tuberculosis (M. tb), the causative agent of tuberculosis (TB), is responsible for causing significant morbidity and mortality, especially among individuals with compromised immune systems. We have previously shown that the supplementation of liposomal glutathione (L-GSH) reduces M. tb viability and enhances a Th-1 cytokine response, promoting granuloma formation in human peripheral blood mononuclear cells in vitro. However, the effects of L-GSH supplementation in modulating the immune responses in the lungs during an active M. tb infection have yet to be explored. In this article, we report the effects of L-GSH supplementation during an active M. tb infection in a mouse model of pulmonary infection. We determine the total GSH levels, malondialdehyde (MDA) levels, cytokine profiles, granuloma formation, and M. tb burden in untreated and L-GSH-treated mice over time. In 40 mM L-GSH-supplemented mice, an increase in the total GSH levels was observed in the lungs. When compared to untreated mice, the treatment of M. tb-infected mice with 40 mM and 80 mM L-GSH resulted in a reduction in MDA levels in the lungs. L-GSH treatment also resulted in a significant increase in the levels of IL-12, IFN-γ, IL-2, IL-17, and TNF-α in the lungs, while down-regulating the production of IL-6, IL-10, and TGF-β in the lungs. A reduction in M. tb survival along with a decrease in granuloma size in the lungs of M. tb-infected mice was observed after L-GSH treatment. Our results show that the supplementation of mice with L-GSH led to increased levels of total GSH, which is associated with reduced oxidative stress, increased levels of granuloma-promoting cytokines, and decreased M. tb burden in the lung. These results illustrate how GSH can help mitigate M. tb infection and provide an insight into future therapeutic interventions.

Essential Fatty Acids and Their Metabolites in the Pathobiology of Inflammation and Its Resolution

Arachidonic acid (AA) metabolism is critical in the initiation and resolution of inflammation. Prostaglandin E2 (PGE2) and leukotriene B4/D4/E4 (LTB4/LD4/LTE4), derived from AA, are involved in the initiation of inflammation and regulation of immune response, hematopoiesis, and M1 (pro-inflammatory) macrophage facilitation. Paradoxically, PGE2 suppresses interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) production and triggers the production of lipoxin A4 (LXA4) from AA to initiate inflammation resolution process and augment regeneration of tissues. LXA4 suppresses PGE2 and LTs' synthesis and action and facilitates M2 macrophage generation to resolve inflammation. AA inactivates enveloped viruses including SARS-CoV-2. Macrophages, NK cells, T cells, and other immunocytes release AA and other bioactive lipids to produce their anti-microbial actions. AA, PGE2, and LXA4 have cytoprotective actions, regulate nitric oxide generation, and are critical to maintain cell shape and control cell motility and phagocytosis, and inflammation, immunity, and anti-microbial actions. Hence, it is proposed that AA plays a crucial role in the pathobiology of ischemia/reperfusion injury, sepsis, COVID-19, and other critical illnesses, implying that its (AA) administration may be of significant benefit in the prevention and amelioration of these diseases.

Immunological Assessment of Chitosan or Trimethyl Chitosan-Coated PLGA Nanospheres Containing Fusion Antigen as the Novel Vaccine Candidates Against Tuberculosis

The crucial challenge in tuberculosis (TB) as a chronic infectious disease is to present a novel vaccine candidate that improves current vaccination and provides efficient protection in individuals. The present study aimed to evaluate the immune efficacy of multi-subunit vaccines containing chitosan (CHT)- or trimethyl chitosan (TMC)-coated PLGA nanospheres to stimulate cell-mediated and mucosal responses against Mycobacterium Tuberculosis (Mtb) in an animal model. The surface-modified PLGA nanoparticles (NPs) containing tri-fusion protein from three Mtb antigens were produced by the double emulsion technique. The subcutaneously or nasally administered PLGA vaccines in the absence or presence of BCG were assessed to compare the levels of mucosal IgA, IgG1, and IgG2a production as well as secretion of IFN-γ, IL-17, IL-4, and TGF-β cytokines. According to the release profile, the tri-fusion encapsulated in modified PLGA NPs demonstrated a biphasic release profile including initial burst release on the first day and sustained release within 18 days. All designed PLGA vaccines induced a shift of Th1/Th2 balance toward Th1-dominant response. Although immunized mice through subcutaneous injection elicited higher cell-mediated responses relative to the nasal vaccination, the intranasally administered groups stimulated robust mucosal IgA immunity. The modified PLGA NPs using TMC cationic polymer were more efficient to elevate Th1 and mucosal responses in comparison with the CHT-coated PLGA nanospheres. Our findings highlighted that the tri-fusion loaded in TMC-PLGA NPs may represent an efficient prophylactic vaccine and can be considered as a novel candidate against TB.

Evaluation of CD8+ T cell subpopulations in paracoccidioidomycosis

Aim: We aimed to verify the frequency of CD8⁺ T cell subsets in patients with acute form and chronic form of paracoccidioidomycosis. Material & Methods: Mononuclear cells from paracoccidioidomycosis patients and healthy donors were isolated and phenotyped by flow cytometry. Dendritic cells were pulsed with Paracoccidioides brasiliensis yeast and co-cultures with lymphocytes. Cytokine production was measured by ELISA. Results: Acute form patients present a higher frequency of Tc1 and Tc10 cells, while chronic form patients have more Tc1 and Tc21 cells, compared with healthy controls. In vitro assays showed that P. brasiliensis induced polarization to the Tc17/Tc22 subsets. Conclusion: Our results suggest that CD8⁺ T cells can respond in a similar way to P. brasiliensis infection, regardless of the clinical presentation of the disease.

[Effect of Soy Sauce, Fish Sauce for Nitrite Determination in Meat Products]

The diazotization method is used for nitrite determination in meat products. In this method, it is known that the presence of reducing substances such as ascorbic acid and cysteine in the sample interferes with nitrite determination. We speculated that soy sauce, fish sauce and mirin, which are used in meat products, might be the reducing substances, so investigated meat products which contain soy sauce and other ingredients. The results showed that quantitative disturbance was observed in soy sauce and fish sauce, and the recovery in spiked samples of these products decreased in proportion to the increase in soy sauce and fish sauce content. However the antioxidant of soy sauce and fish sauce depending on manufacturing methods, so quantitative disturbance dose not be observed each time, so nitrite determination in meat products, and to conduct simultaneous determination using different sample amounts to confirm whether there is any difference in the quantitative values.

Association of Secukinumab Treatment With Tuberculosis Reactivation in Patients With Psoriasis, Psoriatic Arthritis, or Ankylosing Spondylitis

Question

What is the association of secukinumab with active tuberculosis (TB) development, TB reactivation, and latent tuberculosis infection (LTBI) activation?

Findings

In this pooled cohort study of 12 319 patients with psoriasis, psoriatic arthritis, or ankylosing spondylitis, spontaneous reporting of new LTBI while undergoing secukinumab treatment was rare. No active cases of TB or LTBI reactivation were reported.

Meaning

The findings of this study provide a broader understanding of the safety of secukinumab and appear to support its long-term use in chronic systemic inflammatory conditions.

Importance

Approximately one-quarter of the global population have latent tuberculosis infection (LTBI), and tuberculosis (TB) is accountable for more than 1.5 million deaths annually. Methotrexate, cyclosporine, and tumor necrosis factor inhibitors may be associated with increased risk of TB and LTBI reactivation, although data are limited on the risks of TB with use of newer biologics.

Objective

To assess the association of secukinumab with reporting of active TB development, TB reactivation, and LTBI activation as an adverse event (AE) in patients with psoriasis, psoriatic arthritis, or ankylosing spondylitis.

Design, Setting, and Participants

This pooled cohort study pooled data from 28 clinical trials of secukinumab used in psoriasis (17 phase 3 or 3b and 2 phase 4 trials), psoriatic arthritis (5 phase 3 trials), and ankylosing spondylitis (4 phase 3 trials). A search of the Novartis Secukinumab Compound Pool Database was conducted for the 28 trials. All trial participants who had received at least 1 approved subcutaneous dose of secukinumab (150 mg or 300 mg) were included. Before randomization in these trials, patients underwent screening for TB. Patients with active TB were excluded, and patients with LTBI were treated according to local guidelines. Data were analyzed from the start of treatment in the individual studies through December 25, 2018.

Main Outcomes and Measures

Reporting of active TB or LTBI as an AE over a 5-year period using exposure-adjusted incidence rates (EAIR; incidence rates per 100 patient-years).

Results

A total of 12 319 patients were included, of whom 8819 patients had psoriasis (71.6%; 5930 men [67.2%]; mean [SD] age, of 44.9 [13.5] years), 2523 had psoriatic arthritis (20.5%; 1323 women [52.4%]; mean [SD] age, 48.8 [12.1] years), and 977 had ankylosing spondylitis (7.3%; 658 men [67.3%]; mean [SD] age, 42.3 [11.9] years). In the total population, 684 patients (5.6%) had tested positive for LTBI at screening. Over 5 years, LTBI as an AE during secukinumab treatment was reported in 13 patients (0.1% of 12 319). Of these 13 patients, 6 had a prior positive LTBI test result, and 7 were newly diagnosed as having LTBI. Four of the 7 patients had psoriasis (EAIR, 0.03; 95% CI, 0.01-0.07), 1 had psoriatic arthritis (EAIR, 0.02; 95% CI, 0.00-0.11), and 2 had ankylosing spondylitis (EAIR, 0.08; 95% CI, 0.01-0.28). No cases of active TB were reported.

Conclusions and Relevance

This study found that LTBI reported as an AE after secukinumab treatment was uncommon and appeared to support the use of secukinumab in chronic systemic inflammatory conditions.

Functional Analysis of Immune Signature Genes in Th1* Memory Cells Links ISOC1 and Pyrimidine Metabolism to IFN-γ and IL-17 Production

CCR6+CXCR3+CCR4-CD4+ memory T cells, termed Th1*, are important for long-term immunity to Mycobacterium tuberculosis and the pathogenesis of autoimmune diseases. Th1* cells express a unique set of lineage-specific transcription factors characteristic of both Th1 and Th17 cells and display distinct gene expression profiles compared with other CD4+ T cell subsets. To examine molecules and signaling pathways important for the effector function of Th1* cells, we performed loss-of-function screening of genes selectively enriched in the Th1* subset. The genetic screen yielded candidates whose depletion significantly impaired TCR-induced IFN-γ production. These included genes previously linked to IFN-γ or M. tuberculosis susceptibility and novel candidates, such as ISOC1, encoding a metabolic enzyme of unknown function in mammalian cells. ISOC1-depleted T cells, which produced less IFN-γ and IL-17, displayed defects in oxidative phosphorylation and glycolysis and impairment of pyrimidine metabolic pathway. Supplementation with extracellular pyrimidines rescued both bioenergetics and IFN-γ production in ISOC1-deficient T cells, indicating that pyrimidine metabolism is a key driver of effector functions in CD4+ T cells and Th1* cells. Results provide new insights into the immune-stimulatory function of ISOC1 as well as the particular metabolic requirements of human memory T cells, providing a novel resource for understanding long-term T cell-driven responses.

Classical CD4 T cells as the cornerstone of antimycobacterial immunity

Tuberculosis is a significant health problem without an effective vaccine to combat it. A thorough understanding of the immune response and correlates of protection is needed to develop a more efficient vaccine. The immune response against Mycobacterium tuberculosis (Mtb) is complex and involves all aspects of the immune system, however, the optimal protective, non‐pathogenic T cell response against Mtb is still elusive. This review will focus on discussing CD4 T cell immunity against mycobacteria and its importance in Mtb infection with a primary focus on human studies. We will in particular discuss the large heterogeneity of immune cell subsets that have been revealed by recent immunological investigations at an unprecedented level of detail. These studies have identified specific classical CD4 T cell subsets important for immune responses against Mtb in various states of infection. We further discuss the functional attributes that have been linked to the various subsets such as upregulation of activation markers and cytokine production. Another important topic to be considered is the antigenic targets of Mtb‐specific immune responses, and how antigen reactivity is influenced by both disease state and environmental exposure(s). These are key points for both vaccines and immune diagnostics development. Ultimately, these factors are holistically considered in the definition and investigations of what are the correlates on protection and resolution of disease.

Use of IL-23 Inhibitors for the Treatment of Plaque Psoriasis and Psoriatic Arthritis: A Comprehensive Review

Psoriasis is a common inflammatory skin disease with multiple comorbidities, including psoriatic arthritis and coronary artery disease, that can severely impact an individual’s quality of life and daily functioning. In recent years, enhanced understanding of the pathogenesis of psoriasis, especially the role of T helper 17 cells, has resulted in the development of new classes of biologic drugs targeting modulators along its disease pathway. Among these, inhibitors of interleukin-23 (e.g., ustekinumab, guselkumab, tildrakizumab, and risankizumab) have emerged as safe and effective options for the treatment of moderate-to-severe plaque psoriasis; ustekinumab and guselkumab have additionally been approved to treat psoriatic arthritis. Selective interleukin-23 inhibitors require less frequent dosing than interleukin-17 inhibitors and may possess a more favorable risk profile without an increased risk of candidiasis or inflammatory bowel disease. Overall, these highly effective medications are contributing to a rising standard for psoriasis outcomes through resolution of skin lesions and joint manifestations and improvement of patient quality of life.

Intranasal immunization with peptide-based immunogenic complex enhances BCG vaccine efficacy in a murine model of tuberculosis

Prime-boost immunization strategies are required to control the global tuberculosis (TB) pandemic, which claims approximately 3 lives every minute. Here, we have generated an immunogenic complex against Mycobacterium tuberculosis (M.tb), consisting of promiscuous T cell epitopes (M.tb peptides) and TLR ligands assembled in liposomes. Interestingly, this complex (peptide–TLR agonist–liposomes; PTL) induced significant activation of CD4⁺ T cells and IFN-γ production in the PBMCs derived from PPD⁺ healthy individuals as compared with PPD^– controls. Furthermore, intranasal delivery of PTL significantly reduced the bacterial burden in the infected mice by inducing M.tb-specific polyfunctional (IFN-γ⁺IL-17⁺TNF-α⁺IL-2⁺) immune responses and long-lasting central memory responses, thereby reducing the risk of TB recurrence in DOTS-treated infected animals. The transcriptome analysis of peptide-stimulated immune cells unveiled the molecular basis of enhanced protection. Furthermore, PTL immunization significantly boosted the Bacillus Calmette-Guerin–primed (BCG-primed) immune responses against TB. The greatly enhanced efficacy of the BCG-PTL vaccine model in controlling pulmonary TB projects PTL as an adjunct vaccine against TB.

Proteomic analysis reveals critical molecular mechanisms involved in the macrophage anti-spinal tuberculosis process

Tuberculosis infection activates the autoimmune system. However, the role of host-pathogen interactions involved in Mycobacterium tuberculosis infection is unclear. In this study, we analyzed 6 spinal tuberculosis tissues and 6 herniated disc tissues by using liquid chromatography-tandem mass spectrometry coupled with tandem mass spectrometry, and immunohistochemical staining was performed for validating the results. We identified 42 differential immune-related proteins and 3 hub genes that are primarily localised in the tertiary granule and involved in biological processes such as cellular response to the presence of cadmium ions, regulation of ion transmembrane transport, transmembrane transport, and inflammatory responses. Genes encoding cytochrome B-245 beta chain (CYBB), matrix metallopeptidase 9 (MMP9), and C-X-C motif chemokine ligand 10 (CXCL10) were identified as the hub genes that exhibited anti-tuberculosis activity and were responsible for macrophage resistance against M. tuberculosis. In conclusion, CYBB, MMP9, and CXCL10 resist M. tuberculosis infection through chemotaxis and macrophage activation. Our results indicate that CYBB, MMP9, and CXCL10 could be considered as molecular targets for spinal tuberculosis treatment, which may significantly improve patients' quality of life and prognosis.

Diagnosis by molecular pathology of an early and atypical histoplasmosis lesion in the duodenum of an immunocompromised patient: A case report

Histoplasmosis is a fungal infection caused by Histoplasma capsulatum (HC), which can occasionally be aggressive resulting in the formation of granulomatous lesions. These are usually located in the lungs; however, immunocompromised patients may occasionally develop disseminated lesions in other organs as well. Human immunodeficiency virus (HIV) primarily infects cells of the immune system expressing CD4 molecules. Not only does HIV multiply within these cells, but it can also kill them or otherwise cause loss of cellular function, leading to an immunocompromised state. As a result, in an immunocompromised patient, infection with HC can have serious implications, often the development of visceral histoplasmosis in different organs. Although several types of lesions are formed in HC-infected organs, it may be difficult to distinguish the causative organism from other pathogens based on morphology alone. The present case report describes the case of a 57-year-old woman, from South America, who may have been infected with HC >20 years previously, remaining asymptomatic over the years. She later developed a lesion in the duodenum associated with immunodeficiency caused by HIV infection. The differential diagnosis of this case was made on the basis of several specific morphological findings using histopathological analysis and molecular pathological techniques. The pathogenesis of characteristic lesions caused by HC in the presence of HIV infection was also reviewed.

Risk of tuberculosis reactivation with interleukin (IL)-17 and IL-23 inhibitors in psoriasis - time for a paradigm change

Tuberculosis is an infectious disease with a major global impact, ranked in the top 10 mortality causes worldwide. In an immunocompetent individual, the host defence mechanisms control Mycobacterium tuberculosis infection and induce the latent form of the disease. However, in the presence of diseases or therapies, which exert an immunosuppressive effect, latent tuberculosis can be re-activated. Psoriasis is an immune-mediated, inflammatory disease, and its treatment has rapidly evolved over the last few years. It has long been recognized that the tumour necrosis factor (TNF)-α inhibitors are associated with increased risk of reactivation of latent tuberculosis infection. Thus, international guidelines have been suggesting tuberculosis screening before starting the treatment with all biological agents since then. In addition, the institution of chemoprophylaxis in the presence of latent tuberculosis and the annual screening for tuberculosis thereafter have also been indicated. However, anti-tuberculosis treatments can have significant side-effects and there are currently several contraindications to their use. The risk benefit of starting anti-tuberculous treatment should be carefully weighed up. The emergence of new biological drugs for the treatment of psoriasis, such as interleukin (IL)-17 and IL-23 inhibitors, has reignited the subject of tuberculosis reactivation as it is possible that IL-17 and 23 blockade do not carry the same risk of TB reactivation as TNF-α inhibitors. Although preclinical studies have shown that cytokines IL-17 and IL-23 have a possible role against infection with M. tuberculosis, data from clinical trials and post-marketing surveillance with drugs that inhibit these cytokines appear to suggest that they are not crucial to this response. In this article, we review the available data on tuberculosis reactivation after the treatment of psoriasis with IL-17 and IL-23 inhibitors, and its possible impact on the way we currently manage latent tuberculosis infection before or after starting treatment with these new drugs.

Parasite-bacteria interrelationship

Parasites and bacteria have co-evolved with humankind, and they interact all the time in a myriad of ways. For example, some bacterial infections result from parasite-dwelling bacteria as in the case of Salmonella infection during schistosomiasis. Other bacteria synergize with parasites in the evolution of human disease as in the case of the interplay between Wolbachia endosymbiont bacteria and filarial nematodes as well as the interaction between Gram-negative bacteria and Schistosoma haematobium in the pathogenesis of urinary bladder cancer. Moreover, secondary bacterial infections may complicate several parasitic diseases such as visceral leishmaniasis and malaria, due to immunosuppression of the host during parasitic infections. Also, bacteria may colonize the parasitic lesions; for example, hydatid cysts and skin lesions of ectoparasites. Remarkably, some parasitic helminths and arthropods exhibit antibacterial activity usually by the release of specific antimicrobial products. Lastly, some parasite-bacteria interactions are induced as when using probiotic bacteria to modulate the outcome of a variety of parasitic infections. In sum, parasite-bacteria interactions involve intricate processes that never cease to intrigue the researchers. However, understanding and exploiting these interactions could have prophylactic and curative potential for infections by both types of pathogens.

6,6'-Aryl trehalose analogs as potential Mincle ligands

6,6'-Aryl trehalose derivatives have been synthesized with a view towards identifying novel Th-17-inducing vaccine adjuvants based on the high affinity Mincle ligand Brartemicin. The initial structure-activity relationships of these novel trehalose-based compounds were investigated. All compounds have been evaluated for their ability to engage the Mincle receptor and induce a potential pro-Th17 cytokine profile from human peripheral blood mononuclear cells based on IL-6 production in human peripheral blood mononuclear cells. The preliminary biological characterization of the designed analogs presented in this paper should aid in the future design and testing of more affine ligands that may foster the discovery of novel adjuvants with improved pharmacological properties.

Lack of Evidence for an Association between IL-17F Rs763780 Polymorphism and Pulmonary Tuberculosis

The relationship between the interleukin-17F (IL-17F) rs763780 polymorphism and tuberculosis (TB) has been a source of debate. The potential association between the IL-17F rs763780 polymorphism and TB was investigated using a meta-analysis of case-control studies, which were obtained using the EMBASE, PubMed, CNKI, Scopus, and Web of Science databases. Heterogeneity across studies was evaluated, and summary odds ratios and 95% confidence intervals were computed to estimate a summary effect size using either a fixed-effects or random-effects model. Eight eligible studies comprising nine comparisons for the IL-17F rs763780 polymorphism (3824 cases and 3787 controls) were obtained for this meta-analysis. Although a significant relationship between IL-17F rs763780 and TB susceptibility was observed using the allele genetic model (odds ratio = 1.34, 95% confidence interval = 1.04-1.74), there was high heterogeneity among the studies (I2 = 79%, P=0.0001). The stratified analyses by race, type of tuberculosis, and Hardy-Weinberg equilibrium suggested that the IL-17F rs763780 polymorphism was not associated with risk of pulmonary tuberculosis and the heterogeneity disappeared. Hardy-Weinberg equilibrium is the main cause of the heterogeneity. No evidence was found through this meta-analysis that suggested an association between the IL-17F rs763780 polymorphism and risk of pulmonary tuberculosis.

Clofazimine enhances the efficacy of BCG revaccination via stem cell-like memory T cells

Tuberculosis (TB) is one of the deadliest diseases, claiming ~2 million deaths annually worldwide. The majority of people in TB endemic regions are vaccinated with Bacillus Calmette Guerin (BCG), which is the only usable vaccine available. BCG is efficacious against meningeal and disseminated TB in children, but protective responses are relatively short-lived and fail to protect against adult pulmonary TB. The longevity of vaccine efficacy critically depends on the magnitude of long-lasting central memory T (T_CM) cells, a major source of which is stem cell-like memory T (T_SM) cells. These T_SM cells exhibit enhanced self-renewal capacity as well as to rapidly respond to antigen and generate protective poly-functional T cells producing IFN-γ, TNF-α, IL-2 and IL-17. It is now evident that T helper Th 1 and Th17 cells are essential for host protection against TB. Recent reports have indicated that Th17 cells preserve the molecular signature for T_SM cells, which eventually differentiate into IFN-γ-producing effector cells. BCG is ineffective in inducing Th17 cell responses, which might explain its inadequate vaccine efficacy. Here, we show that revaccination with BCG along with clofazimine treatment promotes T_SM differentiation, which continuously restores T_CM and T effector memory (T_EM) cells and drastically increases vaccine efficacy in BCG-primed animals. Analyses of these T_SM cells revealed that they are predominantly precursors to host protective Th1 and Th17 cells. Taken together, these findings revealed that clofazimine treatment at the time of BCG revaccination provides superior host protection against TB by increasing long-lasting T_SM cells.

Tuberculosis (TB) is one of the deadliest diseases, claiming ~2 million deaths annually worldwide. Bacillus Calmette Guerin (BCG) is the only usable vaccine available and exhibits efficacy against meningeal and disseminated TB in children. Consequently, the vast majority of people in TB endemic regions are vaccinated with BCG. However, host protective immune responses diminish over time due to gradual depletion of T central memory (T_CM) cells, which are responsible for long-term host protection. Here, we provide evidence that revaccination with BCG along with the clofazimine, an approved drug for treatment of leprosy and drug-resistant TB, induces stem cell-like memory T (T_SM) cells. T_SM cells are precursors to T_CM cells, and provide long-term host protection to TB by continuous supply of T_CM cells. Interestingly, these T_SM cells were generated from IL-17-producing T helper (Th)17 cells. These T_SM cells differentiated into T_CM and T effector memory (T_EM) cells and maintained a stable pool of critically important Th1 and Th17 cells to provide optimal host protection against TB.

Tuberculosis vaccine: A journey from BCG to present

Tuberculosis (TB) is the leading cause of death worldwide due to an infectious disease, causing around 1.6 million deaths each year. This situation has become more complicated by the emergence of drug-resistant Mycobacterium tuberculosis (M.tb) and HIV-TB co-infection, which has significantly worsened TB prognosis and treatment. Despite years of intensive research, Bacille Calmette-Guerin (BCG) remains the only licensed vaccine and has variable efficacy. It provides protection against childhood TB but is not effective in adult pulmonary TB. As a result of intense research in understanding TB vaccinology, there are many new vaccine candidates in clinical development and many more in pre-clinical trials which aim either to replace or boost BCG vaccine. This review discusses the history of BCG vaccine development and summarizes limitations of the current vaccine strategy and recent advances in improving BCG immunization along with other new vaccines in clinical trials which are promising candidates for the future tuberculosis vaccinology program.

Tools for Assessing the Protective Efficacy of TB Vaccines in Humans: in vitro Mycobacterial Growth Inhibition Predicts Outcome of in vivo Mycobacterial Infection

Tuberculosis (TB) remains a leading global cause of morbidity and mortality and an effective new vaccine is urgently needed. A major barrier to the rational development of novel TB vaccines is the lack of a validated immune correlate or biomarker of protection. Mycobacterial Growth Inhibition Assays (MGIAs) provide an unbiased measure of ability to control mycobacterial growth in vitro, and may represent a functional correlate of protection. However, the biological relevance of any potential correlate can only be assessed by determining the association with in vivo protection from either a controlled mycobacterial infection or natural development of TB disease. Our data demonstrate that the direct MGIA using peripheral blood mononuclear cells (PBMC) is measuring a biologically relevant response that correlates with protection from in vivo human BCG infection across two independent cohorts. This is the first report of an MGIA correlating with in vivo protection in the species-of-interest, humans, and furthermore on a per-individual as well as per-group basis. Control of mycobacterial growth in the MGIA is associated with a range of immune parameters measured post-BCG infection in vivo including the IFN-γ ELISpot response, frequency of PPD-specific IFN-γ or TNF-α producing CD4+ T cells and frequency of specific sub-populations of polyfunctional CD4+ T cells. Distinct transcriptomic profiles are associated with good vs. poor mycobacterial control in the MGIA, with good controllers showing enrichment for gene sets associated with antigen processing/presentation and the IL-23 pathway, and poor controllers showing enrichment for hypoxia-related pathways. This study represents an important step toward biologically validating the direct PBMC MGIA for use in TB vaccine development and furthermore demonstrates the utility of this assay in determining relevant immune mechanisms and pathways of protection.

Aryl Trehalose Derivatives as Vaccine Adjuvants for Mycobacterium tuberculosis

Mycobacterium tuberculosis (Mtb) continues to be a major health threat worldwide, and the development of Mtb vaccines could play a pivotal role in the prevention and control of this devastating epidemic. Th17-mediated immunity has been implicated in disease protection correlates of immune protection against Mtb. Currently, there are no approved adjuvants capable of driving a Th17 response in a vaccine setting. Recent clinical trial results using trehalose dibehenate have demonstrated a formulation-dependant proof of concept adjuvant system CAF01 capable of inducing long-lived protection. We have discovered a new class of Th17-inducing vaccine adjuvants based on the natural product Brartemicin. We synthesized and evaluated the capacity of a library of aryl trehalose derivatives to drive immunostimulatory reresponses and evaluated the structure-activity relationships in terms of the ability to engage the Mincle receptor and induce production of innate cytokines from human and murine cells. We elaborated on the structure-activity relationship of the new scaffold and demonstrated the ability of the lead entity to induce a pro-Th17 cytokine profile from primary human peripheral blood mononuclear cells and demonstrated efficacy in generating antibodies in combination with tuberculosis antigen M72 in a mouse model.

The role of B cells in an early immune response to Mycobacterium bovis

Mycobacterium tuberculosis is the main etiological agent of tuberculosis. The Bacillus Calmette-Guérin (BCG) microbes that are primarily used as a vaccine against tuberculosis also constitute the dominant infection model for studying the interaction of mycobacteria with the host cell types. The majority of interaction experiments have been conducted using macrophages and monocytes as prototype phagocyte cell types. Here, we report that M. bovis BCG infects mouse primary B cells as well as human B cell line. The complement receptors, along with B cell receptors, are engaged in the process of bacterial entry into the host B cells. Once inside the B cells, the intracellular trafficking of BCG follows the complete endocytic pathway of the ingested particles, which is in contrast to the events taking place during ingestion of BCG by macrophages. In vivo infection of mice with M. bovis BCG activated peritoneal as well as splenic B cells to produce proinflammatory cytokines. This paper further supports the evidence that B cells are involved in a host's early interactions with intracellular bacterial pathogens and participate in the induction of innate defense responses.

Eosinophil Polymorphonuclear Leukocytes in TB: What We Know so Far

Knowledge on the cellular immune responses to infection with Mycobacterium tuberculosis has improved drastically in recent years. Though eosinophils and hypereosinophilia are linked with the disease process of tuberculosis, there is paucity of information to prove the actual role played by these polymorphonuclear leukocytes. The aim of this review is to provide an overview of the existing literature on what is known so far about eosinophils and tuberculosis.

PI3-Kinase δγ Catalytic Isoforms Regulate the Th-17 Response in Tuberculosis

Although IL17A plays a protective role at the mucosal surface, when IL17A signaling becomes dysregulated, a pathological response is locally induced. At the early stages of Mycobacterium tuberculosis (M.tb) infection, IL17A contributes to granuloma formation and pathogen containment. In contrast, during disease progression, a dysregulated IL17A hyperinflammatory response drives tissue destruction through enhanced neutrophil recruitment. Cumulative research has implicated the PI3-Kinase pathways as one of the most relevant in the pathophysiology of inflammation. Evidence shows that IL-17A secretion and the expansion of the Th17 population is dependant in PI3-Kinase signaling, with the p110δ and p110γ isoforms playing a prominent role. The p110γ isoform promotes disease progression through dampening of the Th17 response, preventing pathogen clearance and containment. The p110γ gene, PIK3CG is downregulated in TB patients during late-stage disease when compared to healthy controls, demonstrating an important modulatory role for this isoform during TB. Conversely, the p110δ isoform induces IL-17A release from pulmonary γδ T-cells, committed Th17 cells and promotes neutrophil recruitment to the lung. Inhibiting this isoform not only suppresses IL-17A secretion from Th17 cells, but it also inhibits cytokine production from multiple T-helper cell types. Since increased IL-17A levels are observed to be localized in the lung compartments (BAL and lymphocytes) in comparison to circulating levels, an inhalable PI3Kδ inhibitor, which is currently utilized for inflammatory airway diseases characterized by IL-17A over-secretion, may be a therapeutic option for active TB disease.

Curcumin Nanoparticles Enhance Mycobacterium bovis BCG Vaccine Efficacy by Modulating Host Immune Responses

Tuberculosis (TB) is one of the deadliest diseases, causing ∼2 million deaths annually worldwide. Mycobacterium bovis bacillus Calmette-Guérin (BCG), the only TB vaccine in common use, is effective against disseminated and meningeal TB in young children but is not effective against adult pulmonary TB.

Tuberculosis (TB) is one of the deadliest diseases, causing ∼2 million deaths annually worldwide. Mycobacterium bovis bacillus Calmette-Guérin (BCG), the only TB vaccine in common use, is effective against disseminated and meningeal TB in young children but is not effective against adult pulmonary TB. T helper 1 (Th1) cells producing interferon gamma (IFN-γ) and Th17 cells producing interleukin-17 (IL-17) play key roles in host protection against TB, whereas Th2 cells producing IL-4 and regulatory T cells (Tregs) facilitate TB disease progression by inhibiting protective Th1 and Th17 responses. Furthermore, the longevity of vaccine efficacy critically depends on the magnitude of long-lasting central memory T (T_CM) cell responses. Hence, immunomodulators that promote T_CM responses of the Th1 and Th17 cell lineages may improve BCG vaccine efficacy. Here, we show that curcumin nanoparticles enhance various antigen-presenting cell (APC) functions, including autophagy, costimulatory activity, and the production of inflammatory cytokines and other mediators. We further show that curcumin nanoparticles enhance the capacity of BCG to induce T_CM cells of the Th1 and Th17 lineages, which augments host protection against TB infection. Thus, curcumin nanoparticles hold promise for enhancing the efficacy of TB vaccines.

The Non-synonymous rs763780 Single-Nucleotide Polymorphism in IL17F Gene Is Associated With Susceptibility to Tuberculosis and Advanced Disease Severity in Argentina

Th17 lymphocytes, that produce IL17A, IL17F, and IL22, play a crucial role during the immune response against Mycobacterium tuberculosis (Mtb) infection. Whereas, the contribution of IL17A in immunity to tuberculosis is usually accepted, the role of IL17F has been scarcely studied so far. The aim of this work was to evaluate the existence of a potential association of the non-synonymous variant rs763780 SNP of the IL17F gene with human tuberculosis. Accordingly, by comparing healthy donors (HD) and tuberculosis patients (TB) populations we demonstrated an association between the C allele of the SNP and the susceptibility to tuberculosis disease in Argentina. Furthermore, we found that peripheral blood mononuclear cells (PBMCs) from individuals with a more effective immune response against Mtb secreted the highest levels of IL17F when stimulated with a lysate of Mtb (Mtb-Ag). Besides, we evidenced that Mtb-Ag-stimulated PBMCs from HD carrying the C variant of the SNP displayed the lowest IFNG secretion, proliferation index, and SLAM expression as compared to TT carriers. Moreover, Mtb-Ag-stimulated PBMCs from TB carrying the C allele produced the lowest levels of IFNG, the highest level of IL17A, and the minimum proliferation indexes as compared to TT TB, suggesting a relationship between the C allele and tuberculosis severity. In fact, TB carrying the C allele presented a more severe disease, with the highest bacilli burden in sputum. Together, our findings identify the IL17F rs763780 SNP as a biomarker of tuberculosis susceptibility and advanced disease severity in Argentina, suggesting that IL17F could be a critical cytokine in tuberculosis immunity.

Diminished type 1 and type 17 cytokine expressing - Natural killer cell frequencies in tuberculous lymphadenitis

Tuberculous lymphadenitis (TBL) is associated with the expansion of CD4⁺ and CD8⁺ T cells expressing Type 1 and Type 17 cytokines in the peripheral blood. However, the expression pattern of cytokine producing natural killer (NK) cells in both the peripheral blood and affected lymph nodes i.e. site of infection in TBL have not been examined. Hence, we have analyzed the baseline and mycobacterial antigen specific NK cell cytokine frequencies in whole blood of TBL and pulmonary tuberculosis (PTB) individuals. We have also examined the NK cell frequencies before and after treatment completion and in peripheral blood versus affected lymph nodes (LN) of TBL individuals. TBL is characterized by diminished frequencies of NK cells expressing Type 1 (IFNγ, TNFα), Type 17 (IL-17F) cytokines compared to PTB individuals upon antigen-specific stimulation. In contrast, TBL individuals did not exhibit any significant differences in the frequencies of NK cells expressing Type 1 and Type 17 cytokines upon completion of anti-tuberculosis treatment. LN of TBL is associated with altered frequencies of NK cells expressing Type 17 (increased IL-17F and decreased IL-22) cytokines when compared to peripheral blood. Thus, we conclude that TBL individuals are characterized by diminished frequencies of NK cells expressing Type 1/Type 17 cytokines.

Revisiting the Concept of Targeting NFAT to Control T Cell Immunity and Autoimmune Diseases

The nuclear factor of activated T cells (NFAT) family of transcription factors, which includes NFAT1, NFAT2, and NFAT4, are well-known to play important roles in T cell activation. Most of NFAT proteins are controlled by calcium influx upon T cell receptor and costimulatory signaling results increase of IL-2 and IL-2 receptor. NFAT3 however is not shown to be expressed in T cells and NFAT5 has not much highlighted in T cell functions yet. Recent studies demonstrate that the NFAT family proteins involve in function of lineage-specific transcription factors during differentiation of T helper 1 (Th1), Th2, Th17, regulatory T (Treg), and follicular helper T cells (Tfh). They have been studied to make physical interaction with the other transcription factors like GATA3 or Foxp3 and they also regulate Th cell signature gene expressions by direct binding on promotor region of target genes. From last decades, NFAT functions in T cells have been targeted to develop immune modulatory drugs for controlling T cell immunity in autoimmune diseases like cyclosporine A, FK506, etc. Due to their undesirable side defects, only limited application is available in human diseases. This review focuses on the recent advances in development of NFAT targeting drug as well as our understanding of each NFAT family protein in T cell biology. We also discuss updated detail molecular mechanism of NFAT functions in T cells, which would lead us to suggest an idea for developing specific NFAT inhibitors as a therapeutic drug for autoimmune diseases.

The Influence of Parasite Infections on Host Immunity to Co-infection With Other Pathogens

Parasites have evolved a wide range of mechanisms that they use to evade or manipulate the host's immune response and establish infection. The majority of the in vivo studies that have investigated these host-parasite interactions have been undertaken in experimental animals, especially rodents, which were housed and maintained to a high microbiological status. However, in the field situation it is increasingly apparent that pathogen co-infections within the same host are a common occurrence. For example, chronic infection with pathogens including malarial parasites, soil-transmitted helminths, Mycobacterium tuberculosis and viruses such as HIV may affect a third of the human population of some developing countries. Increasing evidence shows that co-infection with these pathogens may alter susceptibility to other important pathogens, and/or influence vaccine efficacy through their effects on host immune responsiveness. Co-infection with certain pathogens may also hinder accurate disease diagnosis. This review summarizes our current understanding of how the host's immune response to infection with different types of parasites can influence susceptibility to infection with other pathogenic microorganisms. A greater understanding of how infectious disease susceptibility and pathogenesis can be influenced by parasite co-infections will enhance disease diagnosis and the design of novel vaccines or therapeutics to more effectively control the spread of infectious diseases.

A lipidated bi-epitope vaccine comprising of MHC-I and MHC-II binder peptides elicits protective CD4 T cell and CD8 T cell immunity against Mycobacterium tuberculosis

Background

The clinical trials conducted at Chingleput India suggest that BCG fails to protect against tuberculosis (TB) in TB-endemic population. Recent studies advocate that non-tuberculous mycobacteria and latent Mycobacterium tuberculosis (Mtb) infection interferes in the antigen processing and presentation of BCG in inducing protective immunity against Mtb. Thereby, indicating that any vaccine that require extensive antigen processing may not be efficacious in TB-endemic zones. Recently, we have demonstrated that the vaccine candidate L91, which is composed of lipidated promiscuous MHC-II binder epitope, derived from latency associated Acr1 antigen of Mtb is immunogenic in the murine and Guinea pig models of TB and conferred better protection than BCG against Mtb.

Methods

In this study, we have used a multi-stage based bi-epitope vaccine, namely L4.8, comprising of MHC-I and MHC-II binding peptides of active (TB10.4) and latent (Acr1) stages of Mtb antigens, respectively. These peptides were conjugated to the TLR-2 agonist Pam2Cys.

Results

L4.8 significantly elicited both CD8 T cells and CD4 T cells immunity, as evidenced by increase in the enduring polyfunctional CD8 T cells and CD4 T cells. L4.8 efficiently declined Mtb-burden and protected animals better than BCG and L91, even at the late stage of Mtb infection.

Conclusions

The BCG-L4.8 prime boost strategy imparts a better protection against TB than the BCG alone. This study emphatically denotes that L4.8 can be a promising future vaccine candidate for controlling active and latent TB.

Electronic supplementary material

The online version of this article (10.1186/s12967-018-1653-x) contains supplementary material, which is available to authorized users.

Cell death at the cross roads of host-pathogen interaction in Mycobacterium tuberculosis infection

Tuberculosis (TB) continues to be the leading cause of death by any single infectious agent, accounting for around 1.7 million annual deaths globally, despite several interventions and support programs by national and international agencies. With the development of drug resistance in Mycobacterium tuberculosis (M. tb), there has been a paradigm shift in TB research towards host-directed therapy. The potential targets include the interactions between host and bacterial proteins that are crucial for pathogenesis. Hence, collective efforts are being made to understand the molecular details of host-pathogen interaction for possible translation into host-directed therapy. The present review focuses on 'host cell death modalities' of host-pathogen interaction, which play a crucial role in determining the outcome of TB disease progression. Several cell death modalities that occur in response to mycobacterial infection have been identified in human macrophages either as host defences for bacterial clearance or as pathogen strategies for multiplication and dissemination. These cell death modalities include apoptosis, necrosis, pyroptosis, necroptosis, pyronecrosis, NETosis, and autophagy. These processes are highly overlapping with several mycobacterial proteins participating in more than one cell death pathway. Until now, reviews in M. tb and host cell death have discussed either focusing on host evasion strategies, apoptosis, autophagy, and necrosis or describing all these forms with limited discussions of their role in host-pathogen interactions. Here, we present a comprehensive review of various mycobacterial factors modulating host cell death pathways and the cross-talk between them. Besides this, we have discussed the networking of host cell death pathways including the interference of host miRNA during M. tb infection with their respective targets. Through this review, we present the host targets that overlap across several cell death modalities and the technical limitations of methodology in cell death research. Given the compelling need to discover alternative drug target(s), this review identifies these overlapping cell death factors as potential targets for host-directed therapy.

Dynamic balance of pro- and anti-inflammatory signals controls disease and limits pathology

Immune responses to pathogens are complex and not well understood in many diseases, and this is especially true for infections by persistent pathogens. One mechanism that allows for long-term control of infection while also preventing an over-zealous inflammatory response from causing extensive tissue damage is for the immune system to balance pro- and anti-inflammatory cells and signals. This balance is dynamic and the immune system responds to cues from both host and pathogen, maintaining a steady state across multiple scales through continuous feedback. Identifying the signals, cells, cytokines, and other immune response factors that mediate this balance over time has been difficult using traditional research strategies. Computational modeling studies based on data from traditional systems can identify how this balance contributes to immunity. Here we provide evidence from both experimental and mathematical/computational studies to support the concept of a dynamic balance operating during persistent and other infection scenarios. We focus mainly on tuberculosis, currently the leading cause of death due to infectious disease in the world, and also provide evidence for other infections. A better understanding of the dynamically balanced immune response can help shape treatment strategies that utilize both drugs and host-directed therapies.