Role of cytokines and other factors involved in the Mycobacterium tuberculosis infection

Advances on Electrochemiluminescent Biosensors for TB Biomarkers

Tuberculosis (TB) is a highly contagious bacterial infection that remains a leading cause of death and persistent threat to global health. The spread of TB is exacerbated by the major limitations of conventional diagnostic approaches, such as complex technicalities, high cost, and low sensitivity. To address these challenges, recent research has focused on using electrochemiluminescence (ECL) as an alternative detection strategy coupled to biosensors. ECL biosensors leverage electrochemically generated chemiluminescence, converting electrical energy to light, as a novel transduction mechanism for TB biosensors. This unique approach offers several advantages, namely, wide linear dynamic ranges, improved device sensitivities, and prompt response times for sensitive early detection. This Review offers a comprehensive overview of advancements in ECL biosensor configurations, including detection and amplification strategies, substrates, and the development of luminophores and coreactants tailored for TB biomarker detection. The focus is on ECL biosensor designs, including biorecognition elements like immunosensors, DNA sensors, and aptasensors, along with various immobilization strategies tailored to target specific TB biomarkers. A comprehensive discussion spans biomarker detection trends over the past decade, clinical relevance, sensitivity thresholds, and detection limits. Furthermore, widely recognized TB biomarkers commonly detected in commercial diagnostic tests are discussed alongside novel markers that, while not exclusive to TB, have demonstrated clinical importance. This Review aims to highlight the potential of ECL-based biosensors as an effective means to advance an early, reliable, and accessible TB detection approach.

The Role of Inflammation in the Pathogenesis of Comorbidity of Chronic Obstructive Pulmonary Disease and Pulmonary Tuberculosis

The comorbid course of chronic obstructive pulmonary disease (COPD) and pulmonary tuberculosis is an important medical and social problem. Both diseases, although having different etiologies, have many overlapping relationships that mutually influence their course and prognosis. The aim of the current review is to discuss the role of different immune mechanisms underlying inflammation in COPD and pulmonary tuberculosis. These mechanisms are known to involve both the innate and adaptive immune system, including various cellular and intercellular interactions. There is growing evidence that immune mechanisms involved in the pathogenesis of both COPD and tuberculosis may jointly contribute to the tuberculosis-associated obstructive pulmonary disease (TOPD) phenotype. Several studies have reported prior tuberculosis as a risk factor for COPD. Therefore, the study of the mechanisms that link COPD and tuberculosis is of considerable clinical interest.

Cytokine Dysregulation in pulmonary Tuberculosis: The role of TNF-α/IL-10 and TNF-α/TGF-β ratios as severity indicators

BACKGROUND

In human tuberculosis, Mycobacterium tuberculosis elicits immunopathology characterized by abnormal expression of plasma cytokines. This immunopathology may influence the severity of illness and the efficacy of prolonged anti-mycobacterial treatment.

METHODS

The study analysed TNF-α, IL-10, and TGF-β levels in 90 pulmonary tuberculosis patients and compared them with 90 healthy individuals. The tuberculosis patients were categorized as mild, moderate, or advanced based on chest x-ray results, and the ratio of pro-inflammatory to anti-inflammatory cytokines was compared.

RESULTS

All three cytokines were present in most tuberculosis patients, and their concentrations were noticeably higher than in healthy individuals. The ratio of TNF-α/IL-0 and TNF-α/TGF-β demonstrated the most powerful discriminatory ability in determining the severity of tuberculosis. The levels of TNF-α/IL-0 and TNF-α/TGF-β in individuals with moderate and advanced tuberculosis were markedly elevated compared to those with mild cases. The area under the curve (AUC) for TNF-α/TGF-β and TNF-α/IL-0 was determined to be 0.823 and 0.814, respectively.

CONCLUSIONS

The elevated ratio of TNF-α/IL-0 and TNF-α/TGF-β in the sera of TB patients may contribute to an excessive pro-inflammatory response, whereas a lower ratio may regulate excessive inflammation. Both the TNF-α/IL-0 and TNF-α/TGF-β ratios may effectively categorize the tuberculosis severity and have the potential to serve as biomarkers for evaluating the early response to treatment.

CD14++CD16- classical monocyte subset secreting IL-1ß and IL-10 is associated with 'Tuberculosis Resisters' phenotype

Mycobacterium tuberculosis (M.tb) infection can lead to various outcomes, including active tuberculosis or latent tuberculosis infection (LTBI). Household contacts of TB cases have a high risk of acquiring LTBI. However, some contacts exposed to M.tb remain negative for tuberculin skin test (TST) and interferon-gamma release assay (IGRA) tests and are called 'TB resisters'. Characterization of immune responses in 'TB resisters' may help to understand correlates of protection against M.tb. Based on the TST and IGRA tests, household contacts were divided into 'LTBI' and 'TB Resisters'. Peripheral blood mononuclear cells (PBMCs) of the study participants were isolated and processed to characterize the monocyte subsets based on CD14 and CD16 expression in flow cytometry. Monocyte intracellular cytokine expression (IL-10, IL-6, TNF-α and IL-1ß) was assessed after Lipopolysaccharide (LPS) stimulation. LTBI and active TB patients showed a higher frequency of intermediate and non-classical monocyte subsets depicting the infectious stage. Higher frequency of classical monocyte subsets was associated with 'TB resisters'. Marked expression of IL-1ß and a higher monocyte to lymphocytes (M/L) ratio was seen in PTB, LTBI and TB resister groups compared to healthy controls indicating active disease or exposure to M.tb. Classical Monocytes (CM) were further found to be associated with higher expression of IL-1ß and IL-10 in the 'TB resister group', which might help in the clearance of infection at an early stage. LTBI and PTB showed significantly higher TNF-α producing monocytes than healthy controls and 'TB Resisters'. IL6-producing monocytes were significantly higher in LTBI compared to other study groups. These findings could further be explored with follow-up in cohort of 'TB resisters'. Also, the role of IL-1ß and IL10 secreting classical monocytes in early clearance of infection could be explored with in vitro mechanistic studies.

Immunological mechanisms involved in the protection against development of pulmonary tuberculosis in naturally infected goats

Tuberculosis (TB) is a notifiable zoonotic disease caused by bacteria of the Mycobacterium tuberculosis complex (MTBC) that affects a multitude of domestic and wild species. The main lesions caused by these mycobacteria are tuberculous granulomas, which determine the organism's immune response to the disease. Although TB pathogenesis in cattle has been extensively studied, information regarding its progression in other species of interest for the maintenance and transmission of TB such as goats remains limited. This study aimed to characterise the immune response developed in the lungs of goats naturally infected with mycobacteria of MTBC by assessing key cell populations and immunomodulatory molecules involved in defending against TB. Hence, twelve 6-12-month-old Guadarrama kid goats, initially TB-free, were selected and exposed to M. bovis through close contact with other infected goats. Only animals that tested positive by any of the TB diagnostic methods at the end of the experiment were included in the final analysis (n = 9). Gross and microscopic lesions compatible with TB (TBL) in different organs, as well as local response to TB in lungs were evaluated. Our results revealed that after five months of exposure, 44.4 % (4/9) of the M. bovis-infected animals exhibited TBL in the lungs (TBLL+), characterized by a predominance of non-cavitary necrotic granulomas. TBLL+ animals showed significantly higher presence of neutrophils, macrophages (MΦs) and lymphocytes along with greater expression of interferon (IFN)-γ. Conversely, the remaining animals did not present macroscopic or microscopic TBL in the lungs (TBLL-) (5/9). However, these goats displayed elevated expression of toll-like receptors (TLR)2 and TLR4 alongside heightened expression of pro-inflammatory cytokines, inducible nitric oxide synthase (iNOS) and interleukin (IL)-10. These results suggest the potential development of an effective immune response that may suppress or delay of TBL in infected animals. Further research is needed to elucidate how these molecules, which are involved in the defence against MTBC, confer protection and modulate their expression during infection for TB control.

Deciphering the Correlation between the Emergence of Lung Carcinoma Associated with Tuberculosis-related Inflammation

Lung cancer and tuberculosis (TB) are classified as the second-most life-threatening diseases globally. They both are exclusively represented as major public health risks and might exhibit similar symptoms, occasionally diagnosed simultaneously. Several epidemiological studies suggest that TB is a significant risk factor for the progression of lung cancer. The staggering mortality rates of pulmonary disorders are intrinsically connected to lung cancer and TB. Numerous factors play a pivotal role in the development of TB and may promote lung carcinogenesis, particularly among the geriatric population. Understanding the intricacies involved in the association between lung carcinogenesis and TB has become a crucial demand of current research. Consequently, this study aims to comprehensively review current knowledge on the relationship between tuberculosis-related inflammation and the emergence of lung carcinoma, highlighting the impact of persistent inflammation on lung tissue, immune modulation, fibrosis, aspects of reactive oxygen species, and an altered microenvironment that are linked to the progression of tuberculosis and subsequently trigger lung carcinoma.

Intestinal Helminth Infections and Their Association with QuantiFERON-TB Gold Plus Test Performance in an Endemic Setting, Northwest Ethiopia

Background

Timely detection and treatment of latent TB infection (LTBI) is part of WHO's strategy against tuberculosis (TB). Helminth infections can modulate immune responses, potentially impacting the performance of interferon-gamma release assays (IGRAs) such as the QuantiFERON-TB Gold Plus (QFT-Plus). This study evaluated the association between helminth infections and QFT-Plus results among participants from a TB-endemic region.

Methods

A cross-sectional study was conducted from October 2022 to March 2023 in Bahir Dar, Ethiopia. Stool samples of 314 potential participants were examined for helminths using wet mount and Kato-Katz techniques. LTBI was assessed by QFT-Plus from a total of 100 gender-matched helminth-positive and -negative participants. The association between helminth infection status, egg count, and QFT-Plus positivity was analyzed, and p values <0.05 were considered significant.

Results

Overall, 53 of 314 screened participants were infected with helminths (16.9%), with A. lumbricoides (47.2%) and hookworm (30.2%) as most prevalent species. The overall QFT-Plus positivity rate was 30.0%, with similar rates observed between helminth-positive and helminth-negative participants. Although QFT-Plus positivity was slightly lower in hookworm carriers (25%) compared to those with A. lumbricoides (32%), a higher-than-median hookworm egg burden was significantly associated with reduced QFT-Plus positivity (P = 0.029). QFT-Plus positivity was significantly higher among male participants than females (P = 0.032).

Conclusion

While overall helminth infection status did not significantly affect QFT-Plus positivity, higher hookworm burden was associated with reduced QFT-Plus reactivity. These findings suggest that the type of helminth and infection intensity, rather than its mere presence, may influence IGRA performance. Further studies with larger sample sizes are warranted to understand the species-specific effect of helminth infection on immune modulation of the host.

Immune profiles of MCP-1 with M tb antigens and recombinant cytokines stimulation in tuberculosis

Tuberculosis is caused by Mycobacterium tuberculosis (M tb), which is recognized by macrophages and produces inflammatory cytokines, and chemokines at the site of infection. The present study was proposed to understand the interaction of M tb antigens, cytokines, and chemokines. We have evaluated the chemokine MCP-1 levels and its expression in PBMCs stimulated with M tb antigens Ag85A, ESAT6 and recombinant cytokines rhTNF-α, rhIFN-γ, rhTGF-β, and rhIL-10 in active pulmonary TB (APTB) patients, household contacts (HHC) at 0 months, 6 months and healthy controls (HC). We have observed low levels of MCP-1 with Ag85A, ESAT6, and rhTNF-α stimulations in APTB 0M compared to HHC and HC (p < 0.0067, p < 0.0001, p < 0.01, p < 0.005, p < 0.0065, p < 0.0001) and significantly increased after treatment with rhTNF-α. The MCP-1 levels with rhIFN-γ were high in APTB, HHC at 0 M and significant between APTB 0 M vs. 6 M, HHC vs. HC, and HHC 0M vs. 6M (p < 0.0352, p < 0.0252, p < 0.00062). The rhTGF-β, rhIL-10 induced high MCP-1 levels in APTB, HHC compared to HC (p < 0.0414, p < 0.0312, p < 0.004, p < 0.0001) and significantly decreased after treatment with rhIL-10 (p < 0.0001). The MCP-1 expression was low with all the stimulations in APTB 0M when compared to HC and after treatment. Whereas, HHC shown low MCP-1 expression with rhTNF-α, rhIFN-γ and Ag85A and high with rhTGF-β, rhIL-10 and ESAT6. In conclusion, the study determined the differential expression and production of MCP-1 with M tb antigens and recombinant cytokines. Further, cohort studies are required to study these interaction to identify the high risk individuals, which might help for TB control.

An Immunoinformatics-Based Study of Mycobacterium tuberculosis Region of Difference-2 Uncharacterized Protein (Rv1987) as a Potential Subunit Vaccine Candidate for Preliminary Ex Vivo Analysis

Mycobacterium tuberculosis (Mtb) is the pathogen that causes tuberculosis and develops resistance to many of the existing drugs. The sole licensed TB vaccine, BCG, is unable to provide a comprehensive defense. So, it is crucial to maintain the immunological response to eliminate tuberculosis. Our previous in silico study reported five uncharacterized proteins as potential vaccine antigens. In this article, we considered the uncharacterized Mtb H37Rv regions of difference (RD-2) Rv1987 protein as a promising vaccine candidate. The vaccine quality of the protein was analyzed using reverse vaccinology and immunoinformatics-based quality-checking parameters followed by an ex vivo preliminary investigation. In silico analysis of Rv1987 protein predicted it as surface localized, secretory, single helix, antigenic, non-allergenic, and non-homologous to the host protein. Immunoinformatics analysis of Rv1987 by CD4 + and CD8 + T-cells via MHC-I and MHC-II binding affinity and presence of B-cell epitope predicted its immunogenicity. The docked complex analysis of the 3D model structure of the protein with immune cell receptor TLR-4 revealed the protein's capability for potential interaction. Furthermore, the target protein-encoded gene Rv1987 was cloned, over-expressed, purified, and analyzed by mass spectrometry (MS) to report the target peptides. The qRT-PCR gene expression analysis shows that it is capable of activating macrophages and significantly increasing the production of a number of key cytokines (TNF-α, IL-1β, and IL-10). Our in-silico analysis and ex vivo preliminary investigations revealed the immunogenic potential of the target protein. These findings suggest that the Rv1987 be undertaken as a potent subunit vaccine antigen and that further animal model immuno-modulation studies would boost the novel TB vaccine discovery and/or BCG vaccine supplement pipeline.

Transforming growth factor-β, Interleukin-23 and interleukin-1β modulate TH22 response during active multidrug-resistant tuberculosis

We previously reported that patients with multidrug-resistant tuberculosis (MDR-TB) showed low systemic and Mtb-induced Th22 responses associated to high sputum bacillary load and severe lung lesions suggesting that Th22 response could influence the ability of these patients to control bacillary growth and tissue damage. In MDR-TB patients, the percentage of IL-22+ cells inversely correlates with the proportion of senescent PD-1+ T cells. Herein, we aimed to evaluate the pathways involved on the regulation of systemic and Mtb-induced Th22 response in MDR-TB and fully drug-susceptible TB patients (S-TB) and healthy donors. Our results show that while IL-1β and IL-23 promote Mtb-induced IL-22 secretion and expansion of IL-22+ cells, TGF-β inhibits this response. Systemic and in vitro Mtb-induced Th22 response inversely correlates with TGF-β amounts in plasma and in PBMC cultures respectively. The number of circulating PD-1+ T cells directly correlates with plasmatic TGF-β levels and blockade of PD-1/PD-L1 signalling enhances in vitro Mtb-induced expansion of IL-22+ cells. Thus, TGF-β could also inhibit Th22 response through upregulation of PD-1 expression in T cells. Higher percentage of IL-23+ monocytes was observed in TB patients. In contrast, the proportion of IL-1β+ monocytes was lower in TB patients with bilateral lung cavities (BCC) compared to those patients with unilateral cavities (UCC). Interestingly, TB patients with BCC showed higher plasmatic and Mtb-induced TGF-β secretion than patients with UCC. Thus, high TGF-β secretion and subtle differences in IL-23 and IL-1β expression could diminish systemic and in vitro Mtb-induced Th22 response along disease progression in TB patients.

Tuberculous Lymphadenitis in a Patient Treated with Dupilumab: A Case Report

Tuberculous lymphadenitis is among the most frequent presentations of extrapulmonary tuberculosis; the most common presentation is isolated chronic non-tender lymphadenopathy in young adults without systemic symptoms. Dupilumab is a fully human monoclonal antibody directed against interleukin-4 receptor-α that blocks the synergistic effects of interleukin-4 and interleukin-13 on allergic inflammation. Its well-known adverse events are allergic conjunctivitis, injection site reaction, and dupilumab facial redness. A 32-year-old female with severe atopic dermatitis was treated with dupilumab for 2 months at our clinic. She complained of multiple enlarged palpable lymph nodes on the right side of the neck and inguinal area for 2 months. Laboratory tests showed an increased total eosinophil count and immunoglobulin E level, as well as positive interferon-γ release assays. Radiological examination showed multiple low echoic and heterogeneous well-enhancing lymph nodes in level II, III, IV, and V of the neck. Histological examination revealed caseous necrosis and tuberculoid granuloma. The lymph node enlargements were completely relieved after antituberculosis treatment. The mechanism for the development of tuberculous lymphadenitis in a patient receiving dupilumab is not fully understood yet. In some previous studies, treatment with dupilumab suppressed the expression of genes related not only to T helper 2 and eosinophil response but also to proinflammatory responses. It could not inhibit the intracellular growth of Mycobacterium tuberculosis in macrophages, predisposing them to the development of tuberculous infection. To the best of our knowledge, this is the first report on the development of tuberculosis lymphadenitis in a patient treated with dupilumab.

Association of Cytokine Gene Polymorphisms and Their Impact on Active and Latent Tuberculosis in Brazil's Amazon Region

Some genetic variations in cytokine genes can alter their expression and influence the evolution of Mycobacterium tuberculosis (Mtb) infection. This study aimed to investigate the association of polymorphisms in cytokine genes and variability in plasma levels of cytokines with the development of tuberculosis (TB) and latent tuberculosis infection (LTBI). Blood samples from 245 patients with TB, 80 with LTBI, and healthy controls (n = 100) were included. Genotyping of the IFNG +874A/T, IL6 -174G/C, IL4 -590C/T, and IL10 -1082A/G polymorphisms was performed by real-time PCR, and cytokine levels were determined by flow cytometry. Higher frequencies of genotypes AA (IFNG +874A/T), GG (IL6 -174G/C), TT (IL4 -590C/T), and GG (IL10 -1082A/G) were associated with an increased risk of TB compared to that of LTBI (p = 0.0027; p = 0.0557; p = 0.0286; p = 0.0361, respectively) and the control (p = <0.0001, p = 0.0021; p = 0.01655; p = 0.0132, respectively). In combination, the A allele for IFNG +874A/T and the T allele for IL4 -590C/T were associated with a higher chance of TB (p = 0.0080; OR = 2.753 and p < 0.0001; OR = 3.273, respectively). The TB group had lower levels of IFN-γ and higher concentrations of IL-6, IL-4, and IL-10. Cytokine levels were different between the genotypes based on the polymorphisms investigated (p < 0.05). The genotype and wild-type allele for IFNG +874A/T and the genotype and polymorphic allele for IL4 -590C/T appear to be more relevant in the context of Mtb infection, which has been associated with the development of TB among individuals infected by the bacillus and with susceptibility to active infection but not with susceptibility to latent infection.

Cytokine upsurge among drug-resistant tuberculosis endorse the signatures of hyper inflammation and disease severity

Tuberculosis (TB) elimination is possible with the discovery of accurate biomarkers that define the stages of infection. Drug-resistant TB impair the current treatment strategies and worsen the unfavourable outcomes. The knowledge on host immune responses between drug-sensitive and drug-resistant infection is inadequate to understand the pathophysiological differences and disease severity. The secreted proteins, cytokines display versatile behaviour upon infection with Mycobacterium tuberculosis (MTB) and their imbalances often tend to assist disease pathology than protection. Therefore, studying these soluble proteins across TB infection spectrum (drug-resistant TB, drug-sensitive TB, and latent TB) may unveil the disease mediated responses and unique stage specific cytokine signatures. Thus, we sought to determine the plasma cytokine levels from healthy, latently infected, drug-sensitive, and drug-resistant TB individuals. Our study revealed top 8 cytokines (IL-17, IL-1α, IL-2, IL-10, IL-5, IFN-γ, TNF-α and IL-6) and their biomarker abilities to discriminate different stages of infection.

Immunological Interactions between Intestinal Helminth Infections and Tuberculosis

Helminth infections are among the neglected tropical diseases affecting billions of people globally, predominantly in developing countries. Helminths’ effects are augmented by coincident tuberculosis disease, which infects a third of the world’s population. The role of helminth infections on the pathogenesis and pathology of active tuberculosis (T.B.) remains controversial. Parasite-induced suppression of the efficacy of Bacille Calmette-Guerin (BCG) has been widely reported in helminth-endemic areas worldwide. T.B. immune response is predominantly proinflammatory T-helper type 1 (Th1)-dependent. On the other hand, helminth infections induce an opposing anti-inflammatory Th2 and Th3 immune-regulatory response. This review summarizes the literature focusing on host immune response profiles during single-helminth, T.B. and dual infections. It also aims to necessitate investigations into the complexity of immunity in helminth/T.B. coinfected patients since the research data are limited and contradictory. Helminths overlap geographically with T.B., particularly in Sub-Saharan Africa. Each disease elicits a response which may skew the immune responses. However, these effects are helminth species-dependent, where some parasites have no impact on the immune responses to concurrent T.B. The implications for the complex immunological interactions that occur during coinfection are highlighted to inform government treatment policies and encourage the development of high-efficacy T.B. vaccines in areas where helminths are prevalent.

Interleukin-37 gene polymorphism and susceptibility to pulmonary tuberculosis among Iraqi patients

BACKGROUND

Control of tuberculosis (TB) depends on a balance between host's immune factors and bacterial evasion strategies. Interleukin-37 (IL-37) is among the immunomodulatory factors that have been proposed to influence susceptibility to tuberculosis.

METHODS

A case-control study was conducted on 105 patients with pulmonary TB (37 active, 41 multi-drug resistant and 27 relapse) and 79 healthy controls to determine serum levels and single nucleotide polymorphisms (SNPs) of IL-37. The IL-37 level was assessed with an enzyme-linked immunosorbent kit, while DNA-sequencing was used to detect SNPs in the promoter region of IL37 gene.

RESULTS

Median level of IL-37 was markedly increased in serum of TB patients compared to controls (325.0 vs. 169.1 pg/mL; p < 0.001). This increase was universally determined in subgroups of patients distributed according to gender, age groups, and clinical type of disease, while no significant differences were found between the subgroups in patients or controls. Analysis of receiver operating characteristic curve confirmed these findings and IL-37 occupied a very good area under the curve, which was 0.816 (95% CI = 0.744-0.888; p < 0.001). At a cut-off value of 185.6 pg/mL, the sensitivity and specificity of IL-37 were 81.0 and 82.3%, respectively. Of the nine detected SNPs (rs2466449 G/A, rs2466450 A/G, rs2723168 G/A, rs3811042 G/A, rs3811045 T/C, rs3811046 G/T, rs3811047 A/G, rs3811048 G/A and rs200782323 G/A), only rs3811048 showed a significant association with TB; the G allele showed a significantly decreased frequency in TB patients compared to controls (25.2 vs. 44.9%; OR = 0.41; p < 0.001). It was possible to assign five haplotypes, and three showed significant differences between patients and controls. Frequency of haplotype A-A-G-A-C-T-G-A-G (0.331 vs. 0.213; OR = 2.10; p = 0.015) was significantly increased in TB patients compared to controls. On the contrary, frequencies of haplotypes A-A-G-A-C-T-G-G-G (0.029 vs. 0.116; OR = 0.24; p = 0.01) and A-A-G-G-T-G-A-G-G (0.140 vs. 0.275; OR = 0.45; p = 0.015) were significantly decreased in patients.

CONCLUSIONS

IL-37 was up-regulated in the serum of TB patients irrespective of their gender, age or clinical type of disease. SNPs in the promoter region of IL37 gene were proposed to be associated with susceptibility to TB.

Designing of a Chimeric Vaccine Using EIS (Rv2416c) Protein Against Mycobacterium tuberculosis H37Rv: an Immunoinformatics Approach

Mycobacterium tuberculosis (Mtb) is a respiratory pathogen that causes tuberculosis (TB). There are a large number of proteins that are involved in the pathogenesis of TB. Stimulating the immune response against TB is very important to clear the pathogens from host. In the present study, an immunoinformatics conduit is used for designing an epitope based chimeric vaccine against TB. Enhanced intracellular survival (EIS) protein from Mtb is used for designing the chimeric vaccine. One B cell epitope, 8 cytotoxic T lymphocyte (CTL), and 6 helper T lymphocyte (HTL) epitopes were predicted based on the MHC allele binding, immunogenicity, antigenicity, allergenicity, toxicity and IFN epitopes. The selected epitopes were used for chimeric vaccine designing. Furthermore, 3D structure elucidation, structural refinement and validation of the designed chimeric vaccine were carried out. The 3D structure was used for protein-protein docking studies with Toll-like receptor 4 (TLR-4), followed by molecular dynamic simulation (MDS) and the interaction between the chimeric vaccine and TLR-4 complex was verified.

ESAT-6 impedes IL-18 mediated phagosome lysosome fusion via microRNA-30a upon Calcimycin treatment in mycobacteria infected macrophages

The weaponry possessed by Mycobacterium tuberculosis (M. tb) in the form of immunodominant antigens hijack the host immune system to give a survival advantage to this intracellular fiend, but the mechanism of this control is not entirely known. Since we have previously reported the mechanism of autophagy inhibition by early secreted antigenic target 6 kDa (ESAT-6) through microRNA (miR)-30a-3p in Calcimycin treated differentiated THP-1 (dTHP-1) cells, the present study was undertaken to deduce the effect of miR-30a on the immunomodulatory profile of ESAT-6 treated cells and the mechanism involved thereof, if any. Initially, the effect of recombinant ESAT-6 (rESAT-6) on the immunomodulatory profile in Calcimycin-treated phorbol 12-myristate 13-acetate (PMA) dTHP-1 cells was checked. Later, transfection studies using miR-30a-3p inhibitor or -5p mimic highlighted the contrary roles of different arms of the same miRNA in regulating IL-18 response by ESAT-6 in dTHP-1 cells after Calcimycin treatment. By using either IL-18 neutralizing antibody or inhibitors of phosphoinositide 3-kinase (PI3K)/NF-κB/phagosome-lysosome fusion in the miRNA-30a transfected background, IL-18 mediated signaling and intracellular killing of mycobacteria was reversed in the presence of ESAT-6. Overall, the results of this study conclusively prove the contrary roles of miR-30a-3p and miR-30a-5p in regulating IL-18 signaling by ESAT-6 in dTHP-1 cells upon Calcimycin treatment that affected phagosome-lysosome fusion and intracellular survival of mycobacteria.

Multidrug-Resistant Pseudomonas aeruginosa Triggers Differential Inflammatory Response in Patients With Endophthalmitis

Purpose

Infections with multidrug-resistant Pseudomonas aeruginosa (MDR-PA) lead to poor clinical outcomes in endophthalmitis patients, and its interactions with the host immune system remain largely unknown. The current study aimed to determine the association of MDR-PA infection with the cytokine expression profile in patients with endophthalmitis.

Methods

Vitreous of 12 patients with culture-proven MDR-PA along with 12 samples from antibiotic-susceptible P. aeruginosa (S-PA) and 20 non-infectious controls were included in the study. Expression patterns of IL-6, IL-10, IL-1α, IL-1β, IFN-γ, TNF-α, IL-8, and GM-CSF in the vitreous were analyzed by multiplex immunoassay and correlated with the clinical severity. We also assessed the phosphorylation level of different immune pathway molecules.

Results

In the MDR-PA group, significantly (P < 0.05) increased expression of IL-6, IL-8, IL-10, IL-1β, and TNF-α was observed in comparison with the S-PA group. The increased inflammatory mediators in MDR-PA correlated with the disease severity. Additionally, the increased expression of inflammatory mediators was positively correlated to the activation levels of Akt, STAT3, JNK, p70 S6 kinase, and NF-кB (P < 0.05) in the MDR-PA group.

Conclusions

The current study shows the differential host immune response and phosphorylation levels of signaling molecules in MDR-PA endophthalmitis, thereby linking antibiotic resistance with distinct immune regulation.

Translational Relevance

This study provides evidence for the use of inflammatory mediator levels of IL-6, IL-8, IL-10, IL-1β, and TNF-α as potential diagnostic biomarkers of MDR endophthalmitis warranting prompt administration of immune modulators to avoid irreversible damage to the retina and vision loss.

Beneficial effect of long-chain n-3 polyunsaturated fatty acid supplementation on tuberculosis in mice

Intakes of the omega-3 essential fatty acids (n-3 EFAs) are low in the general adult population, with high n-6/n-3 polyunsaturated fatty acid (PUFA) ratios and the accompanying suboptimal n-3 PUFA status. Eicosapentaenoic (EPA) and docosahexaenoic acid (DHA) have antibacterial and inflammation-resolving effects in tuberculosis (TB). However, whether switching to a diet with optimum n-3 EFA intake after the infection has comparable benefits has not been investigated. We aimed to compare the effects of a diet with sufficient n-3 EFA content in an acceptable n-6/n-3 PUFA ratio for rodents ((n-3)eFAS group) with those on the same diet supplemented with EPA and DHA (EPA/DHA group) in Mycobacterium tuberculosis (Mtb)-infected C3HeB/FeJ mice with a low n-3 PUFA status. Mice were conditioned on an n-3 PUFA-deficient diet with a high n-6/n-3 PUFA ratio for 6 weeks before Mtb infection and randomized to either (n-3)eFAS or EPA/DHA diets 1 week post-infection for 3 weeks. At endpoint, EPA and DHA compositions were higher and arachidonic acid, osbond acid, and total n-6 LCPUFAs lower in all lipid pools measured in the EPA/DHA group (all P < 0.001). Percentage body weight gain was higher (P = 0.017) and lung bacterial load lower (P < 0.001) in the EPA/DHA group. Additionally, the EPA/DHA group had a more pro-resolving lung lipid mediator profile and lower lung in IL-1α and IL-1β concentrations (P = 0.023, P = 0.049). Inverse correlations were found between the lung and peripheral blood mononuclear cell EPA and DHA and selected pro-inflammatory cytokines. These are the first findings that indicate that EPA/DHA supplementation provides benefits superior to a diet with sufficient n-3 EFAs concerning bacterial killing, weight gain and lung inflammation resolution in Mtb-infected mice with a low n-3 PUFA status. Therefore, EPA and DHA may be worth considering as adjunct TB treatment.

Influence of NOD-like receptor 2 gene polymorphisms on muramyl dipeptide induced pro-inflammatory response in patients with active pulmonary tuberculosis and household contacts

PURPOSE

The immune response induced by nucleotide-binding oligomerization domain-2(NOD2) is associated with the production of cytokines affected by the host's genetic background. The present study aimed to examine the effects of NOD2; 802C > T, 2105G > A polymorphisms associated with altered cytokine levels in patients with active pulmonary tuberculosis disease, Latent TB subjects (household contacts(HHC) and healthy controls(HC).

METHODS

Genetic polymorphisms were analyzed by Restriction Fragment Length Polymorphism(RFLP) in 102-PTB patients, 102-HHC, and 132-HC. QuantiFERON-TB Gold In-Tube test was performed to identify latent TB infection in 60-HHC. Estimated their cytokine levels by ELISA in MDP (muramyl dipeptide) stimulated culture supernatants of all the groups. Further, we studied pre-mRNA structures by insilico analysis and relative gene expression by RT-PCR.

RESULTS

Recessive genetic models of NOD2 802C > T SNP with TT genotype and AA genotype of NOD2 2105G > A SNP were significantly associated with increased TB risk in PTB patients and HHC compared with HC. In vitro stimulations were performed with NOD2 ligand MDP in PTB patients and latent TB subjects: QuantiFERON positive household contacts (QFT + ve HHC)and QuantiFERON negative household contacts(QFT-ve HHC). The results showed that reduced TNF-α and enhanced IL-12, IL-1β indicate that these cytokines may play an essential role in the initial maintenance of cell-mediated immunity. Our study demonstrated the correlation between NOD2 polymorphism with IL-1β, TNF-α, IL-12 levels. Insilico analysis represents the pre-mRNA secondary structures affected by NOD2 SNPs. We also observed the difference in m RNA levels in variant and wild genotypes.

CONCLUSION

This finding may lead to the forthcoming development of immunotherapy and may be used as predictive markers to identify high-risk individuals for TB disease.

Reduced tissue colonization of Mycobacterium avium subsp. paratuberculosis in neonatal calves vaccinated with a cocktail of recombinant proteins

An increasing prevalence of paratuberculosis supports the need for new efficacious vaccines as an essential management tool. Two separate studies were performed in neonatal calves to evaluate the effectiveness of pooled recombinant Mycobacterium avium subsp. paratuberculosis (MAP) proteins (MAP1087, MAP1204, MAP1272c, MAP2077c) as a potential vaccine. In the first study vaccinated calves were immunized with 400 µg protein cocktail per dose, whereas the second study compared doses of 400 µg and 800 µg of protein cocktail, followed by challenge with live MAP for both vaccinated and nonvaccinated control calves 28 days post-vaccination. At the end of 12 months, tissue colonization with MAP was significantly reduced for the vaccinated calves compared to control animals. A higher dose of vaccine improved protection, with further reductions of MAP burden. Antigen-specific IFN-γ responses and serum antibody responses were similar regardless of vaccination, indicating exposure to MAP invoked conventional host immune responses. Host immunity differed due to vaccination, resulting in increased percentages of CD4+ T cells and B cells after stimulation of PBMCs with antigen. Interestingly, gene expression in PBMCs was similar for both control and vaccinated calves except for significant increases in IFN-γ, IL-12, and IL-17 expression observed in vaccinated calves. Vaccination with a cocktail of immunogenic recombinant MAP proteins was efficacious in reducing the level of infection and fecal shedding of neonatal calves and may be a potential tool for curtailing the spread of Johne's disease.

Significance of the chemokine CXCL10 and human beta-defensin-3 as biomarkers of pulmonary tuberculosis

The biomarker significance of IL-35, chemokines (CXCL9 and CXCL10) and human beta-defensins (hBD2 and hBD3) was determined in pulmonary tuberculosis (TB) of 105 Iraqi patients; 37 had active disease, 41 had multi-drug resistant (MDR) PTB and 27 had a relapse of TB. A control sample of 79 healthy persons was also included. Serum levels of markers were assessed using enzyme-linked immunosorbent assay kits. Kruskal-Wallis test together with Dunn-Bonferroni post hoc test revealed significance differences between patients and controls in levels of IL-35, CXCL9, CXCL10 and hBD3, while hBD2 showed no significant difference. Receiver operating characteristic analysis demonstrated that CXCL10 and hBD3 were the most significant markers in predicting TB, particularly active disease. Logistic regression analysis proposed the susceptibility role of CXCL10 in TB. Gender- and age-dependent variations were also observed. Spearman's rank correlation analysis showed different correlations between markers in each group of patients and controls. In conclusion, CXCL10 was up-regulated in serum of TB patients, while hBD3 showed down-regulated level. Both serum proteins are possible candidate biomarkers for evaluation of TB progression, particularly in active disease.

The M. tuberculosis Rv1523 Methyltransferase Promotes Drug Resistance Through Methylation-Mediated Cell Wall Remodeling and Modulates Macrophages Immune Responses

The acquisition of antibiotics resistance is a major clinical challenge limiting the effective prevention and treatment of the deadliest human infectious disease tuberculosis. The molecular mechanisms by which initially Mycobacterium tuberculosis (M.tb) develop drug resistance remain poorly understood. In this study, we report the novel role of M.tb Rv1523 MTase in the methylation of mycobacterial cell envelope lipids and possible mechanism of its contribution in the virulence and drug resistance. Initial interactome analyses predicted association of Rv1523 with proteins related to fatty acid biosynthetic pathways. This promoted us to investigate methylation activity of Rv1523 using cell wall fatty acids or lipids as a substrate. Rv1523 catalyzed the transfer of methyl group from SAM to the cell wall components of mycobacterium. To investigate further the in vivo methylating role of Rv1523, we generated a recombinant Mycobacterium smegmatis strain that expressed the Rv1523 gene. The M. smegmatis strain expressing Rv1523 exhibited altered cell wall lipid composition, leading to an increased survival under surface stress, acidic condition and resistance to antibiotics. Macrophages infected with recombinant M. smegmatis induced necrotic cell death and modulated the host immune responses. In summary, these findings reveal a hitherto unknown role of Rv1523 encoded MTase in cell wall remodeling and modulation of immune responses. Functional gain of mycolic acid Rv1523 methyltransferase induced virulence and resistance to antibiotics in M. smegmatis. Thus, mycolic acid methyltransferase may serve as an excellent target for the discovery and development of novel anti-TB agents.

Analysis of IFN-gamma and IL-10 Levels as Markers of Inflammation and Response Therapy of Anti-Tuberculosis in MDR Lung TB Patients

Multidrug-Resistant Tuberculosis (MDR TB) is caused by an organism that is resistant to at least isoniazid and rifampisin, the two most potent TB drug. Immune response to against Mycobacterum tuberculosis infection is related to the function of immunity. The function of interferon-γ (pro-inflammatory) is to activate macrophages, to stimulate antimicrobial molecules (to reactive oxygen species and nitric oxide), and to inhibits interleukin-10. Interleukin-10 function is to triggers humoral immunity, to inhibit IFN- γ. This study aimed to analyze level changes and the correlation with clinical data, also months of MDR TB patients who received standard OAT therapy. This was an observational study using cross sectional design. There were 29 patients who received standard MDR TB OAT therapy from 1-24 months, who met the inclusion criteria. Then, the patients were divided based on duration of the therapy, which are the initial/intensive and advanced phase. The initial phase divided into 2: first one is for 1-4 months therapy’s time (5 patients) and the second one is for more than 4-8 months (6 patients). Then, the advanced group divided into two groups again, which are third group with more than 8-16 months (13 patients) and fouth group with more than 16-24 months (5 patients). Then, measured serum concentration IFN-γ, IL-10 at the start of the study and 4 weeks later with the ELISA method. This research during the period July-December (6 months). IFN-γ post concentrations were decreased by 39.14 ± 139.12 pg/mL (p > 0.05). The concentration of IL-10 was decreased by 33.93 ± 109.20pg/mL (p>0.05). Based on the TB score bandim method during pre and posts results were 1 patient experienced severity change from severity class 1 to 2, 1 patient from severity class 2 to 1, 1 patient remained in severity 2 and 26 patient remained in severity 1. The results showed that serum IFN-γ and IL-10 levels in initial/intensive and advanced phase patients who received MDR TB regiment after four weeks did not changed,

Human gene expression profiling identifies key therapeutic targets in tuberculosis infection: A systematic network meta-analysis

Tuberculosis (TB) is one of the deadliest diseases since ancient times and is still a global health problem. So, there is a need to develop new approaches for early detection of TB and understand the host-pathogen relationship. In the present study, we have analyzed microarray data sets and compared the transcriptome profiling of the healthy individual with latent infection (LTBI) and active TB (TB) patients, and identified the differentially expressed genes (DEGs). Next, we performed the systematic network meta-analysis of the DEGs, which identified the seven most influencing hub genes (IL6, IL1B, TNF, NFKB1, STAT1, JAK2, and MAPK8) as the potential therapeutic target in the tuberculosis disease. These target genes are involved in many biological processes like cell cycle control, apoptosis, complement signalling, enhanced cytokine & chemokine signalling, pro-inflammatory responses, and host immune responses. Additionally, we also identified 22 inferred genes that are mainly engaged in the induction of innate immune response, cellular response to interleukin-6, inflammatory response, apoptotic process, I-kappaB-phosphorylation, JAK-STAT signalling pathway, macrophage activation, cell growth, and cell signalling. The proper attention of these inferred genes may open up a new horizon to understand the defensive mechanisms of TB disease. The transcriptome profiling and network approach can enhance the understanding of the molecular pathogenesis of tuberculosis infection and have implications for the plan and execution of mRNA expression tools to support early diagnostics and treatment of Mycobacterium tuberculosis (M.tb).

Mycobacterium tuberculosis-specific cytokine biomarkers to differentiate active TB and LTBI: A systematic review

OBJECTIVES

New tests are needed to overcome the limitations of existing immunodiagnostic tests for tuberculosis (TB) infection, including their inability to differentiate between active TB and latent TB infection (LTBI). This review aimed to identify the most promising cytokine biomarkers for use as stage-specific markers of TB infection.

METHODS

A systematic review was done using electronic databases to identify studies that have investigated Mycobacterium tuberculosis (MTB)-specific cytokine responses as diagnostic tools to differentiate between LTBI and active TB.

RESULTS

The 56 studies included in this systematic review measured the MTB-specific responses of 100 cytokines, the most frequently studied of which were IFN-γ, IL-2, TNF-α, IP-10, IL-10 and IL-13. Ten studies assessed combinations of cytokines, most commonly IL-2 and IFN-γ. For most cytokines, findings were heterogenous between studies. The variation in results likely relates to differences in the study design and laboratory methods, as well as participant and environmental factors.

CONCLUSIONS

Although several cytokines show promise as stage-specific markers of TB infection, this review highlights the need for further well-designed studies, in both adult and paediatric populations, to establish which cytokine(s) will be of most use in a new generation of immunodiagnostic tests.

Determination of in vitro and in vivo immune response to recombinant cholesterol oxidase from Mycobacterium tuberculosis

Cholesterol oxidase (ChoD) is an enzyme that is involved but is dispensable in the process of cholesterol degradation by Mycobacterium tuberculosis (Mtb). Interestingly, ChoD is a virulence factor of Mtb, and it strongly modulates the function of human macrophages in vitro, allowing the intracellular survival of bacteria. Here, we determined the immunogenic activity of recombinant ChoD from Mtb in a mouse model. We found that peritoneal exudate cells obtained from mice injected i.p. with ChoD but not those from mice injected with PBS responded in vitro with highly spontaneous, as well as phorbol 12-myristate 13-acetate (PMA)-stimulated, production of reactive oxygen species (ROS). However, ChoD significantly reduced the ROS response to PMA in re-stimulated cells in vitro. The cytokine secretion pattern in mice immunized s.c. with ChoD emulsified with incomplete Freund's adjuvant (IFA) showed evidence of Th2-induced or proinflammatory immune responses. The main cytokines detected in sera were interleukin (IL) 6 and 5, tumour necrosis factor α (TNF-α) and monocyte chemoattractant protein 1, while IL-2 and IL-12 as well as interferon γ were undetectable. Similarly, ChoD protein alone activated THP-1-derived macrophages to release proinflammatory IL-6, IL-8 and TNF-α, in vitro. Moreover, a statistically significant predominance of the IgG1 isotype over that of IgG2a in the sera of mice immunized with ChoD/IFA was observed. In conclusion, we demonstrated here that ChoD of Mtb is an active protein, which is able to induce the immune response both in vivo and in vitro.

The sequential assay of interleukin-10 and 13 serum levels in relation to radiographic changes during pulmonary tuberculosis treatment

Background:

We evaluated the sequential changes of interleukin (IL)-10 and IL-13 serum levels with tuberculosis (TB)-related radiographic changes during pulmonary TB (PTB) treatment.

Materials and Methods:

In this cross-sectional study during two consecutive years, forty cases with PTB were recorded, and finally, 24 cases were completed the study. Serum levels of IL-10 and IL-13 were measured on admission time, and 6 months later. Furthermore, chest radiography was performed on admission and 6 months later in the treatment course.

Results:

Radiography at the baseline indicated pulmonary infiltration in all patients (n = 24). Fifteen (62.5%) cases had abnormal and 9 (37.5%) cases had normal radiography at the end of 6 months treatment course. IL-10 and IL-13 upregulated during the treatment time course, and their relationship with radiographic changes shifted from negative (r = −0.14 and P = 0.71) on admission to positive (r = 0.80 and P < 0.001) at the end of 6 months treatment course in normal radiography group. IL-10 level at the start of the treatment was 121.90 ± 88.81 in patients with normal and 82.68 ± 41.50 in patients with abnormal radiography (P = 0.31).

Conclusion:

Sequential increase in IL-10 and IL-13 during PTB treatment course may have a role in clearing the TB-related radiographic infiltration and preventing scar formation.

Prokaryotic Expression, In Vitro Biological Analysis, and In Silico Structural Evaluation of Guinea Pig IL-4

Interleukin-4 is a signature cytokine of T-helper type 2 (Th2) cells that play a major role in shaping immune responses. Its role in highly relevant animal model of tuberculosis (TB) like guinea pig has not been studied till date. In the current study, the guinea pig IL-4 gene was cloned and expressed using a prokaryotic expression vector (pET30 a(+)). This approach yielded a recombinant protein of 19 kDa as confirmed by mass spectrometry analysis and named as recombinant guinea pig (rgp)IL-4 protein. The authenticity of the expression of rgpIL-4 protein was further verified through polyclonal anti-IL4 antiserum raised in rabbits that showed specific and strong binding with the recombinant protein. The biological activity of the rgpIL-4 was ascertained in RAW264.7 cells where LPS-treated nitric oxide (NO) production was found to be suppressed in the presence of this protein. The three-dimensional structure of guinea pig IL-4 was predicted by utilizing the template structure of human interleukin-4, which shared a sequence homology of 58%. The homology modeling result showed clear resemblance of guinea pig IL-4 structure with the human IL-4. Taken together, our study indicates that the newly expressed, biologically active rgpIL-4 protein could provide deeper understanding of the immune responses in guinea pig to different infectious diseases like TB and non-infectious ones.

Hydrogen sulfide dysregulates the immune response by suppressing central carbon metabolism to promote tuberculosis

The ubiquitous gasotransmitter hydrogen sulfide (H₂S) has been recognized to play a crucial role in human health. Using cystathionine γ-lyase (CSE)-deficient mice, we demonstrate an unexpected role of H₂S in Mycobacterium tuberculosis (Mtb) pathogenesis. We showed that Mtb-infected CSE^-/- mice survive longer than WT mice, and support reduced pathology and lower bacterial burdens in the lung, spleen, and liver. Similarly, in vitro Mtb infection of macrophages resulted in reduced colony forming units in CSE^-/- cells. Chemical complementation of infected WT and CSE^-/- macrophages using the slow H₂S releaser GYY3147 and the CSE inhibitor DL-propargylglycine demonstrated that H₂S is the effector molecule regulating Mtb survival in macrophages. Furthermore, we demonstrate that CSE promotes an excessive innate immune response, suppresses the adaptive immune response, and reduces circulating IL-1β, IL-6, TNF-α, and IFN-γ levels in response to Mtb infection. Notably, Mtb infected CSE^-/- macrophages show increased flux through glycolysis and the pentose phosphate pathway, thereby establishing a critical link between H₂S and central metabolism. Our data suggest that excessive H₂S produced by the infected WT mice reduce HIF-1α levels, thereby suppressing glycolysis and production of IL-1β, IL-6, and IL-12, and increasing bacterial burden. Clinical relevance was demonstrated by the spatial distribution of H₂S-producing enzymes in human necrotic, nonnecrotic, and cavitary pulmonary tuberculosis (TB) lesions. In summary, CSE exacerbates TB pathogenesis by altering immunometabolism in mice and inhibiting CSE or modulating glycolysis are potential targets for host-directed TB control.

Nicotine modulates molecules of the innate immune response in epithelial cells and macrophages during infection with M. tuberculosis

Smoking increases susceptibility to becoming infected with and developing tuberculosis. Among the components of cigarette smoke, nicotine has been identified as the main immunomodulatory molecule; however, its effect on the innate immune system is unknown. In the present study, the effect of nicotine on molecules of the innate immune system was evaluated. Lung epithelial cells and macrophages were infected with Mycobacterium tuberculosis (Mtb) and/or treated with nicotine. The results show that nicotine alone decreases the expression of the Toll-like receptors (TLR)-2, TLR-4 and NOD-2 in all three cell types, as well as the production of the SP-D surfactant protein in type II pneumocytes. Moreover, it was observed that nicotine decreases the production of interleukin (IL)-6 and C-C chemokine ligand (CCL)5 during Mtb infection in epithelial cells (EpCs), whereas in macrophages derived from human monocytes (MDMs) there is a decrease in IL-8, IL-6, tumor necrosis factor (TNF)-α, IL-10, CCL2, C-X-C chemokine ligand (CXCL)9 and CXCL10 only during infection with Mtb. Although modulation of the expression of cytokines and chemokines appears to be partially mediated by the nicotinic acetylcholine receptor α7, blocking this receptor found no effect on the expression of receptors and SP-D. In summary, it was found that nicotine modulates the expression of innate immunity molecules necessary for the defense against tuberculosis.

IRAK1 and IRAK4 signaling proteins are dispensable in the response of human neutrophils to Mycobacterium tuberculosis infection

The involvement of neutrophils in the host response to Mycobacterium tuberculosis (Mtb) infection is not as well recognized as the involvement of macrophages and dendritic cells. Thus, this study gives more insight on the impact of the virulent Mtb H37Rv strain on proapoptotic and proinflammatory functions of human neutrophils in vitro. We found that neutrophils are not able to kill Mtb during the infection process, probably due to the lack of reactive oxygen species and nitric oxide production in response to bacteria. However, infected neutrophils effectively released cytokines, chemoattractant interleukin (IL) 8 and proinflammatory IL-1β. Moreover, Mtb enhanced the early apoptosis of neutrophils at 2 h postinfection. Additionally, this proapoptotic and proinflammatory response of neutrophils to Mtb infection occurred in an IRAK1- and IRAK4-independent manner. We also found that Mtb did not affect the surface expression of Toll-like receptor (TLR) 2 and slightly enhanced the surface expression of TLR4, but did not influence mRNA levels of both TLRs during the infection process. In conclusion, we show that the inhibition of signaling proteins activated by MyD88-dependent pathway did not participate in the biological activity of neutrophils against Mtb.

Plasma Levels of Cytokines (IL-10, IFN-γ and TNF-α) in Multidrug Resistant Tuberculosis and Drug Responsive Tuberculosis Patients in Ghana

The emergence of multidrug-resistant tuberculosis (MDR⁻TB) and more recently, extensively drug-resistant (XDR) TB has intensified the need for studies aimed at identifying factors associated with TB drug resistance. This study determined the differences in plasma concentrations of pro-inflammatory (IFN-γ and TNF-α) and anti-inflammatory (IL-10) cytokines in MDR-TB and drug-susceptible (DS) TB patients, in addition to some socio-economic factors. Plasma levels of IL-10, IFN-γ and TNF-α were measured in 83 participants (comprising 49 MDR-TB and 34 DS-TB patients) using sandwich ELISA. Levels of the three cytokines were elevated in MDR-TB patients compared to DS-TB patients. The mean level of IL-10 (7.8 ± 3.61 ρg/mL) measured in MDR-TB cases was relatively higher than those of TNF-α and IFN-γ, and statistically significant (p = 0.0022) when compared to the level of IL-10 (4.8 ± 4.94 ρg/mL) in the DS-TB cases. There were statistically significant associations between MDR-TB and factors such as education level (X² = 9.895, p = 0.043), employment status (X² = 19.404, p = 0.001) and alcoholism (X² = 3.971, p = 0.046). This study adds to the knowledge that IFN-γ, TNF-α and IL-10 play a role in the host response to Mycobacterium tuberculosis (MTB). Alcohol intake can be considered as an important MDR-TB risk factor.