The Immune Response to Mycobacterium tuberculosis Infection in Humans

Handzel, Zeev T.

doi:10.5772/54986

Cited by 5 publications

(3 citation statements)

References 52 publications

(61 reference statements)

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“…Mycobacterium tuberculosis (Mtb) is the causative agent of tuberculosis, a chronic infectious lung disease that affects over one-third of the global population and causes 8 million new cases per year ( Theodor, 2013 ; Ramazanzadeh et al, 2015 ). Mtb secrete the protein ESAT-6 by the ESX-1 type VII secretion system, increasing Ca 2 + influx inside the cell, activating calpain, a cysteine protease, which finally allows the release of NETs structures through a pathway similar to the activation produced by ionomycin ( Francis et al, 2014 ).…”

Section: Role Of Neutrophil Extracellular Trap During Bacterial Infec...mentioning

confidence: 99%

Role of Extracellular Trap Release During Bacterial and Viral Infection

et al. 2022

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Neutrophils are innate immune cells that play an essential role during the clearance of pathogens that can release chromatin structures coated by several cytoplasmatic and granular antibacterial proteins, called neutrophil extracellular traps (NETs). These supra-molecular structures are produced to kill or immobilize several types of microorganisms, including bacteria and viruses. The contribution of the NET release process (or NETosis) to acute inflammation or the prevention of pathogen spreading depends on the specific microorganism involved in triggering this response. Furthermore, studies highlight the role of innate cells different from neutrophils in triggering the release of extracellular traps during bacterial infection. This review summarizes the contribution of NETs during bacterial and viral infections, explaining the molecular mechanisms involved in their formation and the relationship with different components of such pathogens.

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Section: Role Of Neutrophil Extracellular Trap During Bacterial Infec...mentioning

confidence: 99%

Role of Extracellular Trap Release During Bacterial and Viral Infection

et al. 2022

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“…Infection with MTBC does not necessarily imply having the TB disease. There are three main possible outcomes upon entry into the lungs: (1) the innate immunity may be able to clear the pathogen leading to no disease, (2) the pathogen may be contained in the lungs to form granuloma by attracting other immune effector cells to surround the activated macrophages to reduce tissue damage and proliferation of the bacteria, thereby leading to establishment of latent TB infection, and (3) the immune system may not be able to keep the pathogen under check, allowing an active replication of the bacilli and hence leading to active TB disease (Handzel, 2013;de Martino et al, 2014de Martino et al, , 2019. These outcomes of TB infections can be attributed to the host immune response, the environmental conditions, and the bacterial factors such as its virulence (Handzel, 2013).…”

Section: Introductionmentioning

confidence: 99%

Bacterial Load Comparison of the Three Main Lineages of Mycobacterium tuberculosis Complex in West Africa

et al. 2021

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Studies have shown an association between bacterial load and virulence; however, not much is known about the diversity in this phenotypic characteristic of Mycobacterium tuberculosis complex (MTBC). This study was therefore aimed to determine the differences in bacterial load of the three most prevalent MTBC genotypes (L4, L5, and L6) in West Africa at the time of diagnosis. A total of 170 paired fresh sputum samples were collected; one part in guanidinium thiocyanate (GTC) was used for RNA extraction and tuberculosis molecular bacterial load assay (TB-MBLA), and the other part without GTC was confirmed for TB positivity using GeneXpert MTB/RIF, smear microscopy grading, and culture on Löwenstein–Jensen media slants. The 170 sputum samples comprised 155 new cases, three follow-up cases, and 12 TB negative sputum samples. The time-to-culture positivity (TTP) and degree of culture positivity (DCP) were recorded. All 122 isolates obtained were spoligotyped for lineage (L) classification, but spoligotypes were obtained from 120 isolates. Of the typed isolates, 70.0, 10.8, 10.8, 4.2, 2.5, 0.8, and 0.8% were lineages 4, 5, 6, 2, 3, 1, and Mycobacterium bovis, respectively. Further analysis of the three most prevalent lineages showed significantly shorter TTP and higher DCP by L4 compared to L5 and L6, respectively: TTP 20.8, vs. 26.5, and 28.2 days; p-value = 0.005 and DCP 1.27, vs. 0.81 and 0.29, p < 0.001. The average TB-MBLA measured bacterial load of L4 was 3.82 Log10eCFU/ml which was not significantly different from 3.81 and 3.80 Log10eCFU/ml of L5 and L6, respectively, p = 0.84. Degrees of smear microscopy L4 = 1.20, L5 = 1.20, and L6 = 0.92 and GeneXpert Cq values L4 = 17.08, L5 = 18.37, and L6 = 17.59 showed no significant difference between the lineages, p = 0.72 and p = 0.48, respectively. Retrospective analysis of a larger sample confirmed the difference in TTP, p < 0.001. In conclusion, the observed shorter TTP and high DCP of L4 could signify high growth rate in culture that is independent of total bacterial load at diagnosis.

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“…Tuberculosis is a cosmopolitan infectious disease infecting about one third of the world's population, although only 10% of those people develop clinical disease. One of the most important features of the causative agents (M. tuberculosis) is that they lack structurally variable strains, and have similar virulence capacity inside the host (Handzel, 2013). Accordingly, it is reasonable to assume that same morbidity and mortality occur in different populations when there are similar environmental and socioeconomical conditions.…”

Section: Introductionmentioning

confidence: 99%

The Impact of Toll-Like Receptor 2 Genetic Variations on Susceptibility to Tuberculosis

Jabbar Altamimi,

Muhsin Ali

2017

Qad Med J

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Background: Tuberculosis is a disease of worldwide distribution. This disease is known to caused by Mycobacterium tuberculosis, however several environmental and genetic factors can affect the occurrence and progression of the disease. Toll-like receptor 2 (TLR2) has a particular importance in immune response against this bacteria.Aims: This study aimed to investigate the association of two single nuclotide polymorphisms(SNPs) in TLR2 gene which are Arg677Trp and Arg753Gln with the incidence of TB in Iraqi patients.Subject and Methods: A case-control study was conducted which involved 55 patients with confirmed pulmonary TB and other age-matched unrelated 30 healthy individuals as control group. Blood samples were obtained from each subject and DNA was extracted. The gene of TLR2 was amplified with polymerase chain reaction (PCR) using specific sets of primers. Genotyping was achieved by direct sequencing.Results: Only the SNPArg753Gln appeared in two genotypes which were GG and AG in both TB patients and control groups. In TB patients, these genotypes account for 44 (85.45%) and 11 (14.55%) respectively, compared with 29 (96.7%) and 1 (3.3%) respectively in control group with significant difference (OR =7.251 95% CI=1.008-59.211, P = 0.035). The SNP Arg677Trp had only one genotype which was CC.Conclusion: The allele A of the SNP Arg753Gln could be considered as a risk factor for TB among Iraqi patients.

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The Immune Response to Mycobacterium tuberculosis Infection in Humans

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Cited by 5 publications

References 52 publications

Role of Extracellular Trap Release During Bacterial and Viral Infection

Role of Extracellular Trap Release During Bacterial and Viral Infection

Bacterial Load Comparison of the Three Main Lineages of Mycobacterium tuberculosis Complex in West Africa

The Impact of Toll-Like Receptor 2 Genetic Variations on Susceptibility to Tuberculosis

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