scholarly journals Novel epitopes identified from efflux pumps ofMycobacterium tuberculosiscould induce cytotoxic T lymphocyte response

PeerJ ◽  
2015 ◽  
Vol 3 ◽  
pp. e1229 ◽  
Author(s):  
Ming-xia Zhai ◽  
Fei Chen ◽  
Yuan-yuan Zhao ◽  
Ya-hong Wu ◽  
Guo-dong Li ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Mycobacterium Tuberculosis ◽  
Efflux Pump ◽  
Cytotoxic T Lymphocyte ◽  
Efflux Pumps ◽  
Common Mechanism ◽  
Antigenic Peptides ◽  
Ifn Γ ◽  
Cytotoxic T Lymphocyte Response

Overcoming drug-resistance is one of the major challenges to control tuberculosis (TB). The up-regulation of efflux pumps is one common mechanism that leads to drug-resistance. Therefore, immunotherapy targeting these efflux pump antigens could be promising strategy to be combined with current chemotherapy. Considering that CD8+ cytotoxic T lymphocytes (CTLs) induced by antigenic peptides (epitopes) could elicit HLA-restricted anti-TB immune response, efflux pumps from classical ABC family (Mycobacterium tuberculosis, Mtb) were chosen as target antigens to identify CTL epitopes. HLA-A2 restricted candidate peptides from Rv2937, Rv2686c and Rv2687c ofMycobacterium tuberculosiswere predicted, synthesized and tested. Five peptides could induce IFN-γ release and cytotoxic activity in PBMCs from HLA-A2+PPD+donors. Results from HLA-A2/Kbtransgenic mice immunization assay suggested that four peptides Rv2937-p168, Rv2937-p266, Rv2686c-p151, and Rv2686c-p181 could induce significant CTL responsein vivo. These results suggested that these novel epitopes could be used as immunotherapy candidates to TB drug-resistance.

scholarly journals Novel epitopes identified from efflux pumps of Mycobacterium tuberculosis could induce cytotoxic T lymphocyte response

2015 ◽  
Author(s):  
Mingxia Zhai ◽  
Fei Chen ◽  
Yuanyuan Zhao ◽  
Yahong Wu ◽  
Guodong Li ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Mycobacterium Tuberculosis ◽  
Efflux Pump ◽  
Cytotoxic T Lymphocyte ◽  
Efflux Pumps ◽  
Common Mechanism ◽  
Antigenic Peptides ◽  
Ifn Γ ◽  
Cytotoxic T Lymphocyte Response

Overcoming drug-resistance is one of the major challenges to control tuberculosis (TB). The up-regulation of efflux pumps is one common mechanism that leads to drug-resistance. Therefore, immunotherapy targeting these efflux pump antigens could be promising strategy to be combined with current chemotherapy. Considering that CD8+ cytotoxic T lymphocytes (CTLs) induced by antigenic peptides (epitopes) could elicit HLA-restricted anti-TB immune response, efflux pumps from classical ABC family (Mycobacterium tuberculosis, Mtb) were chosen as target antigens to identify CTL epitopes. HLA-A2 restricted candidate peptides from Rv2937, Rv2686c and Rv2687c of Mycobacterium tuberculosis were predicted, synthesized and tested. Five peptides could induce IFN-γ release and cytotoxic activity in PBMCs from HLA-A2+ PPD+ donors. Results from HLA-A2/Kb transgenic mice immunization assay suggested that four peptides Rv2937-p168, Rv2937-p266, Rv2686c-p151, and Rv2686c-p181 could induce significant CTL response in vivo. These results suggested that these novel epitopes could be used as immunotherapy candidates to TB drug-resistance.

scholarly journals Novel epitopes identified from efflux pumps of Mycobacterium tuberculosis could induce cytotoxic T lymphocyte response

2015 ◽  
Author(s):  
Mingxia Zhai ◽  
Fei Chen ◽  
Yuanyuan Zhao ◽  
Yahong Wu ◽  
Guodong Li ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Mycobacterium Tuberculosis ◽  
Efflux Pump ◽  
Cytotoxic T Lymphocyte ◽  
Efflux Pumps ◽  
Common Mechanism ◽  
Antigenic Peptides ◽  
Ifn Γ ◽  
Cytotoxic T Lymphocyte Response

Overcoming drug-resistance is one of the major challenges to control tuberculosis (TB). The up-regulation of efflux pumps is one common mechanism that leads to drug-resistance. Therefore, immunotherapy targeting these efflux pump antigens could be promising strategy to be combined with current chemotherapy. Considering that CD8+ cytotoxic T lymphocytes (CTLs) induced by antigenic peptides (epitopes) could elicit HLA-restricted anti-TB immune response, efflux pumps from classical ABC family (Mycobacterium tuberculosis, Mtb) were chosen as target antigens to identify CTL epitopes. HLA-A2 restricted candidate peptides from Rv2937, Rv2686c and Rv2687c of Mycobacterium tuberculosis were predicted, synthesized and tested. Five peptides could induce IFN-γ release and cytotoxic activity in PBMCs from HLA-A2+ PPD+ donors. Results from HLA-A2/Kb transgenic mice immunization assay suggested that four peptides Rv2937-p168, Rv2937-p266, Rv2686c-p151, and Rv2686c-p181 could induce significant CTL response in vivo. These results suggested that these novel epitopes could be used as immunotherapy candidates to TB drug-resistance.

scholarly journals Antileishmanial Aminopyrazoles: Studies into Mechanisms and Stability of Experimental Drug Resistance

2020 ◽  
Vol 64 (9) ◽  
Author(s):  
M. Van den Kerkhof ◽  
D. Mabille ◽  
S. Hendrickx ◽  
P. Leprohon ◽  
C. E. Mowbray ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Copy Number ◽  
Efflux Pump ◽  
Efflux Pumps ◽  
Copy Number Variations ◽  
Content Type ◽  
Development Of Resistance ◽  
Efflux Pump Inhibitors

ABSTRACT Current antileishmanial treatment is hampered by limitations, such as drug toxicity and the risk of treatment failure, which may be related to parasitic drug resistance. Given the urgent need for novel drugs, the Drugs for Neglected Diseases initiative (DNDi) has undertaken a drug discovery program, which has resulted in the identification of aminopyrazoles, a highly promising antileishmanial chemical series. Multiple experiments have been performed to anticipate the propensity for resistance development. Resistance selection was performed by successive exposure of Leishmania infantum promastigotes (in vitro) and intracellular amastigotes (both in vitro and in golden Syrian hamsters). The stability of the resistant phenotypes was assessed after passage in mice and Lutzomyia longipalpis sandflies. Whole-genome sequencing (WGS) was performed to identify mutated genes, copy number variations (CNVs), and somy changes. The potential role of efflux pumps (the MDR and MRP efflux pumps) in the development of resistance was assessed by coincubation of aminopyrazoles with specific efflux pump inhibitors (verapamil, cyclosporine, and probenecid). Repeated drug exposure of amastigotes did not result in the emergence of drug resistance either in vitro or in vivo. Selection at the promastigote stage, however, was able to select for parasites with reduced susceptibility (resistance index, 5.8 to 24.5). This phenotype proved to be unstable after in vivo passage in mice and sandflies, suggesting that nonfixed alterations are responsible for the elevated resistance. In line with this, single nucleotide polymorphisms and indels identified by whole-genome sequencing could not be directly linked to the decreased drug susceptibility. Copy number variations were absent, whereas somy changes were detected, which may have accounted for the transient acquisition of resistance. Finally, aminopyrazole activity was not influenced by the MDR and MRP efflux pump inhibitors tested. The selection performed does not suggest the rapid development of resistance against aminopyrazoles in the field. Karyotype changes may confer elevated levels of resistance, but these do not seem to be stable in the vertebrate and invertebrate hosts. MDR/MRP efflux pumps are not likely to significantly impact the activity of the aminopyrazole leads.

scholarly journals High efflux pump activity and gene expression at baseline linked to poor tuberculosis treatment outcomes

2017 ◽  
Vol 6 (1) ◽  
pp. 8-17
Author(s):  
S. Mazando ◽  
C. Zimudzi ◽  
M. Zimba ◽  
S. Sande ◽  
M. Gundidza ◽  
...  
Keyword(s):  
Gene Expression ◽  
Drug Resistance ◽  
Mycobacterium Tuberculosis ◽  
Ethidium Bromide ◽  
Efflux Pump ◽  
Efflux Pumps ◽  
Drug Tolerance ◽  
Tuberculosis Treatment ◽  
Expression Levels ◽  
Pump Activity

Phenotypic TB drug resistance, also known as drug tolerance, has been previously attributed to slowed bacterial growth in vivo. The increased activity and expression of efflux systems can lower the intracellular concentration of many antibiotics thus reducing their efficacy. We hypothesized that efflux pump activation and expression could be a risk factor for TB drug tolerance in patients initiated on treatment. Analyses of gene expression levels of six select efflux pumps associated with drug tolerance in Mycobacterium tuberculosis and its correlation with the cell’s ability to efflux ethidium bromide (a common efflux substrate) were assayed. Efflux pump gene expression differed significantly between the strains from treatment failures and treatment successes. Efflux of ethidium bromide by M. tuberculosis isolates revealed that isolates from treatment failures rapidly efflux ethidium bromide more than isolates from treatment successes or the H37Rv control strains. The efflux pumps efpA, jefA (Rv2459c), Rv1258c, p55 and mmpL7 may have a role in TB drug tolerance. Quantifying the expression levels of M. tuberculosis efflux pump genes may be a new method to diagnose clinically persistent tuberculosis. High efflux pump activity and expression at baseline can be associated with tuberculosis treatment failure even when the Mycobacterium tuberculosis does not have established resistance mutations.Journal of Medical and Biomedical Sciences (2017) 6(1), 8-17Keywords: drug resistance, Efflux, Mycobacterium tuberculosis, expression, treatment outcome

scholarly journals Role of the Mycobacterium tuberculosis P55 Efflux Pump in Intrinsic Drug Resistance, Oxidative Stress Responses, and Growth

2009 ◽  
Vol 53 (9) ◽  
pp. 3675-3682 ◽  
Author(s):  
Santiago Ramón-García ◽  
Carlos Martín ◽  
Charles J. Thompson ◽  
José A. Aínsa
Keyword(s):  
Oxidative Stress ◽  
Drug Resistance ◽  
Cell Wall ◽  
Mycobacterium Tuberculosis ◽  
Stress Responses ◽  
Efflux Pump ◽  
Efflux Pumps ◽  
Oxidative Stress Responses

ABSTRACT Bacterial efflux pumps have traditionally been studied as low-level drug resistance determinants. Recent insights have suggested that efflux systems are often involved with fundamental cellular physiological processes, suggesting that drug extrusion may be a secondary function. In Mycobacterium tuberculosis, little is known about the physiological or drug resistance roles of efflux pumps. Using Mycobacterium bovis BCG as a model system, we showed that deletion of the Rv1410c gene encoding the P55 efflux pump made the strain more susceptible to a range of toxic compounds, including rifampin (rifampicin) and clofazimine, which are first- and second-line antituberculosis drugs. The efflux pump inhibitors carbonyl cyanide m-chlorophenylhydrazone (CCCP) and valinomycin inhibited the P55-determined drug resistance, suggesting the active export of the compounds by use of the transmembrane proton and electrochemical gradients as sources of energy. In addition, the P55 efflux pump mutant was more susceptible to redox compounds and displayed increased intracellular redox potential, suggesting an essential role of the efflux pump in detoxification processes coupled to oxidative balance within the cell. Finally, cells that lacked the p55 gene displayed smaller colony sizes and had a growth defect in liquid culture. This, together with an increased susceptibility to the cell wall-targeting compounds bacitracin and vancomycin, suggested that P55 is needed for proper cell wall assembly and normal growth in vitro. Thus, P55 plays a fundamental role in oxidative stress responses and in vitro cell growth, in addition to contributing to intrinsic antibiotic resistance. Inhibitors of the P55 efflux pump could help to improve current treatments for tuberculosis.

scholarly journals Lentiviral Transduction of Dendritic Cells Confers Protective Antiviral Immunity In Vivo

2004 ◽  
Vol 78 (14) ◽  
pp. 7843-7845 ◽  
Author(s):  
Shohreh Zarei ◽  
Shahnaz Abraham ◽  
Jean-Francois Arrighi ◽  
Olivier Haller ◽  
Thomas Calzascia ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Viral Infections ◽  
Cytotoxic T Lymphocyte ◽  
Antiviral Immunity ◽  
Lymphocytic Choriomeningitis ◽  
Lymphocyte Response ◽  
Vaccine Candidates ◽  
Virus Model ◽  
Cytotoxic T Lymphocyte Response

ABSTRACT Control of a viral infection in vivo requires a rapid and efficient cytotoxic-T-lymphocyte response. We demonstrate that lentivirus-mediated introduction of antigen in dendritic cells confers a protective antiviral immunity in vivo in a lymphocytic choriomeningitis virus model. Therefore, lentiviral vectors may be excellent vaccine candidates for viral infections.

scholarly journals Urban airborne particle exposure impairs human lung and blood Mycobacterium tuberculosis immunity

Thorax ◽  
2019 ◽  
Vol 74 (7) ◽  
pp. 675-683 ◽  
Author(s):  
Martha Torres ◽  
Claudia Carranza ◽  
Srijata Sarkar ◽  
Yolanda Gonzalez ◽  
Alvaro Osornio Vargas ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Mexico City ◽  
Mononuclear Cells ◽  
Immune Cell ◽  
Human Lung ◽  
Constitutive Expression ◽  
In Vitro Exposure ◽  
Ifn Γ

RationaleAssociations between urban (outdoor) airborne particulate matter (PM) exposure and TB and potential biological mechanisms are poorly explored.ObjectivesTo examine whether in vivo exposure to urban outdoor PM in Mexico City and in vitro exposure to urban outdoor PM2.5 (< 2.5 µm median aerodynamic diameter) alters human host immune cell responses to Mycobacterium tuberculosis.MethodsCellular toxicity (flow cytometry, proliferation assay (MTS assay)), M. tuberculosis and PM2.5 phagocytosis (microscopy), cytokine-producing cells (Enzyme-linked immune absorbent spot (ELISPOT)), and signalling pathway markers (western blot) were examined in bronchoalveolar cells (BAC) and peripheral blood mononuclear cells (PBMC) from healthy, non-smoking, residents of Mexico City (n=35; 13 female, 22 male). In vivo-acquired PM burden in alveolar macrophages (AM) was measured by digital image analysis.Measurements and main resultsIn vitro exposure of AM to PM2.5 did not affect M. tuberculosis phagocytosis. High in vivo-acquired AM PM burden reduced constitutive, M. tuberculosis and PM-induced interleukin-1β production in freshly isolated BAC but not in autologous PBMC while it reduced constitutive production of tumour necrosis factor-alpha in both BAC and PBMC. Further, PM burden was positively correlated with constitutive, PM, M. tuberculosis and purified protein derivative (PPD)-induced interferon gamma (IFN-γ) in BAC, and negatively correlated with PPD-induced IFN-γ in PBMC.ConclusionsInhalation exposure to urban air pollution PM impairs important components of the protective human lung and systemic immune response against M. tuberculosis. PM load in AM is correlated with altered M. tuberculosis-induced cytokine production in the lung and systemic compartments. Chronic PM exposure with high constitutive expression of proinflammatory cytokines results in relative cellular unresponsiveness.

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