Immunogenic membrane-associated proteins of Mycobacterium tuberculosis revealed by proteomics

Microbiology ◽  
2005 ◽  
Vol 151 (7) ◽  
pp. 2411-2419 ◽  
Author(s):  
Sudhir Sinha ◽  
K. Kosalai ◽  
Shalini Arora ◽  
Abdelkader Namane ◽  
Pawan Sharma ◽  
...  

Membrane-associated proteins of Mycobacterium tuberculosis offer a challenge, as well as an opportunity, in the quest for better therapeutic and prophylactic interventions against tuberculosis. The authors have previously reported that extraction with the detergent Triton X-114 (TX-114) is a useful step in proteomic analysis of mycobacterial cell membranes, and detergent-soluble membrane proteins of mycobacteria are potent stimulators of human T cells. In this study 1-D and 2-D gel electrophoresis-based protocols were used for the analysis of proteins in the TX-114 extract of M. tuberculosis membranes. Peptide mass mapping (using MALDI-TOF-MS, matrix assisted laser desorption/ionization time of flight mass spectrometry) of 116 samples led to the identification of 105 proteins, 9 of which were new to the M. tuberculosis proteome. Functional orthologues of 73 of these proteins were also present in Mycobacterium leprae, suggesting their relative importance. Bioinformatics predicted that as many as 73 % of the proteins had a hydrophobic disposition. 1-D gel electrophoresis revealed more hydrophobic/transmembrane and basic proteins than 2-D gel electrophoresis. Identified proteins fell into the following major categories: protein synthesis, cell wall biogenesis/architecture and conserved hypotheticals/unknowns. To identify immunodominant proteins of the detergent phase (DP), 14 low-molecular-mass fractions prepared by continuous-elution gel electrophoresis were subjected to T cell activation assays using blood samples from BCG-vaccinated healthy donors from a tuberculosis endemic area. Analysis of the responses (cell proliferation and IFN-γ production) showed that the immunodominance of certain DP fractions was most probably due to ribosomal proteins, which is consistent with both their specificity for mycobacteria and their abundance. Other membrane-associated proteins, including transmembrane proteins/lipoproteins and ESAT-6, did not appear to contribute significantly to the observed T cell responses.

Blood ◽  
1993 ◽  
Vol 81 (6) ◽  
pp. 1521-1526 ◽  
Author(s):  
TJ Smith ◽  
N Terada ◽  
CC Robinson ◽  
EW Gelfand

Acute infectious mononucleosis (AIM) is caused by the Epstein-Barr virus (EBV) and is characterized by a proliferation of atypical lymphocytes, predominantly CD8+ T cells. Various diseases associated with T-cell activation have been shown to stimulate the selective expansion of certain V beta (variable region of the T-cell receptor beta chain) expressing T-cell populations. The purpose of this investigation was to determine if the proliferation of T cells accompanying AIM is associated with selective expression/expansion of distinct populations of V beta T cells. We determined V beta expression in eight patients with clinical and laboratory evidence of AIM, including an atypical lymphocytosis. Gel electrophoresis and quantitative analysis were performed on cDNA amplified by the polymerase chain reaction (PCR) using different V beta region primers. Gel electrophoresis analysis showed prominent V beta 6.1–3 and V beta 7 bands in all eight patients with AIM but not in the controls. Quantitative PCR analysis showed that the V beta 6.1–3 and V beta 7 mean PCR ratios increased, respectively, from 163.0 +/- 22.5 and 142.3 +/- 5.5 in controls to 339.9 +/- 38.8 (P < .03) and 396.1 +/- 45.6 (P < .01) in the eight patients with AIM. Two of the eight patients who had increased V beta 6.1–3 and V beta 7 expression were retested after clinical resolution of AIM and no longer had evidence of increased V beta 6.1–3 and V beta 7 T-cell expression. AIM is associated with a selective increased expression of V beta 6.1–3 and V beta 7 T cells present at the time of initial clinical symptoms and atypical lymphocytosis. This increased expression resolves following recovery from AIM. This V beta-specific selective expression resembles the super- antigen response seen after staphylococcal toxin stimulation and may be caused by EBV triggering of selective expansion of V beta 6.1–3 and V beta 7 T-cell subsets.


2005 ◽  
Vol 360 (1461) ◽  
pp. 1663-1672 ◽  
Author(s):  
Karina F Meiri

The ability of polarized cells to initiate and sustain directional responses to extracellular signals is critically dependent on direct communication between spatially organized signalling modules in the membrane and the underlying cytoskeleton. Pioneering work in T cells has shown that the assembly of signalling modules critically depends on the functional compartmentalization of membrane lipids into ordered microdomains or lipid rafts. The significance of rafts in T cell activation lies not only in their ability to recruit the signalling partners that eventually assemble into a mature immunological synapse but also in their ability to regulate actin dynamics and recruit cytoskeletal associated proteins, thereby achieving the structural polarization underlying stability of the synapse—a critical prerequisite for activation to be sustained. Lipid rafts vary quite considerably in size and visualizing the smallest of them in vivo has been challenging. Nonetheless it is now been shown quite convincingly that a surprisingly large proportion—in the order of 50%—of external membrane lipids (chiefly cholesterol and glycosphingolipids) can be dynamically localized in these liquid ordered rafts. Complementary inner leaflet rafts are less well characterized, but contain phosphoinositides as an important functional component that is crucial for regulating the behaviour of the actin cytoskeleton. This paper provides an overview of the interdependency between signalling and cytoskeletal polarization, and in particular considers how regulation of the cytoskeleton plays a crucial role in the consolidation of rafts and their stabilization into the immunological synapse.


2000 ◽  
Vol 68 (2) ◽  
pp. 621-629 ◽  
Author(s):  
Peter Andersen ◽  
Birgitte Smedegaard

ABSTRACT We have studied CD4+ T cells that mediate immunological memory to an intravenous infection with Mycobacterium tuberculosis. The studies were conducted with a mouse model of memory immunity in which mice are rendered immune by a primary infection followed by antibiotic treatment and rest. Shortly after reinfection, tuberculosis-specific memory cells were recruited from the recirculating pool, leading to rapidly increasing precursor frequencies in the liver and a simultaneous decrease in the blood. A small subset of the infiltrating T cells was rapidly activated (<20 h) and expressed high levels of intracellular gamma interferon and the T-cell activation markers CD69 and CD25. These memory effector T cells expressed intermediate levels of CD45RB and were heterogeneous with regard to the L-selectin and CD44 markers. By adoptive transfer into nude mice, the highest level of resistance to a challenge with M. tuberculosis was mediated by CD45RBhigh,l-selectinhigh, CD44low cells. Taken together, these two lines of evidence support an important role for memory cells which have reverted to a naive phenotype in the long-term protection against M. tuberculosis.


mBio ◽  
2021 ◽  
Author(s):  
Shibali Das ◽  
Nancy D. Marin ◽  
Ekaterina Esaulova ◽  
Mushtaq Ahmed ◽  
Amanda Swain ◽  
...  

Tuberculosis is a leading cause of death due to single infectious agent accounting 1.4 million deaths each year. The only licensed vaccine, BCG, is not effective due to variable efficacy.


2020 ◽  
Author(s):  
Cheleka A.M. Mpande ◽  
Virginie Rozot ◽  
Boitumelo Mosito ◽  
Munyaradzi Musvosvi ◽  
One B Dintwe ◽  
...  

AbstractBackgroundRecent Mycobacterium tuberculosis (M.tb) infection is associated with a higher risk of progression to tuberculosis disease, compared to persistent infection after remote exposure. However, current immunodiagnostic tools fail to distinguish between recent and remote infection. We aimed to characterise the immunobiology associated with acquisition of M.tb infection and identify a biomarker that can distinguish recent from remote infection.MethodsHealthy South African adolescents were serially tested with QuantiFERON-TB Gold to define recent (QuantiFERON-TB conversion <6 months) and persistent (QuantiFERON-TB+ for >1.5 year) infection. We characterized M.tb-specific CD4 T cell functional (IFN-γ, TNF, IL-2, CD107, CD154), memory (CD45RA, CCR7, CD27, KLRG-1) and activation (HLA-DR) profiles by flow cytometry after CFP-10/ESAT-6 peptide pool or M.tb lysate stimulation. We then assessed the diagnostic performance of immune profiles that were differentially expressed between individuals with recent or persistent QuantiFERON-TB+.FindingsCFP-10/ESAT-6-specific CD4 T cell activation but not functional or memory phenotypes distinguished between individuals with recent and persistent QuantiFERON-TB+. In response to M.tb lysate, recent QuantiFERON-TB+ individuals had lower proportions of highly differentiated IFN-γ+TNF+ CD4 T cells expressing a KLRG-1+ effector phenotype and higher proportions of early differentiated IFN-γ-TNF+IL-2+ and activated CD4 T cells compared to persistent QuantiFERON-TB+ individuals. Among all differentially expressed T cell features CFP-10/ESAT-6-specific CD4 T cell activation was the best performing diagnostic biomarker of recent infection.InterpretationRecent M.tb infection is associated with highly activated and moderately differentiated functional M.tb-specific T cell subsets, that can be used as biomarkers to distinguish between recent and remote infection.


Blood ◽  
1993 ◽  
Vol 81 (6) ◽  
pp. 1521-1526 ◽  
Author(s):  
TJ Smith ◽  
N Terada ◽  
CC Robinson ◽  
EW Gelfand

Abstract Acute infectious mononucleosis (AIM) is caused by the Epstein-Barr virus (EBV) and is characterized by a proliferation of atypical lymphocytes, predominantly CD8+ T cells. Various diseases associated with T-cell activation have been shown to stimulate the selective expansion of certain V beta (variable region of the T-cell receptor beta chain) expressing T-cell populations. The purpose of this investigation was to determine if the proliferation of T cells accompanying AIM is associated with selective expression/expansion of distinct populations of V beta T cells. We determined V beta expression in eight patients with clinical and laboratory evidence of AIM, including an atypical lymphocytosis. Gel electrophoresis and quantitative analysis were performed on cDNA amplified by the polymerase chain reaction (PCR) using different V beta region primers. Gel electrophoresis analysis showed prominent V beta 6.1–3 and V beta 7 bands in all eight patients with AIM but not in the controls. Quantitative PCR analysis showed that the V beta 6.1–3 and V beta 7 mean PCR ratios increased, respectively, from 163.0 +/- 22.5 and 142.3 +/- 5.5 in controls to 339.9 +/- 38.8 (P < .03) and 396.1 +/- 45.6 (P < .01) in the eight patients with AIM. Two of the eight patients who had increased V beta 6.1–3 and V beta 7 expression were retested after clinical resolution of AIM and no longer had evidence of increased V beta 6.1–3 and V beta 7 T-cell expression. AIM is associated with a selective increased expression of V beta 6.1–3 and V beta 7 T cells present at the time of initial clinical symptoms and atypical lymphocytosis. This increased expression resolves following recovery from AIM. This V beta-specific selective expression resembles the super- antigen response seen after staphylococcal toxin stimulation and may be caused by EBV triggering of selective expansion of V beta 6.1–3 and V beta 7 T-cell subsets.


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