Biochemical and cultural analysis of mycobacterial recombinants obtained by spheroplast fusion

Rastogi, Nalin; Rauzier, J.Y.; Papa, F; David, Hugo L.

doi:10.1016/s0769-2609(86)80018-7

Cited by 3 publications

(3 citation statements)

References 12 publications

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“…There are reports that show cross-reactive antibodies generated by exposure to environmental mycobacteria or non-pathogenic enteric or pulmonary bacteria [ 56 , 57 ]. It has also been shown that the development of low level humoral immune responses to Mycobacterium avium sonic extracts and mycobacterial LAM in children correlates with increasing age, and by 18 years of age many individuals were sero-reactive to mycobacterial antigens [ 58 ].…”

Section: Discussionmentioning

confidence: 99%

IgA and IgG against Mycobacterium tuberculosis Rv2031 discriminate between pulmonary tuberculosis patients, Mycobacterium tuberculosis-infected and non-infected individuals

et al. 2018

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As part of a major project to investigate protective and diagnostic immune markers against tuberculosis (TB), we measured antibody isotype responses to Mycobacterium tuberculosis (Mtb) antigens (LAM, Rv2031, and HBHA) in cohorts of 149 pulmonary tuberculosis patients (PTBP), 148 household contacts (HHCs), and 68 community controls (CCs) in an endemic setting. ELISA was used to measure levels of IgA, IgG, and IgM from sera of cohorts at baseline, and at 6 and 12 months from entry. The results show that there were significant differences in IgA, IgG, and IgM responses to the different antigens and in the three cohorts. At baseline, the level of IgM against RV2031 and LAM did not vary between cohorts, but the levels of IgA and IgG against Rv2031 were significantly higher in PTB patients than HHCs and CCs, followed by HHCs, and the lowest in CCs. In patients, there was a significant variation in antibody responses before and after chemotherapy. The levels of IgA and IgG against HBHA, and IgA against Rv2031 decreased significantly and remained low, while IgA and IgG against LAM increased significantly and remained high following chemotherapy. However, the levels of IgM against Rv2031 and LAM increased at 6 months but decreased again at 12 months. IgM against HBHA did not show any significant variation before and after chemotherapy. Similarly, there were also significant variations in antibody responses in HHCs over time. Our results show that there are significant variations in IgA, IgG and IgM responses to the different antigens and in the three cohorts, implying that not all antibody isotype responses are markers of clinical TB. In addition, the current and previous studies consistently show that IgA and IgG against Rv2031 discriminate between clinical disease, Mtb-infected and non-infected individuals.

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Section: Discussionmentioning

confidence: 99%

IgA and IgG against Mycobacterium tuberculosis Rv2031 discriminate between pulmonary tuberculosis patients, Mycobacterium tuberculosis-infected and non-infected individuals

et al. 2018

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“…The fact that early studies on mycobacterial capsule were performed in two host-grown species, M. leprae and M. lepraemurium, and the fact that both species are known to release large amounts of specific lipids, such as glycopeptidolipid (GPL), suggested that the capsule was an accumulation of those lipids within the phagosomal membrane. However, this was later ruled out when the presence of capsule could be confirmed in other mycobacterial species growing in axenic cultures, which exhibit an impaired or highly reduced ability to release these lipids [39]. Importantly, the use of ruthenium red and peroxidase-conjugated concanavalin A in these studies suggested the polysaccharide nature of this compartment [39,40].…”

Section: Structure and Biosynthesis Of Mtb Capsulementioning

confidence: 99%

“…However, this was later ruled out when the presence of capsule could be confirmed in other mycobacterial species growing in axenic cultures, which exhibit an impaired or highly reduced ability to release these lipids [39]. Importantly, the use of ruthenium red and peroxidase-conjugated concanavalin A in these studies suggested the polysaccharide nature of this compartment [39,40]. More recent work, pioneered primarily by Daffe’s group, demonstrated that the mycobacterial capsule consists of neutral polysaccharides, proteins and lower amounts of lipids [25,26].…”

Section: Structure and Biosynthesis Of Mtb Capsulementioning

confidence: 99%

TheMycobacterium tuberculosiscapsule: a cell structure with key implications in pathogenesis

Kalscheuer

Palacios

Anso

et al. 2019

Biochemical Journal

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Bacterial capsules have evolved to be at the forefront of the cell envelope, making them an essential element of bacterial biology. Efforts to understand the Mycobacterium tuberculosis (Mtb) capsule began more than 60 years ago, but the relatively recent development of mycobacterial genetics combined with improved chemical and immunological tools have revealed a more refined view of capsule molecular composition. A glycogen-like α-glucan is the major constituent of the capsule, with lower amounts of arabinomannan and mannan, proteins and lipids. The major Mtb capsular components mediate interactions with phagocytes that favor bacterial survival. Vaccination approaches targeting the mycobacterial capsule have proven successful in controlling bacterial replication. Although the Mtb capsule is composed of polysaccharides of relatively low complexity, the concept of antigenic variability associated with this structure has been suggested by some studies. Understanding how Mtb shapes its envelope during its life cycle is key to developing anti-infective strategies targeting this structure at the host–pathogen interface.

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Lipoarabinomannan Localization and Abundance during Growth of Mycobacterium smegmatis

et al. 2011

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Lipoarabinomannan (LAM) is a structurally heterogeneous amphipathic lipoglycan present in Mycobacterium spp. and other actinomycetes, which constitutes a major component of the cell wall and exhibits a wide spectrum of immunomodulatory effects. Analysis of Mycobacterium smegmatis subcellular fractions and spheroplasts showed that LAM and lipomannan (LM) were primarily found in a cell wall-enriched subcellular fraction and correlated with the presence (or absence) of the mycolic acids in spheroplast preparations, suggesting that LAM and LM are primarily associated with the putative outer membrane of mycobacteria. During the course of these studies significant changes in the LAM/LM content of the cell wall were noted relative to the age of the culture. The LAM content of the M. smegmatis cell wall was dramatically reduced as the bacilli approached stationary phase, whereas LM, mycolic acid, and arabinogalactan content appeared to be unchanged. In addition, cell morphology and acid-fast staining characteristics showed variations with growth phase of the bacteria. In the logarithmic phase, the bacteria were found to be classic rod-shaped acid-fast bacilli, while in the stationary phase M. smegmatis lost the characteristic rod shape and developed a punctate acid-fast staining pattern with carbolfuchsin. The number of viable bacteria was independent of LAM content and phenotype. Taken together, the results presented here suggest that LAM is primarily localized with the mycolic acids in the cell wall and that the cellular concentration of LAM in M. smegmatis is selectively modulated with the growth phase.

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Biochemical and cultural analysis of mycobacterial recombinants obtained by spheroplast fusion

Cited by 3 publications

References 12 publications

IgA and IgG against Mycobacterium tuberculosis Rv2031 discriminate between pulmonary tuberculosis patients, Mycobacterium tuberculosis-infected and non-infected individuals

IgA and IgG against Mycobacterium tuberculosis Rv2031 discriminate between pulmonary tuberculosis patients, Mycobacterium tuberculosis-infected and non-infected individuals

TheMycobacterium tuberculosiscapsule: a cell structure with key implications in pathogenesis

Lipoarabinomannan Localization and Abundance during Growth of Mycobacterium smegmatis

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