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Analysis of the Lipid Composition of Mycobacteria by Thin Layer Chromatography
Published on: April 16, 2021
Capsular arabinomannans from Mycobacterium avium with morphotype-specific structural differences but identical
Manon Wittkowski1, Jessica Mittelstädt, Sven Brandau
1Structural Biochemistry, Leibniz-Center for Medicine and Biosciences, Research Center Borstel, D-23845 Borstel, Germany.
The Journal of Biological Chemistry
|April 27, 2007
Summary
Capsular arabinomannans (AMs) from virulent and nonvirulent Mycobacterium avium differ structurally. Acylation, not structure, is key for stimulating immune cells like macrophages and dendritic cells.
Area of Science:
- Immunology
- Microbiology
- Biochemistry
Background:
- Mycobacterium avium exhibits distinct colony morphotypes, including virulent (SmT1) and nonvirulent (SmO) forms.
- The capsule of M. avium contains polysaccharides, specifically arabinomannans (AMs), which may play a role in host-pathogen interactions.
Purpose of the Study:
- To investigate the structural differences of capsular arabinomannans (AMs) between virulent and nonvirulent morphotypes of Mycobacterium avium strain 2151.
- To determine the biological activity of acylated and nonacylated AMs in stimulating immune cells.
Main Methods:
- Separation of acylated and nonacylated polysaccharide fractions from M. avium morphotypes using affinity chromatography.
- Structural characterization of arabinomannans (AMs).
- In vitro incubation of AMs with murine bone marrow-derived macrophages, human dendritic cells, and human peripheral blood mononuclear cells to assess cytokine production and anti-tumor cytotoxicity.
Main Results:
- Arabinomannans (AMs) from the virulent morphotype had longer mannan chains and shorter arabinan chains compared to the nonvirulent morphotype.
- Acylated polysaccharide fractions potently induced tumor necrosis factor-alpha, interleukin-12, and interleukin-10 in macrophages and dendritic cells.
- Both acylated and nonacylated AMs induced anti-tumor cytotoxicity in human peripheral blood mononuclear cells, but acylation was essential for potent immune cell stimulation.
Conclusions:
- Structural variations in capsular AMs between M. avium morphotypes do not correlate with their ability to stimulate macrophages and dendritic cells.
- Acylation of capsular AMs is a critical factor for effective stimulation of murine macrophages and human dendritic cells by Mycobacterium avium.
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