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Updated: Nov 12, 2025
08:08
Automated Measurement of Cryptococcal Species Polysaccharide Capsule and Cell Body
Published on: January 11, 2018
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Cryptococcus gattii evades CD11b-mediated fungal recognition by coating itself with capsular polysaccharides
Keigo Ueno1, Yoshiko Otani1,2, Nao Yanagihara1,2
1Department of Chemotherapy and Mycoses, National Institute of Infectious Diseases, Shinjuku-ku, Tokyo, Japan.
European Journal of Immunology
|March 17, 2021
Summary
Capsular polysaccharides (CPs) from Cryptococcus gattii are crucial for fungal virulence and immune evasion. Deleting CAP genes eliminates the capsule, reducing pathogenicity and increasing susceptibility to host defenses.
Area of Science:
- Medical Mycology
- Immunology
- Molecular Biology
Background:
- Cryptococcus gattii causes life-threatening cryptococcosis.
- The role of capsular polysaccharides (CPs) in C. gattii virulence and immune evasion is not fully understood.
Purpose of the Study:
- To investigate the role of C. gattii CPs in pathogenicity.
- To elucidate the mechanisms by which CPs contribute to immune evasion.
Main Methods:
- Generation of a CAP gene deletant strain of C. gattii.
- In vitro assessment of virulence and susceptibility to host-related factors.
- Analysis of extracellular CPs' interaction with acapsular strains and immune cells (dendritic cells).
- Investigation of immune cell recognition pathways involving CD11b and Syk.
Main Results:
- The CAP gene deletant completely lacked capsule and virulence, showing increased susceptibility to oxidative, hypoxic, and hypotrophic conditions.
- Extracellular CPs specifically bound to acapsular C. gattii strains, conferring immune escape properties.
- Dendritic cells showed reduced uptake and stimulation by CP-treated acapsular strains.
- CPs block the interaction between dendritic cell receptor CD11b and C. gattii cells, hindering immune recognition.
Conclusions:
- CPs are essential virulence factors for C. gattii.
- CPs facilitate immune evasion by coating fungal antigens and inhibiting immune cell recognition via the CD11b pathway.
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