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Updated: Mar 22, 2026
Passive Administration of Monoclonal Antibodies Against H. capsulatum and Others Fungal Pathogens
Published on: February 14, 2011
Trimming Surface Sugars Protects Histoplasma from Immune Attack
1Aberdeen Fungal Group, MRC Centre for Medical Mycology, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom gordon.brown@abdn.ac.uk.
Abstract:
Dectin-1 is an essential innate immune receptor that recognizes β-glucans in fungal cell walls. Its importance is underscored by the mechanisms that fungal pathogens have evolved to avoid detection by this receptor. One such pathogen is Histoplasma capsulatum, and in a recent article in mBio, Rappleye's group presented data showing that yeasts of this organism secrete a β-glucanase, Eng1, which acts to prune β-glucans that are exposed on the fungal cell surface [A. L. Garfoot et al., mBio 7(2):e01388-15, 2016, http://dx.doi.org/10.1128/mBio.01388-15]. The trimming of these sugars reduces immune recognition through Dectin-1 and subsequent inflammatory responses, enhancing the pathogenesis of H. capsulatum.
Insights
Histoplasma capsulatum yeasts secrete Eng1, a β-glucanase that modifies fungal cell wall sugars. This evasion strategy reduces Dectin-1 immune recognition, aiding pathogen survival.
Area of Science:
- Immunology
- Microbiology
- Biochemistry
Background:
- Dectin-1 is a key innate immune receptor recognizing fungal β-glucans.
- Fungal pathogens have evolved mechanisms to evade Dectin-1-mediated immune detection.
- Histoplasma capsulatum is an important fungal pathogen requiring immune evasion strategies.
Purpose of the Study:
- To investigate the mechanisms employed by Histoplasma capsulatum to evade Dectin-1 recognition.
- To identify specific fungal factors involved in immune evasion.
Main Methods:
- Analysis of secreted fungal enzymes.
- Characterization of cell wall component modifications.
- Assessment of immune receptor interaction with fungal surface.
Main Results:
- Histoplasma capsulatum yeasts secrete a β-glucanase enzyme named Eng1.
- Eng1 acts to prune exposed β-glucans on the yeast cell surface.
- This modification reduces recognition by the Dectin-1 immune receptor.
Conclusions:
- The secretion of Eng1 is a novel immune evasion mechanism used by Histoplasma capsulatum.
- By trimming β-glucans, Eng1 diminishes Dectin-1-mediated inflammatory responses.
- This process enhances the pathogenesis and survival of Histoplasma capsulatum.
