Innate Immunity against Cryptococcus, from Recognition to Elimination

Date
2018-03-07
Authors
Campuzano, Althea
Wormley, Floyd L.
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Abstract

Cryptococcus species, the etiological agents of cryptococcosis, are encapsulated fungal yeasts that predominantly cause disease in immunocompromised individuals, and are responsible for 15% of AIDS-related deaths worldwide. Exposure follows the inhalation of the yeast into the lung alveoli, making it incumbent upon the pattern recognition receptors (PRRs) of pulmonary phagocytes to recognize highly conserved pathogen-associated molecular patterns (PAMPS) of fungi. The main challenges impeding the ability of pulmonary phagocytes to effectively recognize Cryptococcus include the presence of the yeast's large polysaccharide capsule, as well as other cryptococcal virulence factors that mask fungal PAMPs and help Cryptococcus evade detection and subsequent activation of the immune system. This review will highlight key phagocyte cell populations and the arsenal of PRRs present on these cells, such as the Toll-like receptors (TLRs), C-type lectin receptors, NOD-like receptors (NLRs), and soluble receptors. Additionally, we will highlight critical cryptococcal PAMPs involved in the recognition of Cryptococcus. The question remains as to which PRR–ligand interaction is necessary for the recognition, phagocytosis, and subsequent killing of Cryptococcus.

Description
Keywords
Cryptococcus neoformans, Cryptococcus gattii, Cryptococcus deneoformans, host–pathogen interactions, pattern recognition receptors (PRRs), innate immune response, pathogen-associated molecular patterns (PAMPs), C-type lectin receptors (CLRs), Toll-like receptors (TLRs), NOD-like receptors (NLRs)
Citation
Journal of Fungi 4 (1): 33 (2018)
Department
Molecular Microbiology and Immunology