[Up-to-date findings in the host defence mechanism to cryptococcus infection]

Med Mycol J. 2014;55(3):J107-14. doi: 10.3314/mmj.55.j107.
[Article in Japanese]

Abstract

Cryptococcus neoformans is a medically important opportunistic fungal pathogen with a polysaccharide capsule surrounding the yeast-like cells. In hosts with impaired cell-mediated immunity such as AIDS, uncontrolled infection causes life-threatening meningoencephalitis. In immunocompetent individuals, the host immune response usually limits the growth of the fungal pathogen at the primary infected site, where it may persist, without completely eradicated, in a latent state because of its ability to escape from killing by macrophages. Th1 response in adaptive immunity is essential for the host defense to cryptococcal infection, in which interferon (IFN)-γ polarizes innate macrophages into fungicidal M1 macrophages. Recently, we found that caspase recruitment domain family member (CARD9), an adaptor protein in a signal transduction triggered by C-type lectin receptors, plays a key role in the early production of IFN-γ at the site of infection by recruiting NK cells and CD4(+) and CD8(+) memory-phenotype T cells. We also found that IL-4 produced by Th2 cells stimulates broncoepithelial cells to secrete mucin, which may lead to promotion in the mucociliary clearance of C. neoformans. Here, we summarize the up-to-date findings in the host defense mechanism to this infection with focusing on our recent data.

Publication types

  • Review

MeSH terms

  • Bronchi / cytology
  • Bronchi / metabolism
  • CARD Signaling Adaptor Proteins / physiology
  • CD4-Positive T-Lymphocytes / immunology
  • CD8-Positive T-Lymphocytes / immunology
  • Cryptococcosis / immunology*
  • Cryptococcosis / microbiology*
  • Cryptococcus neoformans* / growth & development
  • Cryptococcus neoformans* / immunology
  • Cryptococcus neoformans* / pathogenicity
  • Epithelial Cells / metabolism
  • Humans
  • Immunity, Cellular
  • Immunocompetence / immunology
  • Immunocompromised Host / immunology
  • Interferon-gamma / physiology
  • Interleukin-4 / physiology
  • Killer Cells, Natural / immunology
  • Lectins, C-Type / physiology
  • Macrophages / immunology
  • Mucins / metabolism
  • Mucociliary Clearance / immunology
  • Th1 Cells / immunology
  • Th2 Cells / immunology

Substances

  • CARD Signaling Adaptor Proteins
  • CARD9 protein, human
  • Lectins, C-Type
  • Mucins
  • Interleukin-4
  • Interferon-gamma