Interaction of phagocytes with filamentous fungi.
Phagocytosis of conidia by macrophages and destruction of hyphae by neutrophils are key processes in the defense against infections caused by filamentous fungi. Impairment in phagocytic function leads to increased susceptibility for an infection with Aspergillus species. The fact that a Th1-based immune response to an infection with Aspergillus species results in an improved prognosis for survival underlines the importance of the phagocytic response. Recognition of conidia by macrophages occurs after shedding of the hydrophobic rodlet layer during swelling and germination. Whereas Aspergillus conidia are killed by various immune effector cells, hyphae are in particular targeted and killed by neutrophils. Moreover, both conidia and hyphae are trapped in neutrophil extracellular traps (NETs) that form a containment to localize the infection and to prevent systemic spreading of the fungus in the host. In addition, A. fumigatus interferes with the innate immunity, with both the complement system and defense mechanisms of phagocytes, thereby evading at least in part the innate immune system.
Brakhage
Axel A
AA
Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute (HKI), Beutenbergstrasse 11a, 07745 Jena, Germany. Axel.Brakhage@hki-jena.de
Bruns
Sandra
S
Thywissen
Andreas
A
Zipfel
Peter F
PF
Behnsen
Judith
J
D000818:Animals; D001228:Aspergillosis / Q000276:immunology*; D001230:Aspergillus / Q000276:immunology*; D003713:Dendritic Cells / Q000276:immunology; D054884:Host-Pathogen Interactions / Q000276:immunology*; D006801:Humans; D025301:Hyphae / Q000276:immunology; D007113:Immunity, Innate; D008264:Macrophages / Q000276:immunology / Q000382:microbiology; D009504:Neutrophils / Q000276:immunology / Q000382:microbiology; D010586:Phagocytes / Q000276:immunology / Q000382:microbiology*; D010587:Phagocytosis; D013172:Spores, Fungal / Q000276:immunology