The role of serotonin in antifungal host defense

Unterdorfer,1 H. Niederegger,2 M.P. Dierich1 and C. Lass-Floerl1

Author address: 

1Hygiene, Microbiology and Social Medicine, Medical University Innsbruck, Innsbruck, Austria and 2Section for Experimental Pathophysiology and Immunology, Medical University Innsbruck, Innsbruck, Austria


Serotonin (5-hydroxytryptamine, 5-HT) shows antifungal activity against Aspergillus spp. and Candida spp. in vitro. To determine the mode of action, the extra- or intracellular 5-HT accumulation and possible cell membrane damage in Aspergillus hyphae were investigated. Clinical isolates of A. fumigatus (n = 1) and A. flavus (n = 2) were examined. Detection of 5-HT was performed using indirect immunofluorescence (IF) staining and laser scanning confocal microscopy (LSCM). 5-HT concentrations from 3.7 lmol L-1 to 235 mmol L-1 were used and incubated for 30, 60 and 90 min as well as for 6 and 12 h. Detection was performed using an unlabelled primary and a FITC conjugated secondary antibody. To clarify possible cell membrane damage caused by 5-HT, a double staining method with propidium iodide (PI) and fluorescin diacetate (FDA) was used. IF and LSCM showed specific fluorescent signals in the cytoplasm of 5- HT sensitive hyphae after 30 min of incubation for all tested 5-HT concentrations. Likewise PI/FDA displayed 5-HT concentration dependent impairment of Aspergillus membranes. 5-HT is stored in dense granules of platelets at 65 mmol L-1 and shows antifungal activity. Therefore the role of platelets in defense against Aspergillus spp. needs to be further investigated.

abstract No: 


Full conference title: 

2nd Trends in Medical Mycology
    • TIMM 2nd (2010)