Culture filtrates and whole heat-killed Candida albicans stimulate human monocytes to release interleukin-6.
The release of interleukin-6 (IL-6) by human monocytes upon stimulation with culture filtrates and heat-killed Candida albicans cells was studied. Two strains of C. albicans (a wild strain CA3 and an agerminative mutant CA2) were cultured overnight at 28 degrees C in complete medium, and 10(6) cells/ml were either filtered at different time points (6, 12, 18, 24, 30 hours) or heat-killed. C. albicans preparations were then added to monolayers of monocytes isolated from healthy donors and incubated at 37 degrees C in 5% CO2 atmosphere. Cell culture supernatants were collected at different time points (every 6 hrs for 30 hrs), and IL-6 content was then measured by immunometric assay. Monocytes stimulated with heat-killed C. albicans cells released IL-6 in the supernatants with values ranging from 59 to 460 pg/ml, that peaked at 24 hrs of incubation. Using heat-killed whole cells of C. albicans no major differences were observed between the two strains used in their capacity to induce IL-6. Culture filtrates also stimulated monocytes to release IL-6 and maximal cytokine levels were observed when the monocytes were triggered with filtrates from yeasts cultured for 24 hours. CA2 filtrate induced IL-6 levels to an extent significantly higher than did CA3 filtrate. These data add further evidence to the immunomodulatory properties possessed by structures of C. albicans.
Raponi
G
G
Chair of Clinical Microbiology I, Faculty of Medicine, La Sapienza University of Rome, Italy.
Ghezzi
M C
MC
Mancini
C
C
Filadoro
F
F
D002176:Candida albicans / Q000276:immunology*; D002478:Cells, Cultured; D017077:Culture Media, Conditioned; D006358:Hot Temperature; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism*; D009000:Monocytes / Q000276:immunology* / Q000382:microbiology
D017077:Culture Media, Conditioned; D015850:Interleukin-6