<i>C. albicans</i> infection of human whole blood results in rapid activation of cellular innate immunity.

<p>(A) Human whole blood was infected with different amounts of <i>C. albicans</i> yeasts for and changes in CD69 surface levels (black open histograms) on immune cells were analyzed. Filled grey histograms indicate basal CD69 expression. The early activation marker CD69 was increased on PMN, monocytes and NK-cells following inoculation of <i>C. albicans</i>. In contrast, no changes in CD69 surface levels could be observed on T-cells and B-cells. Inoculation of whole blood with lower amounts of <i>C. albicans</i> resulted in less efficient immune activation. Data from one of three independent experiments using cells from different donors with virtually identical results are shown. (B) Significantly increased plasma levels of pro-inflammatory cytokines (, IL-6, , ) as well as chemokines (IL-8, ) could be detected after of infection with <i>C. albicans</i> (white bars). Grey bars indicate basal plasma levels in mock-infected samples. Bars show means standard deviation of at least 4 independent experiments with whole blood from different donors, , , . (C) PMN activation is shown (upper panel) and (lower panel) after inoculation of <i>C. albicans</i> into whole blood by detection of intracellular generated reactive oxygen intermediates (oxidation of dihydrorhodamine-123 to rhodamine-123, R-123) and by changes in the surface expression levels of activation markers CD66b, CD11b, CD64 ( receptor I) and CD16 ( receptor III). Grey filled histograms indicate basal expression on PMN from mock-infected samples, black open histograms indicate surface levels following <i>C. albicans</i> inoculation. Data from one of at least three independent experiments with virtually identical results are shown. (D) Plasma samples of whole-blood infection experiments were analyzed for the release of myeloperoxidase, lactoferrin and elastase from neutrophil granules. Grey bars show the basal levels within mock-infected blood, white bars show levels after inoculation with <i>C. albicans</i> (). The release of the three antimicrobial peptides was significantly enhanced after contact to the fungus. Bars show means standard deviation of at least 4 independent experiments with whole blood from different donors, , .