Candida albicans clinical isolates inactivated by formalin with different adherence to buccal epithelial cells induce proinflammatory and regulatory cytokines in human peripheral blood mononuclear cells

Besides the activation of phagocytes, the release of cytokines is the most important immunological defence mechanism of an organism against infection with Candida albicans. On the other hand cytokines induced in the organism by the yeast itself are able to modulate the immune responses of the host. We investigated whether eight clinically isolated strains of C. albicans inactivated by formalin as well as a laboratory strain were able to induce proinflammatory and regulatory cytokines in peripheral blood mononuclear cells (PBMC) of four different donors. Under our assay conditions the yeast strains induced the cytokines interleukin-1 beta (IL-1 beta), interferon-gamma (IFN-gamma) and interleukin-10 (IL-10) in PBMC to varying extents, but not the cytokine interleukin-4 (IL-4). We observed a difference in the reaction of the individual donors to the stimulus C. albicans but on the other hand the extent of the cytokine signal seemed to be dependent on the yeast strain as well. No correlation was found between the ability of the individual C. albicans strains to induce cytokines in PBMC and their ability to adhere to buccal epithelial cells. Determination of the cytokine induction potential of C. albicans strains possibly may contribute to the detection of new virulence factors of this yeast.