Objective: Although oral fibroblasts are thought to have the potential to enhance host defenses against Candida albicans , it is unknown whether they are able to recognize Candida cell components to increase the expression of antifungal peptides, such as defensin factors, against Candida infection.
Methodology: We performed expression profiles of defensin genes induced by heat-killed C. albicans in oral immortalized fibroblasts (GT1) using cDNA microarray analysis. From those results, quantitative RT-PCR was used to examine the effects of Candida β-glucan-containing particles (β-GPs) on β-Defensin 118 (DEFB 118) expression in oral mucosal cells. Furthermore, the antifungal activities of recombinant DEFB 118 against C. albicans and C. glabrata were investigated using fungicidal assays.
Results: Microarray analysis showed that DEFB118, β-Defensin 129 (DEFB129), and α-Defensin 1 (DEFA1) genes were induced by heat-killed C. albicans and that their mRNA expressions were also significantly increased by live as well as heat-killed C. albicans . Next, we focused on DEFB118, and found that GT1, primary fibroblasts, and RT7 (oral immortalized keratinocytes) constitutively expressed DEFB118 mRNA expression in RT-PCR. Furthermore, C. albicans β-GPs significantly increased the expression of DEFB118 mRNA in GT1 and primary fibroblasts. Although DEFB118 mRNA expression in RT7 was significantly induced by both live and heat-killed C. albicans, C. albicans β-GPs failed to have an effect on that expression. Finally, recombinant DEFB118 significantly decreased the survival of both strains of C. albicans in a dose-dependent manner, whereas no effects were seen for both C. glabrata strains.
Conclusion: DEFB118, induced by C. albicans β-GPs from oral fibroblasts, may play an important role in oral immune responses against C. albicans infection.