C. Albicans Biofilm Formation is Restricted by Periodontal Ligament Cells and Induces Differential Cytokines Response Compared to Planktonic C. Albicans

Candida albicans is the most numerous commensal and potentially pathological yeast in the human oral cavity. Here we investigate the ability of C. albicans to form a biofilm on human root tip surfaces (RTs) in the presence of periodontal ligament (PDL) cells, and we compare the expression of cytokines in PDL cells induced by biofilm on RTs compared to that induced by planktonic C. albicans. PDL cells were added at the adhesion phase of C. albicans, or after C. albicans cells were allowed to attach to RTs for 90 minutes. The whole mixed culture was allowed to form a biofilm. Development of a biofilm on RTs was analyzed after 24 h using the XTT reduction assay and by scanning electron microscopy. To analyze cytokine expression by real-time PCR at two and three hours, biofilms formed on RTs or planktonic C. albicans were co-cultured with PDL cells. Our results show that PDL cells limit biofilm formation, especially when co-cultured before the attachment phase. Biofilms induced a more persistent expression of IL-1 β and RANKL in PDL cells than did planktonic C. albicans. IL-10 expression in PDL cells was down regulated in response to biofilms or planktonic C. albicans as compared with controls.