TNF-α Expression in Oral Candida albicans-Infected Human Gingival Epithelial Cells

The presence of yeasts in periodontal pockets is well documented and Candida albicans is the species most commonly isolated from the oral cavity. The immune response and anticandidal activity of oral epithelial cells play a key role in host defense against C. albicans infection. Human gingival epithelial cells were primarily cultured from healthy human gingival tissues and challenged with C. albicans ATCC90029. After 8 hours, total RNA was extracted and mRNA levels were analyzed using Affymetrix GeneChip (Human Genome U133 plus 2.0 Array, ca. 47,000 genes). Numerous genes showed altered gene expression, and among these, a pro-inflammatory cytokine, tumor necrotizing factor alpha (TNF-α), was up-regulated by more than two-fold over normal levels after C. albicans infection. Altered mRNA levels on GeneChip results were confirmed by reverse transcription-polymerase chain reaction (RT-PCR) and real-time RT-PCR. Rat gingiva was infected with C. albicans cells and immunohistochemical examination for TNF-α production was then carried out. Stronger immunoreactivity against TNF-α was observed in rat gingival epithelium infected with C. albicans.