Expression of Toll-like Receptor 2 in Cultured Human Keratinocytes: The Effect of Bacterial Antigens, Cytokines and Calcium Concentration

ABSTRACT

BACKGROUND: Toll-like receptors (TLRs) are expressed by human epidermal keratinocytes and are involved in immune responses. OBJECTIVE: The goal of this was to investigate the expression of TLR2 in response to bacterial antigens, cytokines, and different calcium concentrations. METHODS: The expression of TLR2 was assessed after stimulation by lipoteichoic acid (LTA) and streptolysin O (SLO). In addition, TLR2 expression was evaluated after treatment with IFN-gamma and TNF-alpha, and different concentrations of calcium. The expression levels of TLR2 mRNA and protein were studied using RT-PCR and Western blot analysis. RESULTS: Cultured human epidermal keratinocytes constitutively expressed TLR2 and the expression was stimulated by LTA and SLO; in addition, IFN-gamma and TNF-alpha upregulated TLR2 expression. However, the changes in TLR2 expression associated with the calcium concentrations were insignificant. CONCLUSION: TLR2 expression increased with the concentration and duration of bacterial pathogens and this increase was amplified by several cytokines, from activated keratinocytes and other cells.