Abstract: Objective To investigate the effects of imiquimod on cytokine secretions of normal human epidermal Langerhans cells (LCs) and HaCaT cells, and to better understand the mechanism of immune regulation by imiquimod. Methods LCs were sorted from prepared epidenmal cells by density gradient centrifugation and magnetic-activated cell sorting (MACS). LCs and HaCaT cells were cultured in media with or without 5 μg/mL of imiquimod for 4 hours, then cell-free culture supernatants were harvested, cytokines were detected by ELISA kits. Results TNF-α, IL-1β and IL-6 secreted from imiquimod treated LCs were all higher than those from control LCs (all P<0.05), but there is no statistical difference between the cytokines from imiquimod treated HaCaT cells and those from control HaCaT cells. Conclusion Imiquimod can upregulate the secretions of cytokines from human epidermal LCs but not from HaCaT cells.

Key words: Imiquimod, Langerhans cells, Keratinoeytes, Cytokines