Abstract: Objective To investigate the influences of UVA on the secretion and expression of chemokine CXCL11/I-TAC by HaCaT cells induced by interferon γ （IFN-γ） and tumor necrosis factor α （TNF-α）. Methods HaCaT cells were cultured in the presence of IFN-γ and TNF-α and irradiated with UVA of 2, 4 and 8 J/cm2, respectively; those cells receiving neither treatment with IFN-γ or TNF-α nor UVA irradiation served as the negative control, and those receiving only cytokine treatment but no irradiation as the positive control. After another 24-hour culture, enzyme-linked immunosorbent assay （ELISA） was performed to detect the protein levels of CXCL11/I-TAC in the supernatant of HaCaT cells, real time PCR to measure the mRNA expression of CXCL11/I-TAC in these HaCaT cells. Results As far as the negative control HaCaT cells were concerned, there was a minor secretion of CXCL11/I-TAC protein and expression of CXCL11/I-TAC mRNA. After treatment with IFN-γ and TNF-α of 10 μg/L, the protein and mRNA expressions of CXCL11/I-TAC were synergistically upregulated, whereas the induced secretion and expression of CXCL11/I-TAC by HaCaT cells were dose-dependently inhibited by UVA irradiation. Conclusions UVA irradiation inhibits the secretion and expression of CXCL11/I-TAC by HaCaT cells, which in turn suppresses the chemotaxis of Th1/Tc1 cells in some degree.

Key words: Ultraviolet