Abstract: Objective: To investigate the effect of UVB irradiation on the expression of surface antigens induced by IFN-γ on normal human keratinocytes in vitro. Methods: A routine culture of keratinocytes was established which were pre-incubated with recombinant human IFN-γ, and then, irradiated with UVB. The expression of surface antigens, such as CD40, CD54, MHC-II, was detected by FACS and the level of α-MSH before and after UVB irradiation was detected by RIA. The levels of cytokines, such as IL-6, IL-8 and TNF-α, were detected by ELISA. Results: The levels of surface antigens were low, which significantly increased after stimulated by IFN-γ, after that, markedly decreased after UVB irradiation but the level of α-MSH increased to peak at 72 h after irradiation. The levels of CD54 and IL-8 release expression were increased after treated by sCD40L. Conclusion: UVB irradiation down-regulates the level of surface antigens induced by IFN-γ on keratinocytes, which may be related with α-MSH induced by UVB. 

Key words: keratinocytes, surface antigens, IFN-γ, UVB, α-MSH