干扰素γ诱导人黑素细胞CD40的表达

CD40 Expression on Melanocytes Induced by IFN-γ and Its Significance

目的探讨γ-干扰素(IFN-γ)体外诱导人黑素细胞表面CD40分子的表达及其意义。方法常规分离培养人黑素细胞,流式细胞仪测定IFN-γ处理前后细胞表面CD40等免疫分子表达;混合淋巴细胞反应评价黑素细胞对同种异体T淋巴细胞的刺激能力;ELISA检测培养上清液IL-8、IL-10、IL-12的浓度。结果体外培养的人黑素细胞表面表达少量CD40分子;不同浓度的IFN-γ处理黑素细胞24h、48h、72h后,能显著促进其CD40的上调(P<0.01),且24h处理组的黑素细胞CD40的表达量和IFN-γ的浓度呈直线相关。经IFN-γ诱导后的黑素细胞形态有所变化,刺激同种异体淋巴细胞的能力也显著增加,300IU/mLIFN-γ处理的黑素细胞72h刺激指数(SI)可达到峰值。黑素细胞经IFN-γ作用后,培养上清液中IL-12水平明显增加(P<0.05),而IL-8、IL-10的浓度无变化(P>0.05)。经IFN-γ预处理的黑素细胞经SCD40L配基化后,能显著上调CD80、细胞间粘附分子1(P<0.01),且这种作用能被特异性的CD40L的单克隆抗体所阻断。结论IFN-γ体外能够诱导黑素细胞功能性地表达CD40分子及增加对淋巴细胞的刺激能力,这对于认识黑素细胞在细胞免疫应答中的作用具有重要的意义,CD40分子上调后,黑素细胞可能不经过CD4+细胞而直接刺激活化CD8+的杀伤性T细胞(CTL)。

Objective To study CD40 expression on melanocytes induced by IFN-?and its significance. Methods CD40 expression was detected by flow cytometry. The capacity of melanocytes to stimulate T lymphocytes was evaluated by mixed ly mphocyte reaction and the supernatant cytokine levels were determined by ELISA. ResultsHuman melanocytes(MC) cultured in vitro expressed low but detectable CD40 surf ace protein. The surface expression of CD40 was markedly up-regulated by stimul ation with interferon(IFN)-?with different concentrations for 24 hours,48 hour s and 72 hours, respectively. The expression of CD40 was correlated with IFN-? levels after 24 hour incubation. MC underwent a morphologic change with an incre ased capacity to stimulate allogenic lymphocytes to proliferate after IFN-?sti mulation. Optimal enhancement of stimulating index(SI) was observed at an IFN-?concentration of 300 IU/ml after 72 hour treatment. Meanwhile concentrations o f interleukin-12 but not interleukin-8 or 10 were obviously increased in the s upernatants of cultured MC. Furthermore, ligation of CD40 via soluble CD40 ligan d(SCD40L) could enhance CD80 and ICAM-1 expression, which could be blocked by s pecific monoclonal antibody to CD40L. Conclusions Since CD40-CD40L is a pair of important and special costimulating signal, it is of great value to elucidate t he fact that CD40 is functionally expressed on MC, thus for a better understandi ng of MC′s role in cellular immune responses. MC might activate cytotoxic T lym phocyte directly and not via CD4 positive lymphocyte.