Discipline of Dermatology, Bosch Institute, Sydney Cancer Centre, The University of Sydney, NSW 2006, Australia.
Photochem Photobiol Sci. 2010 Jan;9(1):25-30. doi: 10.1039/b9pp00051h. Epub 2009 Nov 6.
Ultraviolet A (UVA) radiation can have dual affects on the immune system depending on dose. At doses of approximately 1.8 J cm(-2), UVA acts in an immunosuppressive manner, whilst at higher doses UVA can promote recovery and protection against UVB-induced immunosuppression in mice. We utilised a model of contact hypersensitivity (CHS) to investigate how different doses of UVA modulates CD8 T cell immunity against a hapten in vivo. Only 1.8 J cm(-2) UVA decreased the CHS response compared to unirradiated mice, but this did not correlate with an inhibition of primary effector CD8 T cells. A similar expansion of effector CD8 T cells in skin-draining lymph nodes and accumulation of IFN-gamma-producing CD8 T cells in the ear skin was observed between unirradiated and UVA-irradiated mice. However, dermal memory CD8 T cells examined 9 weeks post challenge showed decreased numbers in mice irradiated with 1.8 J cm(-2) UVA compared with unirradiated, 1.3 J cm(-2) and 3.4 J cm(-2) UVA-irradiated mice. Therefore, UVA does not inhibit the expansion, migration or IFN-gamma secretion of CD8 T cells during a primary immune response. However, exposure to immunosuppressive UVA causes a defect in CD8 T cell development that impairs the ability of cells to become long-term memory cells.
紫外线 A（UVA）辐射对免疫系统的影响具有双重性，具体取决于剂量。在约 1.8 J cm(-2) 的剂量下，UVA 具有免疫抑制作用，而在更高的剂量下，UVA 可以促进恢复，并保护小鼠免受 UVB 诱导的免疫抑制。我们利用接触超敏反应（CHS）模型来研究不同剂量的 UVA 如何调节体内针对半抗原的 CD8 T 细胞免疫。只有 1.8 J cm(-2) 的 UVA 照射会降低 CHS 反应，与未照射的小鼠相比，但这与对初始效应 CD8 T 细胞的抑制无关。在未照射和 UVA 照射的小鼠之间，观察到效应 CD8 T 细胞在皮肤引流淋巴结中的类似扩张以及 IFN-γ产生的 CD8 T 细胞在耳部皮肤中的积累。然而，在挑战后 9 周检查真皮记忆 CD8 T 细胞时，与未照射、1.3 J cm(-2) 和 3.4 J cm(-2) UVA 照射的小鼠相比，照射 1.8 J cm(-2) UVA 的小鼠中的数量减少。因此，UVA 在初次免疫反应期间不会抑制 CD8 T 细胞的扩增、迁移或 IFN-γ分泌。然而，暴露于免疫抑制性 UVA 会导致 CD8 T 细胞发育缺陷，从而削弱细胞成为长期记忆细胞的能力。
