Mechanisms of UV-induced immunosuppression
Mechanisms of UV-induced immunosuppression
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DOI：
10.2302/kjm.54.165
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发表时间：
2005-12-01
影响因子：
2
通讯作者：
Schwarz, Thomas
中科院分区：
文献类型：
--
作者：
Schwarz, Thomas
紫外线辐射（UV），特别是UVB范围，以几种方式抑制免疫系统。UVB抑制抗原呈递，诱导免疫抑制细胞因子的释放，并引起白细胞凋亡。然而，UVB不会引起一般的免疫抑制，而是以抗原特异性的方式抑制免疫反应。将接触性过敏原施用于暴露于紫外线的皮肤上不会引起致敏，但会诱导抗原特异性耐受，因为这样的个体以后不能对同一过敏原致敏，尽管对其他过敏原的致敏性不受损害。这种特异性免疫抑制是由抗原特异性抑制/调节T细胞介导的。UVB诱导的DNA损伤是UV介导的免疫抑制的主要分子触发剂。DNA损伤的减少减轻了UV诱导的免疫抑制。同样，白细胞介素-12具有减少DNA损伤的能力，可以防止紫外线诱导的免疫抑制，甚至破坏耐受性。淋巴结中UV损伤的朗格汉斯细胞呈递抗原似乎是调节性T细胞发育的基本要求。解决紫外线诱导的免疫抑制的分子机制的研究将有助于更好地了解如何紫外线作为一种病原体，但另一方面也可以作为一种治疗工具。
Ultraviolet radiation (UV), in particular the UVB range, suppresses the immune system in several ways. UVB inhibits antigen presentation, induces the release of immunosuppressive cytokines and causes apoptosis of leukocytes. UVB, however, does not cause general immunosuppression but rather inhibits immune reactions in an antigen-specific fashion. Application of contact allergens onto UV-exposed skin does not cause sensitization but induces antigen-specific tolerance since such an individual cannot be sensitized against the very same allergen later, although sensitization against other allergens is not impaired. This specific immunosuppression is mediated by antigen-specific suppressor/regulatory T cells. UVB-induced DNA damage is a major molecular trigger of UV-mediated immunosuppression. Reduction of DNA damage mitigates UV-induced immunosuppression. Likewise interleukin-12 which exhibits the capacity to reduce DNA damage can prevent UV-induced immunosuppression and even break tolerance. Presentation of the antigen by UV-damaged Langerhans cells in the lymph nodes appears to be an essential requirement for the development of regulatory T cells. Studies addressing the molecular mechanisms underlying UV-induced immunosuppression will contribute to a better understanding how UV acts as a pathogen but on the other hand can be also used as a therapeutic tool.