Induction of antigen specific peripheral tolerance by targeting Langerhans cells

光疗通常能诱导银屑病患者较长的缓解期，这不能简单地用紫外线诱导的细胞凋亡来解释。因此，还应考虑调节性T细胞的作用。我们最近报道了窄带UVB通过诱导调节性T细胞的产生来抑制延迟型超敏反应（DTH）和接触性超敏反应。然而，诱导调节性T细胞进入DTH的紫外线波长尚不清楚。我们使用单色仪照射小鼠DTH模型，产生几种UVB波长（290 nm, 300 nm， 310 nm和320 nm）。所有波长都能显著抑制潜点，其中300 nm波长抑制最大。采用实时聚合酶链反应（mRNA）和FACS分析（蛋白）分析耐受小鼠淋巴结细胞中Foxp3的表达。在300 nm处Foxp3的诱导量增加了2倍。同样，在300 nm处，白细胞介素(IL)-10的诱导增加了10倍。相反，IL-17、IL-23和IL-12在300 nm处分别被抑制40%、25%和30%。这些数据表明，300 nm紫外光诱导表达foxp3的调节性T细胞，抑制Th-17细胞。除了诱导表达foxp3的调节性T细胞外，Th-17细胞的抑制可能对紫外光诱导的免疫抑制起重要作用。在UVB范围内使用特定波长是一种诱导抗原特异性外周耐受的新策略，并为过敏性皮肤病提供了新的潜在治疗方法。

Phototherapy generally induces a relatively long remission period in patients with psoriasis, which cannot be explained simply by UV-induced apoptosis. Therefore, the role of regulatory T cells should also be considered. We recently reported that narrow-band UVB suppresses delayed-type hypersensitivity (DTH) and contact hypersensitivity by inducing regulatory T cell production. The UV wavelength that induced regulatory T cells to DTH, however, was not known. We irradiated a mouse DTH model using a monochromator to produce several UVB wavelengths (290 nm, 300 nm, 310 nm, and 320 nm). All wavelengths tested significantly suppressed DTH, with 300 nm inducing maximal suppression. Foxp3 expression in lymph node cells from tolerant mice was analyzed by real time polymerase chain reaction (mRNA) and FACS analysis (protein). Foxp3 induction was increased 2-fold at 300 nm compared with controls. Similarly, interleukin (IL)-10 induction was increased 10-fold at 300 nm. Conversely, IL-17, IL-23, and IL-12 were suppressed by 40%, 25%, and 30%, respectively, at 300 nm. These data indicate that 300-nm UV light induces Foxp3-expressing regulatory T cells and suppresses Th-17 cells. Besides inducing Foxp3-expressing regulatory T cells, the suppression of Th-17 cells might be important for the UV light-induced immune suppression. The use of a specific wavelength within the UVB range is a new strategy for the induction of antigen-specific peripheral tolerance and provides a new potential treatment for allergic dermatologic diseases.