Beiersdorf AG, Research and Development, Hamburg, Germany.
PLoS One. 2010 Dec 23;5(12):e15221. doi: 10.1371/journal.pone.0015221.
Photoactivation and binding of photoactive chemicals to proteins is a known prerequisite for the formation of immunogenic photoantigens and the induction of photoallergy. The intensive use of products and the availability of new chemicals, along with an increasing exposure to sun light contribute to the risk of photosensitizing adverse reactions. Dendritic cells (DC) play a pivotal role in the induction of allergic contact dermatitis. Human peripheral blood monocyte derived dendritic cells (PBMDC) were thus perceived as an obvious choice for the development of a novel in vitro photosensitization assay using the modulation of cell surface protein expression in response to photosensitizing agents. In this new protocol, known chemicals with photosensitizing, allergenic or non-allergenic potential were pre-incubated with PBMDCs prior to UVA irradiation (1 J/cm(2)). Following a 48 h incubation, the expression of the cell surface molecules CD86, HLA-DR and CD83 was measured by flow cytometry. All tested photosensitizers induced a significant and dose-dependent increase of CD86 expression after irradiation compared to non-irradiated controls. Moreover, the phototoxicity of the chemicals could also be determined. In contrast, (i) CD86 expression was not affected by the chosen irradiation conditions, (ii) increased CD86 expression induced by allergens was independent of irradiation and (iii) no PBMDC activation was observed with the non-allergenic control. The assay proposed here for the evaluation of the photoallergenic potential of chemicals includes the assessment of their allergenic, phototoxic and toxic potential in a single and robust test system and is filling a gap in the in vitro photoallergenicity test battery.
光激活和光活性化学物质与蛋白质的结合是形成免疫原性光抗原和诱导光过敏的已知前提。产品的大量使用和新化学物质的可用性，以及人们越来越多地暴露在阳光下，增加了光致敏不良反应的风险。树突状细胞（DC）在诱导过敏性接触性皮炎中起着关键作用。因此，人类外周血单核细胞衍生的树突状细胞（PBMDC）被认为是开发使用光致敏剂对细胞表面蛋白表达进行调制的新型体外光致敏测定法的明显选择。在这个新方案中，已知具有光致敏、变应原或非变应原潜力的化学物质在 UVA 照射（1 J/cm(2))之前与 PBMDC 预孵育。孵育 48 小时后，通过流式细胞术测量细胞表面分子 CD86、HLA-DR 和 CD83 的表达。与未照射对照相比，所有测试的光致敏剂在照射后均诱导 CD86 表达显著且剂量依赖性增加。此外，还可以确定化学物质的光毒性。相比之下，（i）选择的照射条件不会影响 CD86 的表达，（ii）变应原诱导的 CD86 表达增加与照射无关，（iii）非变应原对照未观察到 PBMDC 激活。这里提出的用于评估化学物质光变应原潜力的测定法包括在单一稳健的测试系统中评估其变应原性、光毒性和毒性潜力，填补了体外光变应原性测试组中的空白。
