DEVELOPMENT OF AN IN VITRO MODEL FOR PREDICTING THE CONTACT SENSITIVITY TO OCCUPATIONAL CHEMICALS

接触性致敏剂被认为是一种以Th1型辅助细胞活化为特征的免疫反应，而白介素2(IL-2)是Th1细胞分泌的一种具有代表性的细胞因子。本研究通过半抗原刺激接触致敏小鼠的淋巴细胞体外产生IL-2来评价DNCB对DNCB的接触敏感性以及DNBS与DNCB的交叉敏感性。用四甲基偶氮唑盐比色法测定培养上清液中IL-2活性，以其刺激依赖IL-2的CTLL-2细胞生长的能力作为刺激指标。本研究发现：(1)半抗原形式的DNCB在体外可诱导DNCB致敏小鼠淋巴结细胞产生半抗原特异性IL-2；(2)DNCB刺激的体外IL-2产生在体内接触致敏后第7天达到最大；(3)DNCB与DNBS在体外产生IL-2存在交叉反应；(4)DNCB体外产生IL-2与DNBS的交叉反应呈剂量-反应关系。DNCB体外诱导的IL-2产生与DNCB诱导的体内接触性超敏反应以及DNBS诱导的体外IL-2产生与体内接触性超敏反应之间具有良好的相关性。因此，本研究提示半抗原体外诱导小鼠淋巴结细胞产生IL-2可能是预测化学物质接触敏感性及其交叉敏感性的一种新的体外模型。

Contact sensitizers are considered to lead to an immune response characteristic of Th1-type helper cells activation, and interleukin-2 (IL-2) is a representative cytokine secreted by Th1 cells. In this study, contact sensitivity to DNCB and the cross-sensitivity of DNBS with DNCB were evaluated using hapten-stimulated in vitro IL-2 production by the lymph node cells from mice contact sensitized with DNCB.For induction of in vitro IL-2 production, the lymph node cells from sensitized or control mice were cultured with the indicated concentrations of hapten. IL-2 activity in 48 hr culture supernatants was measured by its ability to stimulate IL-2-dependent CTLL-2 cell growths using MTT colorimetric assay and it was expressed as stimulation index. The following facts have emerged from our study.(1)DNCB in the form of hapten can induce hapten-specific in vitro IL-2 production by the lymph node cells from DNCB-sensitized mice.(2)DNCB-stimulated in vitro IL-2 production exhibited a maximal response on the 7th day after in vivo induction of contact sensitization.(3)There was a cross-reaction between DNCB and DNBS in in vitro IL-2 production.(4)DNCB-specific in vitro IL-2 production and the cross-reaction to DNBS showed the strong dose-response relationships.(5)There were goodcorrelations between DNCB-induced in vitro IL-2 production and DNCB-induced in vivo contact hypersensitivity as well as DNBS-induced in vitro IL-2 production and DNBS-elicited in vivo contact hypersensitivity. Thus, the present study suggests that hapten-induced in vitro IL-2 production by the murine lymph node cells may be a new in vitro model for predicting the contact sensitivity and their cross-sensitivity of chemicals.