Choquet-Kastylevsky G, Tedone R, Ducluzeau M T, Kehren J, Nicolas J F, Descotes J
INSERM U503, Toxicologie Médicale et Médecine de l'Environnement, Faculté de Médecine Lyon-RTH Laënnec, 69372, Lyon, France.
Toxicology. 2000 Apr 20;146(1):73-82. doi: 10.1016/s0300-483x(00)00155-4.
The popliteal lymph node (PLN) assay has been proposed to predict the 'autoimmunogenic' potential of xenobiotics. A better understanding of the processes involved in PLN responses is needed to establish the value of this assay for preclinical safety evaluation. In order to determine whether PLN responses involve CD4(+) or CD8(+) T-cells, the effects of streptozotocin (STZ), a prototypic immunotoxic compound, were analyzed after injection into the hind footpad of C57 BL/6 mice and major histocompatibility complex (MHC) class I or II deficient mice. The involvement of type 1 or type 2 cell control on the production of cytokine mRNAs was analyzed in lymph node cells by quantitative RT-PCR, together with the analysis of a wide range of cytokine mRNAs after STZ injection (IL-1alpha, IL-1beta, TNF-alpha, IFN-gamma, IL-2, IL-2 receptor, IL-4, IL-5, IL-6, IL-10 and IL-12). We have found that mice depleted in CD8(+) T-cells did not respond to STZ, whereas mice depleted in CD4(+) T-cells exhibited the expected positive PLN responses, with increased weight and cellularity indices. STZ induced a low production of interleukin (IL)-2 mRNAs, a mild increase in IL-1alpha and IL-6 mRNAs production, and a dramatic increase in IFN-gamma, IL-1beta, TNF-alpha, IL-12 and IL-2 receptor mRNAs, which correlated with positive PLN responses. No effects on IL-4, IL-5 and IL-10 mRNAs synthesis were noted. In CD8(+) T-cell deficient mice, there was no production of IFN-gamma or IL-6 mRNAs. These results suggest that PLN responses to STZ are under the control of type 1, MHC class-I-restricted, CD8(+) T-cells. This is in accordance to the known physiopathology of STZ-induced diabetes. Additional studies are necessary to establish the mechanism of CD8+ T-cell activation.
腘淋巴结（PLN）试验已被用于预测外源性物质的“自身免疫原性”潜力。为了确定该试验在临床前安全性评估中的价值，需要更好地了解PLN反应所涉及的过程。为了确定PLN反应是否涉及CD4(+)或CD8(+) T细胞，将原型免疫毒性化合物链脲佐菌素（STZ）注射到C57 BL/6小鼠以及主要组织相容性复合体（MHC）I类或II类缺陷小鼠的后足垫后，分析了其作用。通过定量逆转录聚合酶链反应（RT-PCR）分析淋巴结细胞中1型或2型细胞控制对细胞因子mRNA产生的影响，并在注射STZ后分析多种细胞因子mRNA（IL-1α、IL-1β、TNF-α、IFN-γ、IL-2、IL-2受体、IL-4、IL-5、IL-6、IL-10和IL-12）。我们发现，CD8(+) T细胞耗竭的小鼠对STZ无反应，而CD4(+) T细胞耗竭的小鼠表现出预期的PLN阳性反应，体重和细胞指数增加。STZ诱导白细胞介素（IL）-2 mRNA产量降低，IL-1α和IL-6 mRNA产量轻度增加，IFN-γ、IL-1β、TNF-α、IL-12和IL-2受体mRNA产量显著增加，这与PLN阳性反应相关。未观察到对IL-4、IL-5和IL-10 mRNA合成的影响。在CD8(+) T细胞缺陷小鼠中，未产生IFN-γ或IL-6 mRNA。这些结果表明，PLN对STZ的反应受1型、MHC I类限制性CD8(+) T细胞的控制。这与STZ诱导糖尿病的已知病理生理学一致。需要进一步研究以确定CD8+ T细胞激活的机制。
