Medicinal Safety Research Laboratories, Daiichi Sankyo Co., Ltd., Shizuoka 437-0065, Japan.
J Immunotoxicol. 2013 Jan-Mar;10(1):40-8. doi: 10.3109/1547691X.2012.691122. Epub 2012 Sep 7.
To develop a rat T-cell-dependent antibody response (TDAR) model evaluating both primary and secondary antibody responses, keyhole limpet hemocyanin (KLH) was used to immunize rats twice during a 14-day course of study, a pattern closely linked to that of a short-term general toxicity study. Female rats of four representative strains (e.g., Sprague-Dawley, Wistar, Fischer, and Lewis) were immunized twice with intravenous administrations of KLH (300 µg/rat) on Days 5 and 9 during a 14-day treatment regimen with cyclophosphamide (CPA) at 1, 3, or 6 mg/kg/day. The primary and secondary immunizations of KLH markedly elevated serum anti-KLH IgM and IgG levels in all strains on Days 9 and 15. Remarkable higher levels of anti-KLH IgG (≈ 1000 µg/ml) were noted in all strains, which were more than 4-times compared with those of anti-KLH IgM levels at Day 9, indicating that predominant IgG reactions were induced by the dual immunizations. A large inter-individual variability in KLH-specific IgM and IgG production was observed in all strains. However, levels of the KLH-specific antibodies were considered sufficient for the evaluation, even in Sprague-Dawley and Wistar rats reported as strains with a wide range of variability since immunosuppression of CPA on responses in both anti-KLH IgM and IgG were observed in all strains to the same extent. In addition, the sensitivity of the KLH-ELISA assay system detecting the immunosuppressive effects of CPA was comparable to other assay systems with PFC assay or ELISA using SRBC. The results here demonstrated that these experimental designs could provide valuable information about the influence on both the primary and secondary humoral immune responses in rats when exposed to potential immunomodulatory drugs. Furthermore, the design of the presented TDAR study would support comprehensive evaluation together with the outcome of the conventional general toxicity study.
为了开发一种大鼠 T 细胞依赖性抗体反应（TDAR）模型，以评估初次和再次抗体反应，本文使用钥孔血蓝蛋白（KLH）在 14 天的研究过程中对大鼠进行两次免疫接种，这一模式与短期一般毒性研究非常相似。使用四种代表性品系（如 Sprague-Dawley、Wistar、Fisher 和 Lewis）的雌性大鼠，在环磷酰胺（CPA）1、3 或 6mg/kg/天的 14 天治疗方案中，于第 5 天和第 9 天通过静脉注射 KLH（300μg/大鼠）进行两次免疫接种。KLH 的初次和再次免疫接种在所有品系中均显著提高了血清抗 KLH IgM 和 IgG 水平，分别在第 9 天和第 15 天。所有品系的抗 KLH IgG 水平（≈1000μg/ml）显著升高，比第 9 天的抗 KLH IgM 水平高 4 倍以上，表明双免疫接种诱导了主要的 IgG 反应。在所有品系中，KLH 特异性 IgM 和 IgG 产生均存在较大的个体间变异性。然而，考虑到所有品系的 CPA 对 IgM 和 IgG 反应的免疫抑制作用，KLH 特异性抗体的水平被认为足以进行评估。此外，在报告具有广泛变异性的 Sprague-Dawley 和 Wistar 大鼠中，也观察到 KLH-ELISA 检测 CPA 免疫抑制作用的检测系统的灵敏度与使用 PFC 测定或 ELISA 检测 SRBC 的其他检测系统相当。结果表明，这些实验设计可以为潜在免疫调节药物暴露对大鼠初次和再次体液免疫反应的影响提供有价值的信息。此外，所提出的 TDAR 研究设计将支持与常规一般毒性研究结果一起进行全面评估。
