Loveless Scott E, Ladics Gregory S, Smith Charlene, Holsapple Michael P, Woolhiser Michael R, White Kimber L, Musgrove D L, Smialowicz Ralph J, Williams W
DuPont Haskell Laboratory for Health and Environmental Sciences, Newark, Delaware 19714, USA.
J Immunotoxicol. 2007 Jul;4(3):233-8. doi: 10.1080/15476910701385687.
EPA guidelines provide a choice in evaluating humoral immune system function in rats and mice immunized with sheep red blood cells (sRBC): an antibody-forming cell (AFC) assay or a sRBC-specific serum IgM enzyme-linked immunosorbent assay (ELISA). Four different laboratories used both methods to detect suppression of the antibody response by cyclophosphamide (CP) or dexamethasone (DEX). Attempts were made to minimize interlaboratory variability through the use of common reagents and vendors; each laboratory used the same source for rodents, immunosuppressive agents, and one sheep for sRBCs, and determined optimal sRBC concentration for immunization and peak day of antibody response in female CD rats and CD1 mice. The CP dose at which statistical significance was first observed in each species was quite similar within each lab using either assay. For DEX, the AFC assay detected significant and greater suppression at lower concentrations compared to the ELISA in both rats and mice. All labs detected DEX suppression using an AFC assay, whereas only one lab detected significant suppression in both species using an ELISA. For both compounds the magnitude of suppression was greater using the AFC assay, and resulted in ID(50) values which were lower in the AFC assay when compared to the ELISA. In addition, cross-species comparisons of ID(50) values suggested rats were more sensitive than mice. These initial experiments with two chemicals indicated that the AFC assay is consistently better at identifying suppression of a T-dependent antibody response across laboratories following xenobiotic exposures in outbred rats and mice. Additional compounds will need to be evaluated before concluding that one method is superior or more sensitive to the other in detecting suppression of the antibody response.
美国环境保护局（EPA）的指南为评估用绵羊红细胞（sRBC）免疫的大鼠和小鼠的体液免疫系统功能提供了一种选择：抗体形成细胞（AFC）测定法或sRBC特异性血清IgM酶联免疫吸附测定法（ELISA）。四个不同的实验室使用这两种方法来检测环磷酰胺（CP）或地塞米松（DEX）对抗体反应的抑制作用。通过使用通用试剂和供应商，试图尽量减少实验室间的差异；每个实验室使用相同来源的啮齿动物、免疫抑制剂和一只绵羊提供sRBC，并确定雌性CD大鼠和CD1小鼠免疫的最佳sRBC浓度以及抗体反应的峰值日。在每个实验室中，使用任何一种测定法，在每个物种中首次观察到统计学显著性的CP剂量都非常相似。对于DEX，与ELISA相比，AFC测定法在较低浓度下检测到显著且更强的抑制作用，在大鼠和小鼠中均如此。所有实验室使用AFC测定法都检测到了DEX的抑制作用，而只有一个实验室使用ELISA在两个物种中都检测到了显著抑制作用。对于这两种化合物，使用AFC测定法时抑制程度更大，并且与ELISA相比，AFC测定法的半数抑制剂量（ID(50)）值更低。此外，ID(50)值的跨物种比较表明大鼠比小鼠更敏感。这两种化学物质的初步实验表明，在检测远交系大鼠和小鼠经外源化合物暴露后抗体反应的抑制方面，AFC测定法在不同实验室之间始终能更好地识别对T细胞依赖性抗体反应的抑制。在得出一种方法在检测抗体反应抑制方面优于另一种方法或比另一种方法更敏感的结论之前，还需要评估其他化合物。
