PDF(Pubmed)
Abstract：
In the United States, 19 allergen extracts of different specificities are standardized, which means that their potencies are determined in comparison to a US reference standard. For cat allergen extracts, potency is determined by measuring Fel d 1 content expressed in in Fel d 1 units, and with a unitage that correlates with skin test reactions (bioequivalent allergy units or BAU). Currently, Fel d 1 content is measured with a radial immunodiffusion (RID) assay that uses polyclonal sheep antisera to detect the allergenic protein by producing a white precipitin line in agar gel. However, the RID is considered cumbersome, and the polyclonal sera may qualitatively vary among animals and may recognize epitopes irrelevant to human allergic disease. In this report, we describe a quantitative two-site immunoenzymetric assay (IEMA) for Fel d 1 that uses immobilized capture and soluble biotin-labeled detection Fel d 1-specific human IgE monoclonal antibodies (mAb) that have been class-switched to IgG4. Together, they sandwich Fel d 1 molecules from extracts. Using purified natural Fel d 1 as a calibrator, the historically reported ∼4 micrograms Fel d 1/Fel d 1 unit assignment was directly measured in this mAb-based IEMA at 3.12 ± 0.24 micrograms of Fel d 1 per Fel d 1 unit. This IEMA appears to be equivalent to RID in the measurement of biological potencies of commercial cat hair and cat pelt extracts marketed in the United States.
摘要：
在美国,标准化了19种不同特异性的过敏原提取物，这意味着它们的效力是与美国参考标准相比确定的。对于猫过敏原提取物，通过测量以Feld1单位表示的Feld1含量来确定效力，并且具有与皮肤测试反应相关的单位（生物等效过敏单位或BAU）。目前,Feld1含量是通过放射免疫扩散（RID）测定法测量的，该测定法使用多克隆绵羊抗血清通过在琼脂凝胶中产生白色沉淀线来检测变应原蛋白。然而,RID被认为是繁琐的，多克隆血清可能在动物之间存在定性差异，并且可能识别与人类过敏性疾病无关的表位。在这份报告中,我们描述了Feld1的定量双位点免疫酶测定(IEMA),该方法使用固定化捕获和可溶性生物素标记的检测Feld1特异性人IgE单克隆抗体(mAb),这些抗体已类别转换为IgG4.一起,他们从提取物中夹入Feld1分子。使用纯化的天然Feld1作为校准器，历史报道的4微克Feld1/Feld1单位分配在这个基于mAb的IEMA中直接测量，每个Feld1单位为3.12±0.24微克Feld1。在美国销售的商业猫毛和猫皮提取物的生物效力的测量中,该IEMA似乎等同于RID。
