Broad-Specificity Immunoassays for Sulfonamide Detection: Immunochemical Strategy for Generic Antibodies and Competitors
作者:Milan Franek、Iva Diblikova、Ivo Cernoch、Maria Vass、Karel Hruska
DOI:10.1021/ac0514422
日期:2006.3.1
Development of antibodies with broad specificity recognition for sulfonamide drugs was found to be surprisingly difficult when conventional immunochemical strategies were applied to hapten design. To improve the cross-reactivity pattern of antibodies for the family of sulfonamide drugs, a novel strategy based on the single-ring (fragment-derived) hapten moieties with different spacer substituent lengths was employed for the preparation of immunogens, coating conjugates, and enzyme competitors. The rabbit antibodies raised against a common (one-ring) p-aminobenzenesulfonamide hapten moiety (attached to a carrier protein through the N-1 position) in combination with a homologous hapten−peroxidase tracer allowed the detection of 15 sulfonamide species at the maximum residue limit level using direct ELISA. The two-ring 6-(4-aminobenzensulfonylamino)hexanoic hapten mimics, previously reported in the literature as a weak generic antigen, generated surprisingly superior immune responses in rabbits. The antibodies raised against this two-ring hapten were capable of detecting at least 19 and 17 sulfonamides in a direct ELISA system at the regulatory level with sensitivities corresponding to 20 and 50% binding inhibition, respectively. A negligible cross-reaction with N4 metabolites makes it possible to measure responses of parent sulfonamides in the presence of their metabolized forms. In skimmed milk, the highest limit of detection (LOD) for sulfacetamide defined as 20% inhibition was 65.2 μg·L-1 (IC20 value), whereas the additional 18 sulfonamides tested exhibited LODs in the range of 0.2−36.8 μg·L-1. This sensitivity allows simple multisulfonamide tests to be established for use in the laboratory or on site.
开发具有广谱特异性识别磺胺类药物的抗体在应用传统免疫化学策略进行半抗原设计时发现异常困难。为了改善针对磺胺类药物家族的抗体交叉反应模式,采用了基于单环(片段衍生)半抗原母体与不同间隔取代长度的策略来制备免疫原、包被偶联物和酶竞争剂。针对常见(单环)对氨基苯磺酰胺半抗原母体(通过N-1位置连接载体蛋白)以及同源半抗原-过氧化物酶示踪剂,能够利用直接ELISA法检测到15种磺胺类品种在最大残留限量的水平。先前文献报道为弱泛抗原的双环6-(4-氨基苯磺酰氨基)己酸半抗原模拟物,在兔子中引发了显著更优越的免疫反应。针对此双环半抗原产生的抗体能够在一个直接ELISA体系中以对应20%和50%结合抑制的灵敏度分别检测至少19种和17种磺胺类药物。对N4代谢物几乎无交叉反应使得在存在其代谢形式的情况下能够测量母体磺胺类药物的反应。在脱脂牛奶中,以20%抑制定义的最高检测限(LOD),磺胺醋酰为65.2 μg·L-1(IC20值),而另外测试的18种磺胺类药物的LOD范围在0.2−36.8 μg·L-1。这种灵敏度允许在实验室或现场建立简单多磺胺检测。