Department of Virology, Haartman Institute, University of Helsinki, Helsinki, Finland.
PLoS One. 2012;7(8):e42376. doi: 10.1371/journal.pone.0042376. Epub 2012 Aug 3.
Biotin is an essential vitamin that binds streptavidin or avidin with high affinity and specificity. As biotin is a small molecule that can be linked to proteins without affecting their biological activity, biotinylation is applied widely in biochemical assays. In our laboratory, IgM enzyme immuno assays (EIAs) of µ-capture format have been set up against many viruses, using as antigen biotinylated virus like particles (VLPs) detected by horseradish peroxidase-conjugated streptavidin. We recently encountered one serum sample reacting with the biotinylated VLP but not with the unbiotinylated one, suggesting in human sera the occurrence of biotin-reactive antibodies. In the present study, we search the general population (612 serum samples from adults and 678 from children) for IgM antibodies reactive with biotin and develop an indirect EIA for quantification of their levels and assessment of their seroprevalence. These IgM antibodies were present in 3% adults regardless of age, but were rarely found in children. The adverse effects of the biotin IgM on biotinylation-based immunoassays were assessed, including four inhouse and one commercial virus IgM EIAs, showing that biotin IgM do cause false positivities. The biotin can not bind IgM and streptavidin or avidin simultaneously, suggesting that these biotin-interactive compounds compete for the common binding site. In competitive inhibition assays, the affinities of biotin IgM antibodies ranged from 2.1 × 10(-3) to 1.7 × 10(-4 )mol/L. This is the first report on biotin antibodies found in humans, providing new information on biotinylation-based immunoassays as well as new insights into the biomedical effects of vitamins.
生物素是一种必需的维生素，它能与链霉亲和素或亲和素以高亲和力和特异性结合。由于生物素是一种小分子，可以与蛋白质连接而不影响其生物活性，因此生物素化被广泛应用于生化分析中。在我们的实验室中，已经建立了针对多种病毒的 µ-捕获格式 IgM 酶免疫分析（EIAs），使用生物素化病毒样颗粒（VLPs）作为抗原，这些 VLPs 可以被辣根过氧化物酶缀合的链霉亲和素检测到。我们最近遇到了一个与生物素化 VLP 反应但与非生物素化 VLP 不反应的血清样本，提示在人类血清中存在生物素反应性抗体。在本研究中，我们在普通人群（成人 612 份血清样本和儿童 678 份血清样本）中搜索与生物素反应的 IgM 抗体，并开发了一种间接 EIA 来定量检测其水平和评估其血清流行率。这些 IgM 抗体在 3%的成年人中存在，与年龄无关，但在儿童中很少发现。我们评估了生物素 IgM 对基于生物素化的免疫分析的不良影响，包括四种内部和一种商业病毒 IgM EIA，结果表明生物素 IgM 确实会导致假阳性。生物素不能同时与 IgM 和链霉亲和素或亲和素结合，这表明这些与生物素相互作用的化合物竞争共同的结合位点。在竞争性抑制试验中，生物素 IgM 抗体的亲和力范围为 2.1×10(-3) 至 1.7×10(-4)mol/L。这是首次在人类中发现生物素抗体的报道，为基于生物素化的免疫分析提供了新的信息，也为维生素的生物医学效应提供了新的见解。
