Kerr S, O'Keeffe G, Kilty C, Doyle S
Biotrin International, The Rise, Mount Merrion, Dublin, Ireland.
J Med Virol. 1999 Feb;57(2):179-85. doi: 10.1002/(sici)1096-9071(199902)57:2<179::aid-jmv16>3.0.co;2-t.
Recombinant versions of parvovirus B19 capsid proteins VP1 and VP2 are used for immunodiagnostic assays for detection of antiviral antibodies. The immune response to B19 is characterized by a gradual loss of antibodies directed against linear epitopes of VP2. A similar occurrence for antibodies raised against VP1 protein would represent a limitation to serological assays incorporating denatured versions of either viral antigen. Four detection systems for B19 Ig detection have been developed, including an IgG enzyme immunoassay (EIA) based on undenatured VP2, an immunofluorescence assay (IFA) based on undenatured VP1, a Western blot assay incorporating denatured VP1 and VP2, and an alternative blot system using denatured VP1 but undenatured VP2. Specimens (n=108) were tested by all four systems and identical results were obtained by EIA, IFA, and alternative blot systems, whereby 75/108 (69%) were B19 IgG-positive. Twelve B19 IgG-positive specimens, representing 16% (12/75) of the confirmed positives, did not react to either viral antigens when tested by Western blot. It is concluded that these sera do not react with linear epitopes of VP1 and VP2 antigens. Eighty-five different specimens, which had previously been shown to be both B19 IgM- and IgG-positive by EIA and IFA, were positive by B19 IgM and IgG Western blot. In the IgG Western blot assay, 69 reacted with both VP1 and VP2 and 16 with VP1 only. It is concluded that there is a requirement for at least one undenatured antigen for the immunological detection of B19 IgG.
细小病毒B19衣壳蛋白VP1和VP2的重组形式用于免疫诊断检测，以检测抗病毒抗体。对B19的免疫反应的特征是针对VP2线性表位的抗体逐渐丧失。针对VP1蛋白产生的抗体出现类似情况，将对包含两种病毒抗原变性形式的血清学检测构成限制。已开发出四种用于检测B19 Ig的检测系统，包括基于未变性VP2的IgG酶免疫测定（EIA）、基于未变性VP1的免疫荧光测定（IFA）、包含变性VP1和VP2的蛋白质印迹测定，以及使用变性VP1但未变性VP2的替代印迹系统。用所有四种系统对108份标本进行检测，EIA、IFA和替代印迹系统获得了相同的结果，其中75/108（69%）为B19 IgG阳性。12份B19 IgG阳性标本，占确诊阳性标本的16%（12/75），在蛋白质印迹检测时对两种病毒抗原均无反应。得出的结论是，这些血清不与VP1和VP2抗原的线性表位反应。85份不同的标本，此前通过EIA和IFA已显示B19 IgM和IgG均为阳性，通过B19 IgM和IgG蛋白质印迹检测也呈阳性。在IgG蛋白质印迹检测中，69份标本与VP1和VP2均反应，16份标本仅与VP1反应。得出的结论是，在免疫检测B19 IgG时需要至少一种未变性抗原。
