重组N蛋白抗原检测PRRSV抗体ELISA的研究 Ⅱ.试剂盒阴阳性临界值的测定及其与IDEXX公司试剂盒的比较

Development of a Recombinant Nucleoprotein-Based Enzyme-Linked Immunosorbent Assay for Quantification of Antibodies against Porcine Reproductive and Respiratory Syndrome Virus Ⅱ.Performance and optimal cutoff values for the ELISA

对临床上采集的899份猪血清样本,用以纯化的重组N蛋白为包被抗原建立的检测猪繁殖与呼吸综合征病毒(PRRSV)抗体的间接EL ISA进行检测,运用统计学方法摸清了检测结果的分布规律,并和国外IDEXX公司PRRSV抗体检测试剂盒同时对460份血清样本进行检测,结果表明,2种方法的符合率为91.73%。利用TG-ROC软件确定了自制的EL ISA酶标板(NP-EL ISA)的临界值,并标定试剂盒的特异性和敏感性均为92.6%。EL ISA的结果判定标准是:当以血清样本L为标准参考阳性血清时,样品与阳性血清的比值(S/P)小于或等于0.4为阴性;S/P在0.4与0.5之间为可疑;S/P大于或等于0.5为阳性。与IDEXX公司PRRSV抗体检测试剂盒对临床样品的检测结果进行比较后,初步判定所建立的EL ISA之所以出现较多的假阴性,可能是目前临床上出现了PRRSV欧洲型所致。

A rapid, inexpensive enzyme-linked immunosorbent assay （ELISA） for quantitation of antibodies to porcine respiratory and reproductive syndrome virus （PRRSV） in serum was dev.eloped using a recombinant PRRSV nucleoprotein. 460 of 899 serum samples from swines were detected for the antibody to PRRSV by using the developed ELISA and the IDEXX PRRSV antibody test kit simultaneously. The developed ELISA was correlated well （91.72%） with the IDEXX HerdChek ELISA. Performance and optimal cutoff values for the ELISA were determined by using the TwoGraph-ROC functions of the CMDT software package,and it was found that both the specificity and sensitivity of the developed ELISA were 92.7%. Signal-to-positive （S/P） ratio for each sample was determined according to the following formula： （adjusted ODSample-adjusted ODNeg）/（adjusted ODPos-adjusted ODNeg）, where adjusted ODSample is the average OD for the swine serum sample, adjusted ODPos is the average OD for the positive control, and adjusted ODNeg is the average OD for the negative control. Samples were judged to be positive at S/P values above ,a threshhold value of 0. 4-0. 5. The developed ELISA could be useful for detecting the antibody against North American strain.