Lucero N E, Foglia L, Ayala S M, Gall D, Nielsen K
Administración Nacional de Laboratorios e Institutos de Salud Dr. C. G. Malbrán, 1281 Buenos Aires, Argentina.
J Clin Microbiol. 1999 Oct;37(10):3245-8. doi: 10.1128/JCM.37.10.3245-3248.1999.
The methods commonly used for human brucellosis serological testing are agglutination tests and the complement fixation test (CFT). Among the newer serological tests, primary binding assays were developed to improve sensitivity and specificity. The competitive enzyme immunoassay (CELISA) for the detection of serum antibody to Brucella is a multispecies assay which appears to be capable of differentiating vaccinal and cross-reacting antibodies from antibodies elicited by field infection in cattle. The competing monoclonal antibody used in this assay is specific for a common epitope of smooth lipopolysaccharide (S-LPS). In this study, we compared the CELISA to the classical tests for the diagnosis of human brucellosis. The CELISA cutoff value was determined to calculate its diagnostic specificity and sensitivity. A survey was performed with 911 sera. Of the sera, 341 were from an asymptomatic population that tested negative with conventional serological tests (screening and confirmatory). Based on these samples, the CELISA specificities were determined to be 99.7 and 100% with cutoff values of 28 and 30% inhibition (%I), respectively. In a further study with 393 additional sera from an asymptomatic population found negative by the conventional screening tests, the CELISA specificities were calculated to be 96.5 and 98.8% with cutoff values of 28 and 30%I. The CELISA sensitivities were determined to be 98.3 and 94.8% with cutoff values of 28 and 30%I, respectively, for sera from 116 individuals found positive by the classical tests. For the 51 culture-positive patients, CELISA was positive for 100%, the CFT was positive for 92%, and the standard tube agglutination test (TAT) was positive for 100%. The CELISA specificity was 100% for 31 sera from patients found negative by conventional serological tests but with brucellosis-like symptoms. The CELISA is fairly rapid to perform, somewhat faster than TAT, and cross-reacts less with other antigens (or antibodies) than the conventional tests. Further, the CELISA is simpler to perform that the CFT and may readily be standardized by the use of purified S-LPS antigen and monoclonal antibody for competition.
用于人类布鲁氏菌病血清学检测的常用方法是凝集试验和补体结合试验（CFT）。在较新的血清学检测方法中，开发了直接结合试验以提高灵敏度和特异性。用于检测布鲁氏菌血清抗体的竞争酶免疫测定法（CELISA）是一种多物种测定法，似乎能够区分疫苗接种和交叉反应抗体与牛群野外感染引发的抗体。该测定法中使用的竞争单克隆抗体对光滑脂多糖（S-LPS）的共同表位具有特异性。在本研究中，我们将CELISA与诊断人类布鲁氏菌病的经典检测方法进行了比较。确定了CELISA的临界值以计算其诊断特异性和灵敏度。对911份血清进行了调查。其中，341份来自无症状人群，这些人群通过传统血清学检测（筛查和确证）呈阴性。基于这些样本，CELISA的特异性分别为99.7%和100%，临界值分别为28%和30%抑制率（%I）。在对另外393份来自无症状人群且经传统筛查试验呈阴性的血清进行的进一步研究中，CELISA的特异性计算结果分别为当临界值为28%I时为96.5%，当临界值为30%I时为98.8%。对于经经典检测呈阳性的116名个体的血清，当临界值为28%I和30%I时，CELISA的灵敏度分别确定为98.3%和94.8%。对于51名培养阳性患者，CELISA的阳性率为100%，CFT的阳性率为92%，标准试管凝集试验（TAT）的阳性率为100%。对于31份来自经传统血清学检测呈阴性但有布鲁氏菌病样症状患者的血清，CELISA的特异性为100%。CELISA操作相当快速，比TAT稍快，并且与其他抗原（或抗体）的交叉反应比传统检测少。此外，CELISA比CFT操作更简单，并且通过使用纯化的S-LPS抗原和竞争单克隆抗体可以很容易地实现标准化。
