De Massis F, Giovannini A, Di Emidio B, Ronchi G F, Tittarelli M, Di Giannatale E, Di Ventura M, Nannini D, Caporale V
Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise 'G. Caporale' (IZS A&M), Campo Boario, 64100 Teramo, Italy.
Vet Ital. 2005 Oct-Dec;41(4):291-9.
In the European Union, RB51 vaccine can be used only under strictly controlled conditions for the immunisation of cattle at risk of infection with Brucella abortus. A test is therefore necessary to distinguish vaccinated from unvaccinated animals. The complement fixation test with RB51 antigen (RB51-CFT), dot-blot and gamma-interferon used to identify vaccinated animals have been described, but sensitivity of the tests has been poor and positivity transient after calfhood vaccination. To avail of a rapid and accurate diagnostic tool, the authors produced, controlled and evaluated an experimental brucellin prepared from strain RB51 (RB51 brucellin). The potency of this brucellin was evaluated in guinea-pigs sensitised with RB51 and compared with a commercially available brucellin. Both allergens produced similar biological activity in guinea-pigs. The RB51 brucellin skin test was performed in 10 cattle 414 days after calfhood vaccination with RB51 when they were negative to the RB51-CFT. The skin test revealed 60% sensitivity (with a confidence interval of 95%, CI 30.8%-83.3%) and 100% specificity (CI 60.7%-100%). These findings limit the use of the skin test only for screening to detect RB51 vaccinated herds, not individual animals. Nevertheless, following intradermal inoculation of RB51 brucellin, a transient antibody increase to the RB51-CFT was observed, from day 9 to day 20 post inoculation with RB51 brucellin. This transient antibody increase, when evaluated in parallel with the RB51 brucellin skin test results, enables detection of individual vaccinated animals (sensitivity 100%; CI 76.2%-100%).
在欧盟，RB51疫苗仅可在严格控制的条件下用于对有感染牛流产布鲁氏菌风险的牛进行免疫接种。因此，有必要进行一项检测，以区分已接种疫苗和未接种疫苗的动物。已描述了用于识别已接种疫苗动物的用RB51抗原进行的补体结合试验（RB51 - CFT）、斑点印迹法和γ - 干扰素检测，但这些检测的敏感性较差，且在犊牛期接种疫苗后阳性反应短暂。为了获得一种快速准确的诊断工具，作者制备、控制并评估了一种由RB51菌株制备的实验性布鲁氏菌素（RB51布鲁氏菌素）。在对用RB51致敏的豚鼠中评估了这种布鲁氏菌素的效力，并与一种市售布鲁氏菌素进行了比较。两种变应原在豚鼠中产生了相似的生物学活性。在用RB51对10头牛进行犊牛期接种414天后，当它们对RB51 - CFT呈阴性时，进行了RB51布鲁氏菌素皮肤试验。皮肤试验显示敏感性为60%（95%置信区间，CI 30.8% - 83.3%），特异性为100%（CI 60.7% - 100%）。这些结果限制了皮肤试验仅用于筛查以检测接种了RB51疫苗的牛群，而非个体动物。然而，在皮内接种RB51布鲁氏菌素后，从接种RB51布鲁氏菌素后的第9天到第20天，观察到对RB51 - CFT的抗体出现短暂增加。当与RB51布鲁氏菌素皮肤试验结果平行评估时，这种短暂的抗体增加能够检测出个体接种疫苗的动物（敏感性100%；CI 76.2% - 100%）。
