检测OMP28抗体不能有效诊断羊布鲁氏菌病

Antibody against OMP28 is not a reliable diagnostic target for brucellosis infected in sheep and goats

【目的】探索布鲁氏菌外膜蛋白OMP28作为羊布鲁氏菌病特异性检测方法的可行性。【方法】体外表达和纯化OMP28蛋白,建立并优化以OMP28重组蛋白为包被抗原的布鲁氏菌病ELISA诊断方法。以3个不同种属的4株布鲁氏菌(羊种布鲁氏菌16M和M28,猪种布鲁氏菌S1330,牛种布鲁氏菌2308)分别感染山羊和绵羊至42周,期间每隔2周收集血清,分别用布鲁氏菌LPS包被的ELISA和OMP28 ELISA方法对不同阶段的分离血清进行检测,比较2种不同ELISA对4株布鲁氏菌感染的山羊和绵羊的检测敏感性。【结果】4株布鲁氏菌感染的山羊和绵羊均产生高水平针对LPS的抗体,但是仅有B.melitensis 16M和B.melitensis M28感染的绵羊与B.melitensis 16M和B.abortus 2308感染的山羊可产生针对OMP28的抗体。【结论】基于OMP28的间接ELISA具有细菌属特异性和宿主动物品种特异性,通过检测OMP28抗体不能有效诊断羊布鲁氏菌病。

[Objective] The aim of this study is to evaluate the feasibility of using purified recombinant OMP28 to diagnose Brucella-infected sheep and goats. [Methods] We expressed and purified recombinant Brucella OMP28 protein in Escherichia coli system as a diagnostic antigen in an I-ELISA. Four different Brucella species（B. melitensis 16 M, B. melitensis M28, B. abortus 2308, and B. suis S1330） were used to inoculate sheep and goat and sera samples were collected every two weeks, till 42 weeks post-inoculation. The antibodies against LPS and OMP28 were parallel compared by LPS-based and OMP28-based I-ELISA respectively. [Results] All Brucella-infected individuals could produce high levels of antibodies against LPS, but only B. melitensis 16M- and B. melitensis M28-infected sheep and B. melitensis 16M- and B. abortus 2308-infected goats could produce antibodies against OMP28 and the OMP28 specific antibody were undetectable in the rest groups. [Conclusion] OMP28-based I-ELISA showed specificity for both Brucella species and host kinds, which obviously limited its reliability as an antigen for diagnosing brucellosis in sheep and goats.