猴D型逆转录病毒p27基因的原核表达及流式免疫荧光微球检测技术的建立

目的构建猴D型逆转录病毒的p27蛋白,并建立流式免疫荧光微球检测技术用于猴D型逆转录病毒的检测。方法通过PCR扩增p27基因片段,与p GEX-4T-1表达载体进行连接,转化至BL21(DE3)进行表达。通过SDS-PAGE分析蛋白表达的形式及最佳诱导时间。采取GST树脂纯化目标蛋白,包被磁珠,建立流式免疫荧光微球检测技术,用于临床样本的检测。结果重组蛋白以可溶的上清液进行表达,诱导的最佳时间为4 h。包被磁珠后,成功建立流式免疫荧光微球检测技术,对阳性血清稀释81倍仍可检测为阳性,对猴类其他病原的阳性血清无交叉反应,特异性强,与ELISA法同时对24份临床样本进行检测,其中3份样品的流式免疫荧光微球检测结果为阳性,ELISA检测结果为2份阳性,1份阴性,两种方法的检测结果符合率为96%。结论成功表达猴D型逆转录病毒p27蛋白,并运用该蛋白建立了灵敏度高,特异性强,样本需求少的流式免疫荧光微球检测技术,为后续推广应用多重流式免疫荧光微球检测技术奠定了基础。

Prokaryotic expression of p27 gene of simian type-D retrovirus and establishment of flow microsphere immunofluorescence assay

Objective The p27 gene of the simian type-D retrovirus was prokaryotically expressed to establish the flow microsphere immunofluorescence assay for detection of simian type-D retrovirus in nonhuman primates. Methods The gene of p27 was amplified by PCR and linked to the pGEX-4T-1 expression vector digested with the restriction enzymes of EcoR I and Xho I, and the recombinant pGEX-4T-1-p27 plasmid was transfected into the BL21 (DE3) cells for expression of target protein. The form of expressed protein and the optimal time for induction were analyzed by SDS-PAGE. The target protein was purified with GST resin and coupled with magnetic beads to establish the flow microsphere immunofluorescence assay for detection of simian type-D retrovirus in clinical specimens. Results The recombinant protein was expressed in the soluble supernatant, and the optimal time for induction was 4 h. After coupling the protein with the magnetic beads, the flow microsphere immunofluorescence assay was successfully established. Using this method, 81-fold diluted serum could still be detected as positive, and no cross-reaction was found in the positive serum of other pathogens of nonhuman primates, indicating the strong specificity of this method.A total of 24 clinical specimens were tested by this flow microsphere immunofluorescence assay as well as ELISA. Among all the 24 specimens, 3 samples were positive detected by the flow microsphere immunofluorescence assay, of which 2 were positive and 1 was negative by ELISA. The coincidence rate of these two methods was 96%. Conclusions The prokaryotic expression of p27 protein of the simian type-D retrovirus is successful and the flow microsphere immunofluorescence assay with high sensitivity, strong specificity and tiny samples needed is established, which lays the foundation for further application of the multi-flow microsphere immunofluorescence technique.