磁性颗粒标记单抗对肠道病毒EV71感染的体外MRI检测

Detection of Enterovirus EV71 Infection by Magnetic Particle Labeled Monoclonal Antibody in Vitro by MRI

目的探讨MRI通过磁性颗粒标记抗体可视化EV71病毒感染细胞分布的可行性。方法提取临床EV71分离株制备单克隆抗体,Fe磁性颗粒标记纯化的单克隆抗体11R12-IgG,磁化标记的单抗11R12-IgG运用与protein-A/G-beads共孵育及SDS-PAGE分析测量抗体吸附效率。然后用ELISA测试11R12-IgG-beads与纯化的VP1抗原的结合能力。最后MRI信号分析磁性颗粒标记的抗体在细胞水平上检测病毒感染分布的能力。结果抗体在磁珠的首次吸附效率约为75.5%,经过第二次洗涤后只有少量抗体洗脱;并SDS-PAGE分析显示首次吸附在磁珠上的抗体浓度仅略低于原始浓度,都证实抗体以较高的效率成功吸附到磁珠上。ELISA结果表明磁珠结合抗体后,抗体识别抗原的能力不受影响。MRI结果显示磁颗粒11R12-IgG组能检测到显著的MRI信号,而仅磁珠组或者仅IgG组则不能检测到相应的MRI信号。结论磁颗粒-IgG能在细胞水平特异,在体外水平有效地检测EV71病毒的感染,为确定病理损伤和病毒的共定位奠定了重要基础。

Objective To explore the feasibility of MRI in visualizing distribution of virus infected cells through magnetic-particle labeled antibody.Methods Extract clinical EV71 isolated strain to prepare monoclonal antibody.Take Fe magnetic particle to label purified monoclonal antibody 11 R12-IgG for which protein-A/G-beads co-incubation and SDS-PAGE were used to analyze and measure absorption efficiency of antibody.ELISA was then used to examine binding capacity of 11 R12-IgG-beads and purified VP1 antigen.Finally,MRI signal was used to analyze capacity of magnetic-particle labeled antibody to examine distribution of infected cells at cellular level.Results Initial absorption efficiency of antibody on magnetic beads was about 75.5%.After second washing,only a few antibodies were eluted.Meanwhile,SDS-PAGE analysis showed that the concentration of antibody initially absorbed on the magnetic beads was slightly lower than the original concentration,all verifying that antibody was successfully absorbed on the magnetic beads with higher efficiency.ELISA results indicated that after the magnetic beads were bound to the antibody,capacity of antibody to identify antigen was not affected.MRI results demonstrated that obvious MRI signal could be detected in the magnetic particle 11 R12-Ig G group while relevant MRI signal could not be detected in magnetic beads group or Ig G group.Conclusion Magnetic particle-Ig G can be specific at the cell level and effectively detect EV71 virus infection in vitro,laying an important foundation for determining pathological damage and virus co-localization.