戊型肝炎病毒中和性单克隆抗体的鉴定

Identification of Neutralizing Mon oclonal Antibodies to Hepatitis E Virus

阻断实验发现,用戊型肝炎病毒(HEV)衣壳蛋白重组抗原制备的8株抗HEV单克隆抗体(mAb),分别识别3个构象表位和2个线性表位。用抗体捕获反转录PCR方法证实,其中识别2个构象表位的3个mAb可以直接捕获HEV颗粒,表明这2个表位位于HEV颗粒的外表面。识别这两个表位的mAb8C11和8H3均可中和HEV对恒河猴的致病性和感染性。mAb8C11缩短排毒时间的效应较明显,而mAb8H3延迟机体抗HEV抗体阳转时间的效应较明显。二者的中和效应具有较明显的协同作用。中和单抗8C11、8H3对戊肝不同感染时期的血清均有显著阻断作用,Fab片段的阻断作用与完整抗体类似,表明这两个mAb对应的中和表位是HEV体液免疫应答的优势表位。

Blocking assays showed th at eight anti-HEV monoclonal antib odies(mAbs) preparated from a reco mbinant capsid protein of HEV reco gnized three conformational epitope s and two linear epitopes respecti vely.Three mAbs recognizing two co nformational epitopes could captur e HEV particles directly,which sugg ested that these two epitopes expo sed on the outer surface of the v irus particle.Both the mAbs 8C11 a nd 8H3 which recongnized these two epitopes respectively showed neutr alizing activity against the patho genicity and infectivity of HEV to rhesus monkey.The effect of shorte ning feces shedding was more o bvious in mAb 8C11 neutralizing gr oup,but the delay of seroconversio n was more obvious in mAb 8H3 neut ralizing group.The neutralizing ef fects were enhanced when both mAbs were used.Significant sera blockin g effect could be seen in both acu te phase and convalescent phase sa mples by mAb 8C11 and 8H3,and the blocking effect of Fab fragments o f the mAbs were the same as the wh ole antibodies,which suggests that the correspponding epitopes of the se two mAbs are the immunodominant epitopes in humoral immunoresponse against HEV.