人Rh(D)血型抗原模拟表位的筛选和鉴定

摘要

Objective To screen the mimic epitopes of Rh(D)blood group antigens and identify their immunity from phage display peptide library.Methods A twelve mer phage peptide library was biopanned with anti-Rh(D)monoclonal antibody immobilized on plastic surface.After three round panning,thirty-five clones were randomly selected and positive clones were identified by ELISA and cross-reaction,followed by antibody competition inhibition assay and DNA sequencing to obtain the mimic epitopes of Rh (D)blood type antigens.The target phage clones were characterized and the antigenicity was analyzed by Western blot.Results After the third round screening,phages were enriched,and eleven positive clones were obtained.According to sequencing and competition inhibition analysis,the same"-WP-Q-"structure existed in seven of the eleven clones,and they had more than 40%inhibition ratio.The other clones had no same characteristics with low inhibition ratio possibly due to non-specific binding.Western blot analysis indicated that these phage clones could be specifically recognized by the anti-Rh(D)serum and they shared the same antigenicity of Rh(D)protein.Conclusions Rh(D)mimotope of"-WP-Q-"structure is successfully obtained by phage peptide library screening with anti-Rh(D)monoelonal antibody.The results lay the foundation for further exploration of pathogenesis and vaccine development of Rh(D)hemolytic diseases of newborn.%目的 从噬菌体随机肽库中筛选人Rh(D)血型抗原模拟表位,并对其免疫学活性进行鉴定.方法 以抗Rh(D)单克隆抗体作为固相筛选分子,对噬菌体随机十二肽库进行3轮"吸附-洗脱-扩增"筛选过程,随机挑选35个克隆,经噬菌体ELISA和交叉反应试验,确定阳性克隆,再对这些克隆进行DNA序列测定和抗体竞争抑制试验,以获取人Rh(D)血型抗原模拟表位.然后采用蛋白质免疫印迹法(Western blot)对所获噬菌体进行鉴定和抗原性分析.结果 经过3轮淘洗后,噬菌体得到富集,获得11个阳性克隆.DNA序列测定和竞争抑制实验结果表明,这11个克隆噬菌体所展示的外源多肽中有7个克隆氨基酸序列含有相同的色氨酸(W)、脯氨酸(P)和谷氨酰胺(Q)结构(-WP-Q-),且均具有40%以上的抑制率;其余4个克隆没有共性,抑制率较低,可能为非特异性结合.Western blot分析表明,被选定的噬菌体能被抗Rh(D)血清特异识别,具有类似于Rh(D)蛋白的抗原性.结论 利用抗Rh(D)单克隆抗体筛选噬菌体随机肽库,成功获得含有(-WP-Q-)结构的Rh(D)抗原模拟表位,为进一步探讨Rh(D)新生儿溶血病的发病机制和疫苗的研究奠定基础.