两种方法筛选噬菌体肽库所获日本血吸虫抗原模拟表位的抗原性比较

目的比较两种不同方法筛选噬菌体肽库所获得的日本血吸虫抗原模拟表位的抗原性.方法以日本血吸虫病患者血清免疫球蛋白(Sj-Ig)作为靶分子, 分别以噬菌体12肽库(SjA)和经过蚯蚓免疫兔血清免疫球蛋白(L-Ig)筛选一轮后的噬菌体12肽库(SjB)为原肽库,进行3轮吸附-洗脱-扩增免疫筛选.随机挑取SjA和SjB蓝色噬菌斑各24个, 扩增后用ELISA方法检测其抗原性.结果 24个SjA克隆中有6个可以与Sj-Ig特异结合, 其中A491 nm值较高的2个克隆具有较好的特异性和敏感性;24个SjB克隆中有10个可以与Sj-Ig特异结合, 其中A491 nm值较高的5个克隆具有较好的抗原性.比较SjA 和SjB两组间克隆的抗原性,结果显示SjB的目的克隆具有更好的特异性和敏感性.结论从SjA 和SjB中均筛选到了对日本血吸虫病具有较高潜在诊断价值的抗原模拟表位,提示以异源性抗体结合后的肽库作为原肽库来筛选寄生虫抗原模拟表位是可行的,同时也为从噬菌体肽库中筛选抗原模拟表位提供了一个新的实验方法.

COMPARING ANTIGENICITY OF TWO KINDS OF ANTIGEN-MIMIC EPITOPES OF SCHISTOSOMA JAPONICUM SCREENED FROM PHAGE 12-MER LIBRARY USED DIFFERENT METHODS

Objective To compare the antigenicity of the mimic epitopes of diagnostic antigen of schistosomiasis from phage 12-mer peptide library and phage 12-mer peptide library screened by anti-lumbricus immunoglobulin (L-Ig ). Methods SjA was the original phage 12-mer peptide library and SjB was the phage peptide library immunoscreened by specific L-Ig, which was purified from sera of rabbits. Specific Sj-Ig,purified from sera of patients with schistosomiasis, was used to immunoscreen SjA and SjB, respectively. After three rounds of panning, 24 positive plaques were selected and amplified from SjA and SjB, respectively. ELISA was used to examine the antigenicity of each clone. The sensitivity and the specificity of positive phage clones were confirmed by detecting the sera of different parasitic patients. Results Six phage clones of SjA could bind to the sera of schistosomiasis patients, while ten clones of SjB had a same sensitivity in ELISA. Two of six SjA positive clones showed high immuno-activity while five of six SjB positive clones did. ELISA results showed positive clones of SjB had higher specificity and sensitivity. Conclusion The mimic epitopes obtained both from SjA and SjB played a good role in serodiagnosis of schistosomiasis, which built a good foundation for the further study for obtaining a new diagnostic reagent.