模拟鼠伤寒脂多糖表位合成肽的初步研究  

Study on antigenicity of peptides mimotopes of S.Typhi lipopolysaccharide

作　　者：郑山根[1] 文维延[1] 刘北一[1] 朱平[1] 富宁[1] 

机构地区：[1]南方医科大学基础部免疫教研室,广州510515

出　　处：《免疫学杂志》2005年第3期166-169,共4页Immunological Journal

基　　金：国家自然科学基金资助项目(30070769)

摘　　要：目的探讨3种模拟LPS表位的合成肽的抗原性。方法固相合成模拟LPS表位的线性十二肽P12(GPPQW-FFSQPQL)、环七肽13a(SACPSWASFWCGG)和13b(SACFQFYPAACGG),与钥孔嘁血蓝蛋白或蓝载体交联,ELISA鉴定合成肽-载体交联物与抗LPS抗体的反应性,竞争ELISA鉴定游离的合成肽对抗LPS抗体与LPS、表达LPS模拟位的阳性噬菌体克隆结合的抑制。结果合成肽-载体交联物可与LPS抗体结合;游离环七肽13a可抑制抗LPS单克隆抗体与LPS结合(IC50=125μg/mL)及抗LPS单克隆抗体与阳性噬菌体克隆K1的结合(IC50=15.6μg/mL);游离十二肽P12抑制抗LPS单克隆抗体与LPS结合(IC50=550μg/mL)及阳性噬菌体克隆P12与抗LPS单克隆抗体结合(IC50=375μg/mL);游离环七肽13b可抑制噬菌体克隆P4和LPS多克隆抗体的结合(IC50=31.25μg/mL)。结论模拟LPS表位的合成肽可模拟LPS表位的抗原性,环肽优于线性肽。Objective To study the antigenicity of 3 peptides which mimic lipopolysaccharide (LPS) epitope. Methods Three peptide mimotopes of LPS, linear P12 (GPPQWFFSQPQL), cyclic 13a (SACPSWASFWCGG), and cyclic 13b (SACFQFYPAACGG), were synthesized and conjugated to carrier protein of keyhole limpet haemocyanin or blue carrier. The binding of peptide-carrier to anti-LPS antibody was identified by ELISA. The inhibitions of free synthetic peptides on binding between anti-LPS antibody and LPS, and on binding between anti-LPS antibody and phage clones mimicing epitopes of LPS were identified by competitive ELISA. Results Peptide-carrier could bind to anti-LPS antibody. Free peptide 13a could inhibit the binding of anti-LPS monoclonal antibody (mAb) to LPS (IC_ 50 = 125 μg/mL) and the binding of phage clone K1 to anti-LPS mAb (IC_ 50 = 15.6 μg/mL). Free peptide P12 could inhibit the binding of anti-LPS mAb to LPS (IC_ 50 = 550 μg/mL) and the binding of phage clone P1 to anti-LPS mAb (IC_ 50 = 375 μg/mL). Free peptide 13b could inhibit the binding of phage clone P4 to polyclonal anti-LPS antibody. Conclusion The results demonstrate that synthesized peptides mimotopes of LPS have the antigenicity of LPS epitopes, and that the antigenicity of cylcic peptide is better than that of linear peptide.

关 键 词：脂多糖 模拟肽 抗原性 

分 类 号：R392.1[医药卫生—免疫学]