A族链球菌(GAS)Fba蛋白单克隆抗体对应表位核心氨基酸的确定

目的:对A族链球菌Fba蛋白McAb2所对应的表位进行定位.方法:以初步定位的表位区段为线索合成三段重叠多肽,dot-ELISA检测McAb2与合成肽的亲合力,并以McAb2为靶分子,利用噬菌体随机七肽库进行亲和筛选,用竞争ELISA鉴定阳性克隆.结果:dot-ELISA检测结果表明Fba_(100-112)肽段与McAb2的结合能力最强.经过3轮亲和筛选后,随机挑选20个噬菌体克隆,竞争ELISA对其与McAb2的亲和力做检测,其中12个克隆显示较强的阳性结果.阳性克隆DNA测序,与Fba基因第100位氨基酸至110位氨基酸中ITPDL同源性较高.结论:通过dot-ELISA将A族链球菌Fba蛋白McAb2对应的表位定位于100～112位氨基酸,结果同噬菌体随机肽库筛选的核心氨基酸位置吻合.为进一步研制表位肽疫苗、研究Fba蛋白及其单克隆抗体的生物学功能奠定了基础.

Determination of predominance amino acids specific for McAb2 to Fba protein of GAS

Objective:To identify monoclonal antibody McAb2 recognizing epitope of Fba of GAS.Methods:The overlapped peptides were synthesized and their abilities to bind McAb2 were detected by dot-ELISA.The predominance amino acids specific for McAb2 were screened using phage 7 peptide library.Results:The result by dot-ELISA analysis demonstrated that the synthetized peptide,amino-acid residues 100-112~(th),could bind McAb2 with high affinity.The predominance amino acids specific for McAb2 were ITPDL,which was located in 100-110~(th)aa of Fba by panning with phage 7 peptide library.Conclusion:The domain and the predominance amino acids of Fba recognized by McAb2 is determined.The results would contribute to the research of the role of Fba on the pathogenic mechanism of GAS,the identification of function of McAb2,and the development of epitope-peptide vaccine.