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Ｗｅｓｔｅｒｎ印迹结果表明抗天花粉蛋白（ｔｒｉｃｈｏｓａｎｔｈｉｎ，ＴＣＳ）单抗Ｔ８Ｃ１２能与ＣＮＢｒ裂解的ＴＣＳ片段结合，氨基酸组成分析结果显示该表位位于Ｎ端７２肽内。为进一步确定该表位的位置，用固定化的Ｔ８Ｃ１２对克隆于噬菌体Ｍ１３外壳蛋白ｐＩＩ的随机六肽库进行了两轮亲和筛选后，随机测定了１５个阳性克隆的ＤＮＡ序列，发现插入的六肽序列有高度同源性，均含Ｓｅｒ／Ｔｈｒ－（Ｘ）－Ｘ－Ａｒｇ结构，Ｘ代表疏水氨基酸。这一结构与天花粉蛋白Ｎ端７２肽第３～５位（Ｓｅｒ－Ｐｈｅ－Ａｒｇ）相关。人工合成的ＴＣＳ（１～８）肽能与ＴＣＳ竞争结合Ｔ８Ｃ１２，验证了ＴＣＳ的Ｎ端第３～５位是单抗Ｔ８Ｃ１２针对的抗原表位核心。
Western blotting showed that T8C12, a trichosanthin (TCS) monoclonal antibody, bound to the CNBr cleaved TCS fragment. Amino acid composition analysis showed that the epitope was located in the N-terminal 72 peptide. In order to further confirm the epitope location, we randomly selected 15 positive clones from the random hexapeptide library cloned on the phage M13 coat protein pII using immobilized T8C12 and found that the inserted Hexapeptide sequences are highly homologous, both containing Ser / Thr- (X) -X-Arg structure, X represents a hydrophobic amino acid. This structure is related to Trp-N-terminal 72 peptides, positions 3 to 5 (Ser-Phe-Arg). Synthesized TCS (1 ~ 8) peptide competed with TCS for binding to T8C12, and verified that the N-terminus 3 to 5 of TCS was the epitope-directed core of monoclonal antibody T8C12.