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由分泌抗人Ｃ１－ＩＮＨＭｃＡｂ的杂交瘤Ｆ７细胞株提取总ＲＮＡ，合成与ＶＨ基因ＦＲ１和ＦＲ４互补的通用引物，以ＲＮＡ反转录合成的第一链ｃＤＮＡ为模板，ＰＣＲ法克隆出Ｆ７ＶＨ基因的ＤＮＡ片段。将分离获得的目的ＤＮＡ片段亚克隆入ｐＵＣ１８／１９测序载体，从两头进行双脱氧核苷酸随机终止法的ＤＮＡ序列测定。结果显示：ＶＨ基因是由３３３个碱基组成，编码１１１个氨基酸残基。通过国际联机检索进行ＥＭＢＬ和Ｋａｂａｔ基因库扫描发现，Ｆ７ＶＨＤＮＡ仅与Ｉｇ同源，符合小鼠Ｉｇ的ＶＨ基因特征；同源性为６０％～８５％，应归属于Ｉｇ的ＶＨ基因。根据Ｋａｂａｔ分类方法，Ｆ７ＶＨ基因推导的氨基酸顺序属于小鼠Ｉｇ的ＶＨ基因的Ⅱ（Ａ）亚组，是由ＶＨ－Ｄ－ＪＨ３重排产生；其框架区的９和６７位点为脯氨酸（Ｐｒｏ）和赖氨酸（Ｌｙｓ）（非芳香族氨氨酸），符合Ⅱ（Ａ）亚组框架残基结构模式；其ＣＤＲ３区含有７个氨氨酸残基，表明Ｃ１－ＩＮＨ抗原表面结构并不复杂；ＦＲ２和ＦＲ３的２２和８９位点为半胱氨酸残基（Ｃｙｓ），与ＶＨ片段二硫键形成有关。成功获得Ｆ７ＶＨ基因为进一步构建和表达单链Ｆｖ（ｓｃＦｖ）抗体打下良好的基础。
Total RNA was extracted from F7 cell line secreting anti-human C1-INHMcAb to synthesize universal primers complementary to FR1 and FR4 of VH gene. The first-strand cDNA synthesized by RNA reverse transcription was used as a template to clone F7VH gene DNA fragment. The isolated target DNA fragment was subcloned into the pUC18 / 19 sequencing vector and subjected to DNA sequencing of the dideoxynucleotide random termination method from both ends. The results showed that the VH gene consisted of 333 bases and encoded 111 amino acid residues. According to the EMBL and Kabat genebank scan by international online search, F7VHDNA was only homologous with Ig, which was in line with the characteristics of mouse Ig VH gene. The homology was 60% ~ 85%, which should be attributed to Ig VH gene. According to the Kabat classification method, the deduced amino acid sequence of the F7VH gene belongs to the subgroup II (A) of the VH gene of mouse Ig and is produced by the rearrangement of VH-D-JH3; the 9 and 67 sites in the framework region are proline (Pro) and Lys (non-aromatic amino acids), which are in line with the structural pattern of the residues in frame II (A); the CDR3 region contains 7 amino acid residues, which indicates that the surface of C1-INH antigen Structure is not complicated; FR2 and FR3 positions 22 and 89 cysteine residues (Cys), and the VH fragment disulfide bond formation. Successfully obtaining the F7VH gene lays a good foundation for further construction and expression of single-chain Fv (scFv) antibodies.