人免疫球蛋白重链可变区基因的特征分析

Characterization of the Heavy Chain Variable Region Gene of Human Immunoglobulins

目的:分析五类免疫球蛋白重链可变区基因的特征.方法:收集IMGT/LIGM-DB数据库中人类五类Ig重链可变区的基因序列,利用IMGT/HighV-QUEST分析其基因取用、V区AA变化、CDR3氨基酸长度和构成以及连接多样性.结果:IgM、IgG和IgE均较多地取用IGHJ4、IGHV1-69和IGHV5-51,且在IgM、IgG、IgA与IgE中可观察到几个相似的优势V-J配对.IgD具有较高的V区突变,主要体现在FR3区的高突变(AA变化值为7.2±2.4),而IgM的每个结构域的突变均明显低于其他类Ig.此外,IgD具有较高P插入发生率和插入核苷酸数明显多于其他四类Ig.结论:本研究从基因特征上描绘了人类五类Ig相互间的相似性与差异性,这些结果可为抗体工程领域提供重要参考数据.

Objective: To analyze the characteristics of five types of immunoglobulin heavy chain variable region genes.Method: The gene sequences of the heavy chain variable regions of human Ig were obtained from the IMGT/LIGM-DB database.An extensive analysis of these genes was implemented using IMGT/HighV-QUEST, including gene usage, amino acid (AA)changes in V region, length distribution and composition of CDR3 amino acid and junctional diversity.Results: IGHJ4, IGHV1-69 and IGHV5-51 were more frequently used in IgM, IgG and IgE.And several similar superior V-J pairings were observed in IgM, IgG, IgA and IgE.There was a higher mutation level of V region in IgD which mainly reflected in FR3 region (number of AA changes=7.2±2.4), while the mutations in each domain of IgM were significantly lower than those of other Igs.In addition, IgD has a higher incidence of P insertion and a higher number of nucleotides than other Igs.Conclusion: This study describes the similarities and differences among human five types of Ig from the genetic characteristics.These results can provide important reference data for the field of antibody engineering.