推測T細(xì)胞庫（T cell repertoire)中多樣性在1010以上，其多樣性的原因與Ig相似，主要有以下幾方面。
1.胚系中有眾多的V、D和J基因片段 盡管TCRα和β基因中V基因片段數(shù)比Ig基因少，但J基因片段明顯比Ig基因?yàn)槎啵缧∈笾屑s50～100個(gè)Jα和至少12個(gè)Jβ基因片段，而IgH和κ鏈基因座中J基因片段各只有4個(gè)。
2.連接處連接的多樣性 與IgVDJ連接的多樣性相似。
3.N區(qū)的插入 N區(qū)插入在Ig基因重排中只發(fā)生在重鏈基因，而TCRα和β鏈基因均可發(fā)生N區(qū)的插入。此外，在TCRα和β鏈基因中都發(fā)現(xiàn)一種稱之為“易變性”（flexibility)的現(xiàn)象，如有一個(gè)以上Vα基因3′端可以連接到Jα片段。
4.TCRα與β鏈的隨機(jī)配對 人TCRαβ庫多樣性可推算為：α鏈（Vα（100)×Jα（100))×β鏈（Vβ（100)×Dβ（2)×Jβ（14))=2.8×107，這種多樣性尚未包括N區(qū)插入所擴(kuò)展的多樣性。
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