中文摘要：

在禽类和哺乳类中存在的三肽囊素（Bursin），对禽类和哺乳类淋巴细胞具有重要的免疫调节功能及生理学活性。牛骨髓和肝脏中含有三肽囊素（Bursin）序列的前囊素（pro Bursin）的分离使我们假设：在鸟类和哺乳类中存在的三肽囊素可能是由前囊素酶解而来的。为了验证这种假设我们通过提取鸡法氏囊三肽囊素阳性细胞的mRNA、构建cDNA酵母展示文库、对酵母展示文库用流式细胞仪进行三轮抗三肽囊素单克隆抗体以及FITC标记山羊抗小鼠IgM单克隆抗体的分选，最后对第3次分选得到的酵母克隆随机挑20个进行测序。这20个克隆中并没有编码三肽囊素的核酸序列，因此我们推测：在鸡法氏囊内三肽囊素不是由其前体囊素的裂解而来，而可能是由一种类似微生物体内低分子量的多肽通过非核糖体途径有多肽合成聚合酶的聚合作用合成的，这需要进一步的试验验证。

英文摘要：

Bursin,being of immunological and physiological importance, has been identified in avian and mammalian animals. It was speculated that bursin in the chicken bursa of Fabricius （BF） may be cleaved with enzyme from precursor of bursin, similar to probursin in the bovine bone marrow and liver in mammalian. To test this hypothesis：a yeast eDNA expression library was constructed with bursin positive cells enriched from Bursa of Fabricius, screened by flow cytometry with anti - bursin monoclonal antibody and FITC labeled goat anti - mouse IgM monoclonal antibody and randomly sequenced 20 clones at the third screening round. Among the 20 sequenced clones, no yeast clone contained the DNA fragment encoding the bursin. So, the authors hy- pothesized that bursin may be synthesized, instead of cleavage from the product of the putative precursor genes ; in the similar manner to a series of low molecular weight peptides in non - ribosomal ways in the micro organism.This hypothesis requires further investigative studies to validate.