构建轻链次级库提高人抗TNF—α抗体的亲和力

目的：使用构建轻链次级库的方法，对已经获得的人源抗TNF－α单抗（mAb)的Fab进行轻链置换，并筛选具有更高亲和力的人源抗TNF－αmAb的Fab。方法首先，采用RT－PCR扩增正常人全套抗 轻链基因，并与已经获得的人源抗TNF－αmAb的重链基因配对，构建人源抗TNF－α噬菌体抗体的轻链次级库。然后筛选与TNF－α具有更高亲和力的克隆。结果，经过3轮的生物淘筛（biopanning)，获得了较原来的人源抗TNF－αmAbFab具有更高亲和力的人源抗体Fab。结论轻链次级库筛选法，能有效地提高抗体的亲和力，为解决噬菌体抗体库法制备的人源抗体亲和力较低这一难题，提供了一种有效的方法。

Affinity mature of humananti-TNF-

Aim To obtain human anti-TNF-α antibody Fabs with higher affinitythrough replacing the light chain of the human anti-TNF-α antibody Fab fragment by constructing a light chain second library. Methods Firstly, amplify the repertoire of the human light chains genes from human peripheral blood lymphocytes using RT-PCR and assemble them randomly with the heavy chain gene of the anti-TNFα antibody so as to construct a second light chain library which comprises a single heavy chain gene of the antibody to TNFα and all of the human light chain genes. Then select the antibody clones with higher binding affinity. Results Some new phage displayed antibodies, which had higher affinity for TNFα , were obtained from the new library through three rounds of biopanning. Conclusion constructing light chain second library could effectively improve the affinity of the antibody, and could be a valid method to overcome the disadvantage of the lower affinity of the human antibody from phage display.