Evolution And Functional Identification Of Aptamer Binding B Cell Activating Factor

To screen single-strand DNA aptamers specifically binding B cell activating factor belonging to the TNF family(BAFF) and identify its affinity. We applied the technology of systematic evolution of ligands by exponential enrichment(SELEX), separated ssDNA ligand by means of interaction between random oligonucleotide library and BAFF and then obtained ssDNA aptamers binding recombinant human BAFF through symmetric PCR and asymmetric PCR amplification. The bonding force was identified by dot blotting and the relevant affinity was compared by enzyme linked aptamer assay. Through optimally designed experiments before every round of SELEX, such 13 times later,six types of different sequences were obtained from sequencing of 42 clones.All six type sequences can bind BAFF in dot blotting test. Through comparing the optical density of six sequences in enzyme linked aptamer assay , the sequence 44 has highest optical density(p<0.05), which indicated relatively highest bonding force. The ssDNA aptamers binding BAFF was obtained initiatively, laying a base for developing new reagent for treating and diagnosis of autoimmune diseases and tumors.