Abstract:ABSTRACT:Objective To obtain DNA oligonucleotide aptamers which can specifically bind to TB IgG antibodies. Methods Purify TB patient serum to attain IgG antibodies which were targets of the screening.An random DNA library was subjected to rounds of selection by SELEX method against IgG antibodies purified from TB patient serum. Available ampters were cloned and sequenced. Binding of the aptamers to the antibodies was examined by biotin-streptavidin-horseradish peroxidase system. DNAMAN package was employed to analyze the sequences and the second structures of the aptamers. Moreover, aptamers were tested in TB patients (n=13) and health controls (n=16) by ELISA. Results IgG antibodies with the concentration 1.3 mg per ml were abtained.After 10 rounds of selection, high-affinity aptamers to TB IgG antibodies were obtained. 4 aptamers from 12 random selected aptamers showed high absorbency to TB IgG antibodies (A > 1.0). Pocket and stem-loops was the basis of aptamers binding to the antibodies by the analysis of structures. ELISA results showed that there was significant difference (P<0.05) between the positive and the negative samples by the analysis of serological detection based on aptamers of which absorbency was above 1.0 except one. Conclusion A set of aptamers affinity to TB IgG antibodies were successfully selected from the initial random DNA library and had considerably specifical binding ability.