ABSTRACT
Objective: To screen out DNA binding proteins specifically recognizing CpG immunostimulatory sequence (ISS) for further investigating the molecular mechanisms of ISS. Methods: Yeast one hybrid system was adapted in screening a human bone marrow cDNA library using 4 copies of ISS as bait. The ISS binding activity of the positive clone was confirmed by electrophoretic mobility shift assay (EMSA). Results: Four dual positive colonies were obtained, two of them encoded proteins with unknown functions. The other 2 encoded light chains of immunoglobulin with amino sequences homology to anti DNA Ab and HBsAb respectively. EMSA showed HBsAb specifically bound to CpG ODN at pH6.4 and pH 5.8. Conclusion: HBsAb may have ISS specific DNA binding activity.