title: Single-stranded DNA aptamer targeting and neutralization of anti-D alloantibody: a potential therapeutic strategy for haemolytic diseases caused by Rhesus alloantibody.
abstract: Rhesus (Rh) D antigen is the most important antigen in the Rh blood group system because of its strong immunogenicity. When RhD-negative individuals are exposed to RhD-positive blood, they may produce anti-D alloantibody, potentially resulting in delayed haemolytic transfusion reactions and Rh haemolytic disease of the foetus and newborn, which are difficult to treat. Inhibition of the binding of anti-D antibody with RhD antigens on the surface of red blood cells may effectively prevent immune haemolytic diseases.
  
  
  
  In this study, single-stranded (ss) DNA aptamers, specifically binding to anti-D antibodies, were selected via systematic evolution of ligands by exponential enrichment (SELEX) technology. After 14 rounds of selection, the purified ssDNA was sequenced using a Personal Genome Machine system. Haemagglutination inhibition assays were performed to screen aptamers for biological activity in terms of blocking antigen-antibody reactions: the affinity and specificity of the aptamers were also determined.
  
  
  
  In addition to high specificity, the aptamers which were selected showed high affinity for anti-D antibodies with dissociation constant (Kd) values ranging from 51.46±14.90 to 543.30±92.59 nM. By the combined use of specific ssDNA aptamer 7 and auxiliary ssDNA aptamer 2, anti-D could be effectively neutralised at low concentrations of the aptamers.
  
  
  
  Our results demonstrate that ssDNA aptamers may be a novel, promising strategy for the treatment of delayed haemolytic transfusion reactions and Rh haemolytic disease of the foetus and newborn.
authors.affiliation: Shenzhen Blood Centre, Institute of Transfusion Medicine, Shenzhen, China.
authors.forename: Yinze
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Shenzhen Blood Centre, Institute of Transfusion Medicine, Shenzhen, China.
authors.forename: Fan
authors.initials: F
authors.lastname: Wu
authors.affiliation: Shaanxi Blood Centre, Xi'an, China.
authors.forename: Manni
authors.initials: M
authors.lastname: Wang
authors.affiliation: Shenzhen Blood Centre, Institute of Transfusion Medicine, Shenzhen, China.
authors.forename: Naibao
authors.initials: N
authors.lastname: Zhuang
authors.affiliation: Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Huayou
authors.initials: H
authors.lastname: Zhou
authors.affiliation: Shaanxi Blood Centre, Xi'an, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Xu
mesh_terms: D052157:Aptamers, Nucleotide / Q000138:chemical synthesis / Q000737:chemistry* / Q000627:therapeutic use; D004899:Erythroblastosis, Fetal / Q000097:blood / Q000188:drug therapy; D006801:Humans; D007518:Isoantibodies / Q000737:chemistry*; D018029:Rho(D) Immune Globulin / Q000097:blood / Q000737:chemistry*; D052156:SELEX Aptamer Technique
chemical_list: D052157:Aptamers, Nucleotide; D007518:Isoantibodies; C061961:RHO(D) antibody; D018029:Rho(D) Immune Globulin