This present invention is related to a recombinant single-strand tri-specific antibody made from antitumor antibody, FC interlinker, anti-human CD3 antibody, HSA interlinker and anti-human CD28 antibody in turn. Particularly, the invention relates to an anti-CEA, anti-CD3 and anti-CD28 recombinant single-strand tri-specific antibody: C A-TsAb, which was constructed with three tandem antibody fragments (anti-CEA scFv, anti-CD3 scFv and anti-CD28 single-domain antibody) linked by two interlinkers (FC interlinker and HSA interlinker), and could be appended by c myc tag or histidine tag ((His)6-tag) in the C termination. It also concerns a metlhod for construction, expression and purification of the antibody. It also offers the encoded DNA sequence of the antibody, expression vectors and host cells for the vectors.
AN GENE ENGINF; ERING RECOMBINANT ANTI-CEA, ANTI-CD3 AND ANTI-CD28 SINGLE-CHAIN TRI-SPECIFIC ANTIBODY