Mutant fully-humanized antibody specifically binding to CD22 and application of mutant fully-humanized antibody

The invention belongs to the technical field of immune engineering, and particularly relates to a fully human-derived mutant antibody specifically binding to CD22 or an antigen binding fragment thereof and application of the fully human-derived mutant antibody or the antigen binding fragment. The single-chain antibody provided by the invention is good in affinity performance, can be combined with CD22 positive cells in flow cytometry, can be specifically combined with CD22 antigens in molecular interaction research, is a natural fully humanized antibody, and has the advantages that the immunogenicity is greatly reduced compared with mouse antibodies, chimeric antibodies and humanized antibodies; the safety can be guaranteed to the maximum extent in clinical application, and the CD22 antibody is a fully humanized antibody with higher affinity and has potential clinical treatment advantages. 本发明属于免疫工程技术领域，具体涉及一种全人源的特异性结合CD22的突变抗体或其抗原结合片段及其应用。本发明提供的单链抗体亲和力性能良好，均可在流式细胞检测中与CD22阳性细胞结合，分子互作研究中显示可与CD22抗原特异性结合，而且为天然全人