Development of a new anti-CD123 monoclonal antibody to target the human CD123 antigen as an acute myeloid leukemia cancer stem cell biomarker.

Acute myeloid leukemia (AML) is a clonal hematologic malignancy arising from a small population of leukemic cells initiating the disease. CD123 is differentially expressed in AML blasts compared with normal hematopoietic stem and progenitor cells. The aim of this study was to develop specific monoclonal antibodies (mAbs) directed against AML. Three BALB/c mice were immunized with the human CD123 antigen, and the immune spleen cells were fused with the SP2/0 myeloma cell line. Hybridomas were screened by indirect enzyme-linked immunosorbent assay (ELISA), and the positive hybrids were cloned by limiting dilution. The mAb isotype was determined, ascitic fluids were produced, and antibodies were purified using Fast protein liquid chromatography (Sephacryl S-200). The specificity of the hybridomas was examined by ELISA, cell-based ELISA, and flow cytometry. After three rounds of cell cloning, four anti-CD123 secreting hybridomas were obtained with the IgM isotype. Among them, one stable hybrid, designated sC1, exhibited the higher ability to recognize the CD123 antigen, as compared with the other hybridomas. Our results showed that sC1 has the ability to bind specifically to the CD123 antigen (41.36%) on the cell surface. The anti-CD123 mAb produced in this study may be useful for the development of both diagnostic and therapeutic purposes for AML.