A Novel Anti-CD24 Monoclonal Antibody: Unarmed, Conjugated and Bi-specific, for Targeting Human Malignancies

Abstract

Introduction: CD24 is a cell surface heavily glycosylated GPI-anchored protein. We have shown it to be an important oncogene in many tumors a poorer prognosis. It is highly expressed in HMs and in a large variety of solid tumors. The creation of chimeric humanized and bi-specific antibodies was a major breakthrough. Aim: To characterize and improve the efficacy of humanized mAb anti-CD24 Results and Methods:In vivo antibody targeting and accumulation within a CD24 positive tumor and its excess clearance was demonstrated using live imaging and assessment of CD24 levels in the tumors before and after treatment. High affinity antibodies were selected and created from combinatorial phage displayed antibody libraries with varying diversity at randomized positions. A chosen matured clone was isolated and showed higher binding strength and selective recognition and binding to the CD24 antigen. Its stability and pharmacokinetics parameters were enhanced. The matured antibody mediates ADCC in vivo, using a PDX model of CRC, the mAb was more effective than KEYTRUDA. Recombinant bispecific antibodies, targeting CD24 and CD30, were established and their specific binding was verified and compared to that of each monospecific antibody. Based on a glycan microarray, the binding of the different antibody derivatives was proved to be specific to the core protein and not to its sugar residues. Conclusion: CD24 is a promising target for many solid and hematological malignancies. The matured humanized anti-CD24 mAb is more effective than the parental Ab. The susceptibility of tumor cells to bispecific antibodies will be more effective and less toxic.