Recombinant fusion proteins targeting CD47 and CD24, preparation and use thereof

A recombinant fusion protein, comprising an anti-CD24 antibody or an antibody fragment thereof, and a CD47 binding peptide,

• wherein the anti-CD24 antibody or antibody fragment thereof comprises a heavy chain variable region, a heavy chain constant region, and a light chain variable region, wherein the heavy chain variable region comprises a heavy chain variable CDR-1 (HV-CDR1), a HV-CDR2 and a HV-CDR3 having amino acid sequences set forth in SEQ ID NOs:
• 7, 8 and 9, respectively, the light chain variable region comprises a light chain variable CDR-1 (LV-CDR1), a LV-CDR2 and a LV-CDR3 having amino acid sequences set forth in SEQ ID NOs:
• 10, 11 and 12, respectively, and the heavy chain constant region has Fc binding affinity and is linked to C-terminus of the heavy chain variable region,
• wherein the CD47 binding peptide comprises a signal-regulatory protein (SIRP) extracellular domain having an amino acid sequence having at least 95% sequence identity to SEQ ID NO:
• 1,
• wherein the CD47 binding peptide is linked to the anti-CD24 antibody or antibody fragment thereof.