SIRPα-targeting antibody or antigen binding fragment thereof, and preparation and application thereof

An Sirpα-targeting antibody or an antigen-binding fragment thereof, comprising a light chain variable region and a heavy chain variable region, wherein the antibody or the antigen-binding fragment thereof binds to human Sirpα-V1 and human Sirpα-V2, but faintly binds to or does not bind to human Sirpβ and Sirpγ, and does not bind to human T cells, and has the function of blocking the binding of Sirpα to CD47;

• wherein faintly bind means that the EC50 in the binding experiment is 10 nM≤EC50<50 nM;
• does not bind means that the EC50 in the binding experiment is 50 nM≤EC50 or that the binding signal is undetectable;
• the antibody or the antigen-binding fragment thereof also binds to one or more of Cyno Sirpα L932, L933, L936 and L937, but does not bind to Cyno Sirpα L938 and L939;
• wherein the amino acid sequence of the L932 has a NCBI sequence number of NP_001271679.1 and as shown in SEQ ID NO:
• 62, the amino acid sequence of the L933 has a NCBI sequence number of NP_001271679.2 and as shown in SEQ ID NO:
• 63, the amino acid sequence of the L936 is as shown in SEQ ID NO:
• 3, the amino acid sequence of the L937 is as shown in SEQ ID NO:
• 4, the amino acid sequence of the L938 is as shown in SEQ ID NO:
• 5, and the amino acid sequence of the L939 is as shown in SEQ ID NO:
• 6;
• the light chain variable region comprises the following CDRs:
• VL CDR1 as shown in the amino acid sequence of SEQ ID NO:
• 11;
• VL CDR2 as shown in the amino acid sequence of SEQ ID NO:
• 12;
• and VL CDR3 as shown in the amino acid sequence of SEQ ID NO:
• 13;
• and the heavy chain variable region comprises the following CDRs:
• VH CDR1 as shown in the amino acid sequence of SEQ ID NO:
• 14;
• VH CDR2 as shown in the amino acid sequence of SEQ ID NO:
• 15;
• and VH CDR3 as shown in the amino acid sequence of SEQ ID NO:
• 16.