FUSION PROTEIN COMPRISING SIRPa MUTANT

A fusion protein, comprising:

• a first binding domain that specifically binds to CLDN18.2;
• and
• a second binding domain that specifically binds to CD47 protein;
• wherein, the second binding domain has at least one of the following properties:
• (a) binding to CD47 protein with a KD value of 4×10−8 M or lower;
• (b) specifically blocking the interaction between CD47 protein and SIRPα;
• (c) not inducing coagulation;
• and
• (d) inhibiting the growth and/or proliferation of tumors or tumor cells;
• and wherein the second binding domain comprises a mutant of human SIRPα variant 1, and the mutant comprises an amino acid mutation at one or more positions compared with the 33rd-149th amino acid sequence of SEQ ID NO:
• 22.