The invention discloses bispecific recombinant
protein. The bispecific recombinant
protein comprises a high-affinity tumor-targeted arm and a low-affinity
fusion protein for blocking interaction of CD47 and SIRPalpha, wherein an
antibody corresponding to the high-affinity tumor-targeted arm is not combined with the CD47, and the bonding affinity to target antigens on
tumor cells is at least 6 times of the bonding affinity of the monomeric
fusion protein and
dimer corresponding to the low-affinity
fusion protein for blocking the interaction of the CD47 and the SIRPalpha to the CD47 on the tumorcells; the low-affinity fusion
protein for blocking mutual action of the CD47 and SIRPalpha contains SIRPalpha
extracellular truncation. The invention also discloses a nucleic-
acid molecule for encoding the recombinant protein and application of the recombinant protein and the nucleic-
acid molecule in preparation of medicines for treating tumors. The bispecific recombinant protein disclosed by the invention has the beneficial effects that the bonding abundance of
tumor targeting saturation of the recombinant protein with the function of adjusting macrophage is obviously improved by the bispecific recombinant protein, the
side effect of the non-
tumor targeting is reduced and the application value is large clinically.