Abstract: Provided is a bi-functional fusion protein as well as its preparation method and use. The bi-functional fusion protein is composed of a monoclonal anti-human CD20 antibody linked to a first extracellular domain of human SIRP?. It is shown in in vitro tests that the bi-functional fusion protein is capable of binding to human CD20 and CD47 simultaneously, thus killing CD20+ tumor cells via antibody-dependent cell-mediated cytotoxicity and complement-dependent cytotoxicity, and is also capable of blocking CD47-SIRP? interaction such that macrophages are activated to attack tumor cells. The bi-functional fusion protein has evident anti-tumor activities.

Abstract: The present invention provides a recombinant fusion protein containing an anti-PD-L1 antibody, with at least one paratope of the anti-PD-L1 antibody linked via a linker to an extracellular Ig-like domain of a signal-regulator protein (SIRP) at N-terminus of a heavy chain or a light chain, wherein the recombinant fusion protein can bind to CD47, PD-L1 and FcR simultaneously. The present invention also provides a polynucleotide encoding the recombinant fusion protein, an expression vector containing the polynucleotide, a method for producing the recombinant protein and a method for treating a disease caused by over expression of CD47 and/or PD-L1 using the recombinant protein.

Abstract: The present invention provides a recombinant fusion protein containing a first extracellular Ig-like domain of a signal-regulator protein alpha (SIRP?), linked to an Fc fragment of a human IgG1. The present invention also provides a polynucleotide encoding the recombinant fusion protein, an expression vector containing the polynucleotide, a method for producing the recombinant protein and a method for treating a disease caused by over expression of CD47.