Multiple antigen binding molecular fusion, pharmaceutical composition, method for identifying linear epitope, and method for preparing multiple antigen binding molecular fusion

A multiple antigen-binding molecule fusion molecule comprising:

• a multiple antigen-binding molecule (α) which comprises
• an immune cell antigen-binding region which recognizes an antigen that comprises a polypeptide consisting of the amino acid sequence QDGNE (SEQ ID NO:
• 15) and wherein the immune cell antigen-binding region recognizes at least one type of immune cell antigen other than the antigen that comprises a polypeptide consisting of the amino acid sequence QDGNE (SEQ ID NO:
• 15), and a cancer antigen-binding region which recognizes a cancer antigen;
• a cancer tissue-specific protease-cleavable linker (β) which comprises a polypeptide consisting of a target sequence of a cancer tissue-specific protease;
• and
• a masking molecule (γ) which comprises a polypeptide consisting of the amino acid sequence QDGNE (SEQ ID NO:
• 15);
• wherein the multiple antigen-binding molecule (α) is an antibody or an antibody fragment comprising at least two Fv regions, and the cancer antigen-binding region and the immune cell antigen-binding region are formed by different Fv regions;
• wherein the cancer tissue-specific protease-cleavable linker (β) is fused to a heavy chain N-terminus or a light chain N-terminus of the Fv region that forms the immune cell antigen-binding region;
• wherein the multiple antigen-binding molecule (α) and the masking molecule (γ) are linked via the cancer tissue-specific protease-cleavable linker (β);
• and
• wherein the cancer tissue-specific protease-cleavable linker (β) and the masking molecule (γ) form a linear fusion polypeptide, and
• wherein the number of amino acids in the fusion polypeptide is 11 or more to 65 or less when the cancer tissue-specific protease-cleavable linker (β) is fused to the heavy chain N-terminus of the Fv region that forms the immune cell antigen-binding region;
• and
• the number of amino acids in the fusion polypeptide is 16 or more to 65 or less when the cancer tissue-specific protease-cleavable linker (β) is fused to the light chain N terminus of the Fv region that forms the immune cell antigen-binding region.