Method for selection and production of tailor-made highly selective and multi-specific targeting entities containing at least two different binding entities and uses thereof
Herein is reported a method for producing a bispecific antibody comprising the step of incubating (i) an antibody Fab fragment or a scFv antibody comprising within the 20 C-terminal amino acid residues the amino acid sequence LPX1TG (SEQ ID NO: 01), (ii) a one-armed antibody comprising a full length antibody heavy chain, a full length antibody light chain, and an Fc-heavy chain, whereby the full length antibody heavy chain and the full length antibody light chain are cognate antibody chains that thereof forms an antigen binding site, whereby the full length antibody heavy chain and the Fc-heavy chain are covalently linked to each other via one or more disulfide bonds forming an antibody hinge region, and whereby the Fc-heavy chain has an oligoglycine amino acid sequence at its N-terminus, and (iii) a Sortase A enzyme.
1. A purified one-armed antibody fragment comprising a full length antibody heavy chain, a full length antibody light chain, and an antibody heavy chain Fc-region polypeptide,
wherein the full length antibody heavy chain and the full length antibody light chain are cognate antibody chains complementary to each other and comprise a pair of variable domains (VH and VL) that form an antigen binding site,
wherein the full length antibody heavy chain and the antibody heavy chain Fc-region polypeptide are covalently linked to each other via one or more disulfide bonds forming an antibody hinge region, wherein the antibody heavy chain Fc-region polypeptide has the amino acid sequence GGCPX4C, wherein X4 is either S or P (SEQ ID NO: 08) at its N-terminus;
and wherein the amino acid sequence GGCPX4C, wherein X4 is either S or P (SEQ ID NO: 08) at the N-terminus of the antibody heavy chain Fc-region polypeptide of the one-armed antibody fragment is a substrate for sortase conjugation to a Fab fragment or a scFv antibody comprising within its 20 C-terminal amino acid residues the amino acid sequence LPX1TG, wherein X1 is any amino acid residue (SEQ ID NO: 01).
2. The purified one-armed antibody fragment of claim 1 , wherein the Fc-region comprises a mutation of the naturally occurring amino acid residue at position 329 and at least one further mutation of at least one amino acid residue selected from the group consisting of amino acid residues at position 228, 233, 234, 235, 236, 237, 297, 318, 320, 322 and 331 to a different residue, wherein the residues in the Fc-region are numbered according to the EU index of Kabat.
3. The purified one-armed antibody fragment of claim 1 , wherein the antibody heavy chain Fc-region polypeptide has the amino acid sequence GGCPPC (SEQ ID NO: 71) at its N-terminus.
4. The purified one-armed antibody fragment of claim 1 , wherein the antibody Fc-region is of the human IgG1 subclass.