SYNTHETIC IMMUNOGLOBULIN DOMAINS WITH BINDING PROPERTIES ENGINEERED IN REGIONS OF THE MOLECULE DIFFERENT FROM THE COMPLEMENTARITY DETERMINING REGIONS
Immunoglobulins which each have one or more amino acid modifications in at least one structural loop region of such immunoglobulins, where the modified loop region specifically binds to an epitope of an antigen to which an unmodified immunoglobulin does not significantly bind, obtained from display libraries.
1 . A modified immunoglobulin comprising at least one structural loop region of a CH3 constant domain, the structural loop region having at least one amino acid modification with respect to a structural loop region of a CH3 constant domain of an unmodified immunoglobulin, thereby forming at least one modified loop region,
wherein the modified loop region specifically binds to an epitope of an antigen, and wherein the structural loop region of the unmodified immunoglobulin does not bind to the epitope, and
wherein the modified loop region is obtained from a display library comprising at least 100 displayed immunoglobulins, each of the at least 100 displayed immunoglobulins having a modified loop region comprising an amino acid modification which is different than the amino acid modifications of the modified loop regions of the remaining displayed immunoglobulins.
2 . The modified immunoglobulin of claim 1 , wherein the modified immunoglobulin is obtained from a library comprising immunoglobulins displayed on the surface of a host.
3 . The modified immunoglobulin of claim 2 , wherein the host is selected from the group consisting of mammalian cells, bacterial cells, insect cells, and yeast cells.
4 . The modified immunoglobulin of claim 1 , wherein the modified immunoglobulin is obtained from a library comprising immunoglobulins displayed on the surface of phages, phagemids or viruses.
5 . The modified immunoglobulin of claim 1 , wherein the modified immunoglobulin is obtained from a library comprising immunoglobulins displayed by an in vitro technology.
6 . The modified immunoglobulin of claim 5 , wherein the in vitro technology is selected from the group consisting of polysome display, mRNA display, and ribosome-inactivation display.
7 . The modified immunoglobulin of claim 1 , wherein the modified immunoglobulin is obtained from a library comprising at least 1,000 displayed immunoglobulins.
8 . The modified immunoglobulin of claim 1 , wherein the modified immunoglobulin is obtained from a library comprising at least 10,000 displayed immunoglobulins.
9 . The modified immunoglobulin of claim 1 , wherein the modified immunoglobulin is selected from the group consisting of a full length immunoglobulin, an Fc fragment, and a CH3 domain.
10 . The modified immunoglobulin of claim 1 , wherein the immunoglobulin is of human origin.
11 . The modified immunoglobulin of claim 1 , wherein the modified immunoglobulin is derived from IgG1.
12 . The modified immunoglobulin of claim 1 , wherein the amino acid modification is selected from the group consisting of a deletion, a substitution, an insertion, and a combination thereof.
13 . The modified immunoglobulin of claim 1 , wherein the modified structural loop region comprises at least 6 amino acid modifications.
14 . The modified immunoglobulin of claim 1 , wherein the modified immunoglobulin comprises at least two modified loop regions.
15 . The modified immunoglobulin of claim 1 , wherein the modified immunoglobulin is conjugated to a label or reporter molecule selected from the group consisting of organic molecules, enzyme labels, radioactive labels, colored labels, fluorescent labels, chromogenic labels, luminescent labels, haptens, digoxigenin, biotin, metal complexes, metals, colloidal gold and mixtures thereof.
16 . The modified immunoglobulin of claim 1 , wherein the modified loop region is within an amino acid sequence selected from the group consisting of amino acids 7 to 21, amino acids 25 to 39, amino acids 41 to 81, amino acids 83 to 85, amino acids 89 to 103, and amino acids 106 to 117, where the numbering of the amino acid position of the domains is according to the IMGT.