Epitope regions of a thyrotrophin (TSH) receptor, uses thereof and antibodies thereto

A kit for screening for autoantibodies to a TSH receptor in a sample of body fluid obtained from a subject suspected of suffering from, susceptible to, having or recovering from autoimmune disease associated with an immune reaction to a TSH receptor, said kit comprising:

• (a) a soluble or solubilized TSH receptor comprising the amino acid sequence of amino acid residues 47 to 61 of SEQ ID NO:17 or SEQ ID NO:22;
• and
• (b) one or more binding partners, wherein the binding partner comprising an isolated monoclonal antibody or antigen binding fragment thereof that:
• binds to an epitope on the TSH receptor wherein the TSH receptor is from a species selected from a group consisting of porcine, bovine, feline, canine, mouse, rat and ovine;
• has a binding affinity for the TSH receptor of at least about 108 molar−1;
• is positive for thyroid stimulating activity at a concentration of 20 μg/ml in a cyclic AMP thyroid cell assay and wherein the binding partner is classified as positive if the thyroid stimulating activity of the binding partner is greater than 180 percent in the cyclic AMP thyroid cell assay, said percent thyroid stimulating activity comprising 100×(ratio of cyclic AMP produced in the thyroid cell assay in the presence of said binding partner to cyclic AMP produced in the thyroid cell assay in the presence of sera pooled from healthy blood donors);
• and
• inhibits TSH binding, the binding partner inhibiting binding of TSH to the TSH receptor in a coated tube binding assay by 61% to 83.3% at a concentration of 2 μg/ml to 20 μg/ml wherein the TSH receptor is immobilized on a surface of the tube and wherein the monoclonal antibody comprises the VH domain as shown in SEQ ID NO:67 paired with the VL domain as shown in SEQ ID NO:68;
• or the VH domain as shown in SEQ ID NO:69 paired with the VL domain as shown in SEQ ID NO:70;
• or the VH domain as shown in SEQ ID NO:71 paired with the VL domain as shown in SEQ ID NO:72.

A binding partner for a TSH receptor, the binding partner comprising an isolated monoclonal antibody or antigen binding fragment thereof that:

• has a binding affinity for the TSH receptor of at least about 108 molar−1;
• inhibits TSH binding, the binding partner inhibiting binding of TSH to the TSH receptor in a coated tube binding assay by 61% to 83.3% at a concentration of 2 μg/ml to 20 μg/ml wherein the TSH receptor is immobilized on a surface of the tube;
• and
• has heavy chain variable region CDRs contained within a heavy chain variable domain having an amino acid sequence selected from the group consisting SEQ ID NOs:
• 67, 69, and 71.

A binding partner for a TSH receptor, the binding partner comprising an isolated monoclonal antibody or antigen binding fragment thereof that:

• binds to an epitope on the TSH receptor;
• has a binding affinity for the TSH receptor of at least about 108 molar−1;
• is positive for thyroid stimulating activity at a concentration of 20 μg/ml in a cyclic AMP thyroid cell assay, wherein the binding partner is classified as positive if the thyroid stimulating activity of the binding partner is greater than 180 percent in the cyclic AMP thyroid cell assay, said percent thyroid stimulating activity comprising 100×(ratio of cyclic AMP produced in the thyroid cell assay in the presence of said binding partner to cyclic AMP produced in the thyroid cell assay in the presence of sera pooled from healthy blood donors);
• and
• inhibits TSH binding, the binding partner inhibiting binding of TSH to the TSH receptor in a coated tube binding assay by 61% to 83.3% at a concentration of 2 μg/ml to 20 μg/ml wherein the TSH receptor is immobilized on a surface of the tube and wherein the monoclonal antibody comprises a VH domain comprising amino acid residues 9 to 120 of SEQ ID NO:67 and a VL domain comprising amino acid residues 9 to 107 of SEQ ID NO:68;
• a VH domain comprising amino acid residues 9 to 120 of SEQ ID NO:69 and a VL domain comprising amino acid residues 9 to 107 of SEQ ID NO:70 or a VH domain comprising amino acid residues 9 to 120 of SEQ ID NO:71 and a VL domain comprising amino acid residues 9 to 107 of SEQ ID NO:72.

A binding partner for a TSH receptor, the binding partner comprising a monoclonal antibody or fragment thereof comprising a Fab domain for a TSH receptor, wherein the antibody is capable of binding to a TSH receptor so as to stimulate the TSH receptor, which comprises:

• an antibody heavy chain (HC) selected from the group consisting of:
• a HC comprising (SEQ ID NO:67), (SEQ ID NO:69) or (SEQ ID NO:71);
• and/or
• an antibody light chain (LC) selected from the group consisting of:
• a LC comprising (SEQ ID NO:68), (SEQ ID NO:70) or (SEQ ID NO:72).