Reporter protein fused antibodies

A method of detecting a target molecule in a sample comprising the step of contacting the target molecule with a first reporter protein fusion antibody;

• wherein the first reporter protein fusion antibody comprises an antigen-binding domain linked to a reporter protein or fragment thereof, wherein the antigen binding domain is specific for binding to an epitope on the target molecule, and wherein the reporter protein or fragment thereof is selected from the group consisting of a fluorescent protein, green fluorescence protein (GFP), a variant of GFP, a resonance energy transfer (RET) donor molecule, a RET acceptor molecule, a protein-fragment complementation assay (PCA) bait protein, a PCA prey protein, horseradish peroxidase (HRP), alkaline phosphatase (AP), luciferase, firefly luciferase, Renilla luciferase, deep sea shrimp luciferase, β-galactosidase, chloramphenicol acetyl transferase, glucose oxidase, acetate kinase, xanthine oxidase, and glucose 6-phosphate dehydrogenase.

A method of detecting at least two target molecules in close proximity in a sample comprising the steps of:

• a) contacting a first target molecule with a first reporter protein fusion antibody, wherein the first reporter protein fusion antibody comprises an antigen-binding domain linked to a reporter protein or fragment thereof, wherein the antigen binding domain is specific for binding to an epitope on the target molecule, and wherein the reporter protein of the first reporter protein fusion antibody is selected from the group consisting of a RET donor molecule, a RET acceptor molecule, a PCA bait protein, and a PCA prey protein,
• b) contacting a second target molecule with a second antibody linked to a reporter protein or fragment thereof selected from the group consisting of a RET donor molecule, a RET acceptor molecule, a PCA bait protein, and a PCA prey protein, wherein the second antibody comprises an antigen-binding domain specific for binding to an epitope on the second target molecule, and
• c) detecting a detectable signal generated when the first reporter protein fusion antibody is in close proximity to the second antibody.

A method of detecting or diagnosing a disease or disorder in a subject in need thereof, the method comprising the steps of administering to the subject at least one composition comprising a reporter protein fusion antibody, wherein the reporter protein fusion antibody comprises an antigen-binding domain linked to a reporter protein or fragment thereof;

• and detecting a detectable signal generated from the reporter protein of the reporter protein fusion antibody.