Besides target staining/detection and quantification, for example, via Western blotting, immunohistochemistry, and flow cytometry, antibodies can be used for a variety of functional assays such as:

• Blocking – where an antibody binds its target, thus directly interfering with its function, for example, by blocking its ability to bind a ligand.
• Neutralization – here, an antibody binds its target and abolishes its downstream effects, for example, its ability to influence cell proliferation.
• Activation or agonism – this may occur when an antibody binds a receptor in a manner that mimics the binding of the receptor’s natural ligand, resulting in antibody-mediated downstream signaling.
• Immunodepletion – removal of a target protein by sequestering it with an antibody.