Immunity: compare question

A research team develops a monoclonal antibody (MAb) that binds specifically to a surface protein of a novel influenza virus. They plan to use this MAb in two ways:

• As a diagnostic reagent to detect the virus in patient swab samples.
• As a therapeutic drug to treat patients with severe influenza.

Compare the principles underlying these two uses of the MAb. In your answer, refer to:

• the role of antibody structure in each use
• the type of immunity (if any) provided to the patient by each use.