definiens: shall mean any molecule, free of a cell or drug conjugate, including full immunoglobulin molecules ( such as IgG, IgM, IgE, IgA, IgD and IgY molecules ), single domain immunoglobulin molecules ( such as VHH or isolated VL or VH domains ), and immunoglobulinfragments ( such as scFv, Fv, and Fab molecules ), or combinations thereof, that has an amino acid sequence by virtue of which it specificallyinteracts with an antigen, molecule, immunogen, or hapten, and wherein that amino acid sequence contains a functionally operating region ofan antibody variable region ( such as a heavy chain complementary determining region or a light chain complementarity determining region),and / or includes any naturally occurring, engineered, or recombinant form of any such molecule, any fragment or derivative thereof, andpolynucleotides encoding thereof