Abstract: The invention relates to a chimeric antibody conjugate comprising an antigen binding region of a non-human antibody and an immunoglobulin constant region which comprises at least one CH domain or epitope thereof, with the proviso that the constant region is not a naturally occurring FC fragment. A bifunctional molecule for use in labelling an antibody derived from a first species, the bifunctional molecule comprising a binding region which binds to the antibody of the first species or to one or more groups provided thereon, and a constant region derived from an antibody of a second species, the constant region comprising at least one CH domain or an epitope thereof. The present invention relates to bifunctional molecules and complexes which are useful as positive control reagents in antibody based diagnostic tests. The present invention also relates to polynucleotides encoding these bifunctional molecules, and to diagnostic assays involving the use of these molecules.

Abstract: This invention provides polyvalent or polyspecific protein complexes, comprising three or more polypeptides which associate to form three or more functional target-binding regions (TBRs), and in which each individual polypeptide comprises two or more immunoglobulin-like domains which are covalently joined together, such that two Ig-like domains in a single polypeptide do not associate with each other to form a TBR. By using a linker peptide of fewer than three amino acid residues the immunoglobulin-like domains of the individual polypeptides are prevented from associating, so that complex formation between polypeptides is favoured. Preferably the polyvalent or polyspecific protein is a trimer or tetramer. The proteins of the invention have specificities which may be the same or different, and are suitable for use as therapeutic, diagnostic or imaging agents.

Abstract: This invention provides polyvalent or polyspecific protein complexes, comprising three or more polypeptides which associate to form three or more functional target-binding regions (TBRs), and in which each individual polypeptide comprises two or more immunoglobulin-like domains which are covalently joined together, such that two Ig-like domains in a single polypeptide do not associate with each other to form a TBR. By using a linker peptide of fewer than three amino acid residues the immunoglobulin-like domains of the individual polypeptides are prevented from associating, so that complex formation between polypeptides is favoured. Preferably the polyvalent or polyspecific protein is a trimer or tetramer. The proteins of the invention have specificities which may be the same or different, and are suitable for use as therapeutic, diagnostic or imaging agents.

Abstract: A target-binding polypeptide having (a) a stable core polypeptide region (SCR); and (b) at least one target-binding region (TBR), in which the target-binding region(s) are covalently attached to the SCR and which have optionally been subjected to a maturation step in order to modify the specificity, the affinity or the avidity of binding to the target. The polypeptides may self associate to form stable dimers, aggregates or arrays. The polypeptides of the invention have utility in the diagnostic, therapeutic, predictive or preventative fields of the pharmaceutical and health care industries, as well as more general application in the detection and assay of chemical entities.