There is provided an antibody or antibody fragment that specifically binds to a multimeric or heterodimeric cytokine receptor, wherein the multimeric or heterodimeric cytokine receptor comprises:
a first polypeptide consisting of amino acid residues 20-732 of SEQ ID NO:111; and
a second polypeptide consisting of amino acid residues 28-429, amino acid residues 28-739 or amino acid residues 28-979 of SEQ ID NO:7.
