A method of producing a non-immunogenic immunoglobulin for administration to a target species is provided wherein the method comprises substituting amino acid residues in framework regions of a donor immunoglobulin with amino acid residues present at a corresponding position in framework regions of at least one immunoglobulin derived from the target species. Also provided are antibodies produced by the method of the invention, including novel humanised and caninised anti-NGF antibodies. The invention extends to nucleic acids encoding same and to methods of treating pain and arthritis in a human or dog using said antibodies and/or nucleic acids.
