Patent ID: 8296079

Claim:
A method for producing a humanized antibody comprising VH and VL variable regions of an animal antibody of known sequence, comprising the steps of: a) experimentally obtaining a crystallographic structure of the VH and VL regions of the animal antibody; b) pre-selecting a series of 0 to n possible framework acceptors of human origin or of humanized antibodies, whose structures were determined experimentally with a resolution of no greater than 2.5 Å, wherein selected framework acceptors have a high level of homology and identity with the primary sequence of the framework of the animal antibody; c) conducting a structural comparison between the VH and VL variable regions of the animal antibody and the VH and VL regions of the framework acceptors of human origin or of humanized antibodies, respectively, by comparing on a three-variable graph: i) the value of the root mean square deviation (RMS, Å), wherein the RMS is calculated between atoms of alpha carbon constituting the respective amino acid skeletons, not considering atom pairs with an RMS exceeding 2 Å, ii) the percentages of alpha carbon atoms on which RMS was calculated, and iii) the percentage identity and/or homology of the overall primary structure and/or of the primary structure of the framework, in order to identify the VH region and the VL region of human origin or of humanized antibody with the smallest distance from the ideal coordinates, RMS=0 Å, 100% alpha carbon atoms and 100% sequence identity/homology; d) grafting in appropriate positions the sequences of the CDR regions of the animal antibody into the VH region and the VL region of human origin or of the humanized antibody identified in c); wherein the modifications of the antibody take place with recombinant DNA techniques.