Patent ID: 8067167

Claim:
A method for producing a hybrid antibody or hybrid antibody fragment comprising: providing an initial antibody having specificity for a target; determining the amino acid sequence of a variable region of the initial antibody; and (i) selecting a first component of the variable region selected from the group consisting of FR1, FR2 and FR3; comparing the amino acid sequence of the first component of the variable region to amino acid sequences contained in a reference database of antibody sequences or antibody fragment sequences from a target species; selecting a first framework sequence from the database which demonstrates a high degree of homology to the first component; determining which germline gene family the first framework sequence was derived from; (ii) selecting a second component of the variable region which is different than the first component, the second component selected from the group consisting of FR1, FR2 and FR3; comparing the amino acid sequence of the second component to amino acid sequences contained in a reference database of antibody sequences or antibody fragment sequences from the target species; selecting a second framework sequence from the database which demonstrates a high degree of homology to the second component and which corresponds to the same germline gene family as the first sequence selected from the database in step (i); wherein the first and second framework sequences selected from the reference database are from different antibodies; and (iii) operatively linking nucleic acids encoding the selected framework sequences to nucleic acids encoding CDRs and unselected frameworks of the initial antibody, and expressing the linked nucleic acids to produce a hybrid antibody or hybrid antibody fragment.