Patent ID: 7351540

Claim:
A method of identifying a recombinant antibody or antibody domain which binds to an antigen of interest, comprising: (i) providing an antibody library, wherein each antibody member comprises within its amino acid sequence or terminal to it, one or more individual identifier sequence amino acid tracts which is unique to said antibody and wherein said sequence is further flanked by one or more protease sensitive sites: (ii) contacting said antibody of the library with one or more of said antigens to form an antigen-antibody complex, (iii) isolating the antigen-antibody complex of (ii), (iv) digesting said antigen-antibody complex to cleave the protease sensitive sites and release said individual identifier sequence tract(s), and (v) determining said released sequence tract(s) and using such sequence information to recover the individual antibody member from the library, and (vi) optionally repeating each of (ii) to (v) iteratively for screening and enrichment for an antibody which binds to the antigen of interest, wherein said protease sensitive site is the site for enterokinase, Factor Xa digestion, or endoprotease digestion, said antibody domain is an Fv domain comprising a VH and VL chain, and said identifier sequence tract is C-terminal to the Fv domain.