Patent ID: 9279017
Filing Date: 2016-03-08
CPC Classification: C07K

Claim Text:
1. An antibody fragment obtainable by a method comprising: a) providing a nucleic acid molecule encoding a first antibody variable region or fragment thereof comprising the complementarity determining regions (CDRs) of the first antibody variable region in a source immunoglobulin, wherein the first antibody variable region or fragment thereof is a heavy chain variable region (VH) or a light chain variable region (VL), or a fragment of either of these; b) respectively combining (i) the nucleic acid molecule encoding the first antibody VH or VL region or fragment of either with (ii) a plurality of nucleic acid molecules encoding a diverse population of a second antibody variable region or fragment thereof comprising the CDRs of the second antibody variable region, wherein the second antibody variable region or fragment thereof is a light chain variable region (VL) or a heavy chain variable region (VH), or a fragment of either of these, whereby a population of combined nucleic acid molecules is obtained; c) introducing the population of combined nucleic acid molecules into a display system chosen from a phage display system, a prokaryotic display system, a eukaryotic display system, or an mRNA display system; d) selecting at least one antibody fragment displayed in any one of the display systems of (c) and comprising the VH and VL regions, or a fragment of either or both of these, which specifically binds to an antigen of interest; and e) isolating the at least one antibody fragment selected in (d); wherein the nucleic acid molecule encoding the first antibody variable region or fragment thereof or the nucleic acid molecule encoding the second antibody variable region or fragment thereof is operably linked to a nucleic acid molecule encoding an N-terminal, cis-acting amphipathic polypeptide moiety such that said N-terminal, cis-acting amphipathic polypeptide moiety, when translated, is linked to the N-terminal end of the first or second antibody variable region; wherein the amphipathic polypeptide moiety is chosen from the pro region of any of the following polypeptides: papain, cruzain, thermolysin, cathepsin B, cathepsin L, protease A, protease B, IgA protease, carboxypeptidase Y, or the N2 domain of a filamentous phage; and wherein the source immunoglobulin specifically binds to an antigen of interest, a corresponding antibody fragment of which source immunoglobulin exhibits insufficient soluble recombinant expression.