ANIMAL MODELS AND THERAPEUTIC MOLECULES - Track 1

Abstract

The invention discloses methods for the generation of chimaeric human-non-human antibodies and chimaeric antibody chains, antibodies and antibody chains so produced, and derivatives thereof including fully humanised antibodies; compositions comprising said antibodies, antibody chains and derivatives, as well as cells, non-human mammals and vectors, suitable for use in said methods.

We claim: 
     
         1 . A method of obtaining an antigen specific antibody or antigen binding fragment thereof, comprising a human immunoglobulin heavy (IgH) chain, wherein said human IgH chain comprises a human IgH chain variable region and a human IgH chain constant region, the method comprising:
 expressing the antibody or antigen binding fragment thereof, from a cell, wherein the cell comprises a nucleic acid encoding said human IgH chain variable region and said human IgH chain constant region of said antibody,   wherein said human IgH chain variable region is of a transgenic mouse contacted with said antigen;   wherein the germline of said mouse has a genome with a homozygous immunoglobulin heavy chain (IgH) locus,   wherein said homozygous IgH locus comprises unrearranged human immunoglobulin heavy chain (IgH) variable region (VH) gene segments comprising one or more human IgH V gene segments, one or more human D gene segments, one or more human JH gene segments and human intronic DNA contiguous with mouse intronic DNA located at an endogenous IgH locus upstream of an enhancer and a constant (C) region comprising an endogenous CH gene segment,   wherein said C region comprises mouse Cμ and said human variable region gene segments are operably linked to said C region to permit rearrangement and expression of chimeric IgM heavy chain polypeptide comprising a human variable region and a mouse μ constant region,   wherein in said transgenic mouse expression of IgH heavy chains comprising endogenous mouse variable regions is reduced or prevented;   wherein said mouse comprises IgH-VDJCμ transcripts encoding said chimeric IgM polypeptide and wherein said IgM comprises human CDR-H3, and said IgH-VDJCμ transcripts comprise transcripts encoding human variable region CDR-H3 lengths of 19 to 22 amino acids,   wherein the mean frequency of said transcripts encoding CDR-H3 lengths selected from the group consisting of 18 and 19 amino acids present in said IgH-VDJC μ transcripts of said mouse is between 5% and 10%.   
     
     
         2 . The method of  claim 1 , the method comprising expressing said antibody or antigen binding fragment thereof from said cell which is a first cell comprising said nucleic acid, wherein said human IgH chain variable region is obtained from a second cell comprising nucleic acid encoding said human IgH chain variable region, and wherein said second cell is of a transgenic mouse contacted with said antigen. 
     
     
         3 . The method of  claim 2 , wherein said second cell is B cell or a hybridoma expressing said human IgH chain variable region. 
     
     
         4 . The method of  claim 2 , wherein said second cell is selected from a plurality of cells comprising nucleic acid encoding antigen-specific human IgH chain variable regions. 
     
     
         5 . The method of  claim 2 , wherein said second cell comprises nucleic acid encoding said human IgH chain variable region and a mouse IgH constant region. 
     
     
         6 . The method of  claim 1 , wherein in said mouse germline said human intronic DNA is contiguous with said mouse intronic DNA at a human DNA/mouse DNA joinder point and wherein said one or more human JH gene segments comprises a 3′-most JH gene segment contiguous with said human intronic DNA, wherein said 3′-most JH gene segment is less than 2 kb upstream of said joinder point. 
     
     
         7 . The method of  claim 6 , wherein in said mouse germline said 3′-most JH gene segment is less than 1 kb upstream of said joinder point. 
     
     
         8 . The method of  claim 6 , wherein said joinder point is upstream of said enhancer. 
     
     
         9 . The method of  claim 8 , wherein in said mouse germline said enhancer is Eμ. 
     
     
         10 . The method of  claim 9 , wherein said mouse germline said Eμ is mouse Eμ. 
     
     
         11 . The method of  claim 6 , wherein in said mouse germline said 3′-most JH gene segment comprises a human JH6 gene segment. 
     
     
         12 . The method of  claim 6 , wherein in said mouse germline DNA said human intronic DNA comprises a truncated human JC intron and said mouse intronic DNA comprises a truncated mouse JC intron. 
     
     
         13 . The method of  claim 6 , wherein in said mouse germline DNA said truncated mouse JC intron comprises mouse 129 strain DNA, optionally 129Sv strain DNA. 
     
     
         14 . The method of  claim 1 , wherein said mouse germline comprises all or part of a mouse heavy chain variable region inverted with respect to said heavy chain constant region or part of a mouse heavy chain variable region absent to render expression of Ig heavy chains comprising a mouse variable region reduced or prevented. 
     
     
         15 . The method of  claim 6 , wherein said mouse is functional to produce antibody isotypes IgM and IgG specific for said antigen each isotype comprising a human heavy chain variable region. 
     
     
         16 . The method of  claim 1 , the method further comprising
 recovering said antibody or antigen-binding fragment thereof.   
     
     
         17 . The method of  claim 1 , the method further comprising
 recovering said nucleic acid encoding said human IgH chain variable region.   
     
     
         18 . The method of  claim 1 , further comprising
 recovering said cell expressing said antibody or antigen-binding fragment thereof.   
     
     
         19 . The method of  claim 1 , wherein prior to said expressing the method comprises providing said cell. 
     
     
         20 . The method of  claim 1 , further comprising providing a pharmaceutical composition comprising said antigen-specific antibody or anigen-binding fragment thereof and a pharmaceutically acceptable carrier or excipient. 
     
     
         21 . The method of  claim 1 , further comprising providing said antibody or antigen-binding fragment thereof to a human subject. 
     
     
         22 . The method of  claim 1 , wherein the human IgH variable region of the antibody or fragment thereof comprises a CDR-H3 length of 19 to 22 amino acids. 
     
     
         23 . The method of  claim 1 , wherein said antigen-specific antibody or antigen binding fragment thereof is a domain antibody. 
     
     
         24 . The method of  claim 1 , wherein said antigen-specific antibody or antigen binding fragment thereof is a monoclonal antibody or an antigen binding fragment thereof. 
     
     
         25 . The method of  claim 1 , wherein said antigen-specific antibody or antigen binding fragment thereof is a neutralizing antibody or antigen binding fragment thereof. 
     
     
         26 . The method of  claim 1 , wherein in said mouse germline said unrearranged human IgH VH gene segments comprise human V6-1, VII-1-1, V1-2, VIII-2-1, V1-3, V4-4 and V2-5 gene segments. 
     
     
         27 . The method of  claim 1 , wherein in said mouse germline said unrearranged human IgH VH gene segments comprise all of the human V, D and J gene segments.