Animal models and therapeutic molecules

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.

1 . (canceled) 
     
     
         2 . A transgenic rodent having a genetically altered genome comprising
 (i) a chimeric immunoglobulin heavy chain locus comprising unrearranged human IgH variable (V) region DNA positioned at an endogenous IgH locus upstream of a rodent constant (C) segment, the human IgH V region DNA comprising one or more human IgH variable (VH) segments, one or more human D segments and one or more human heavy chain J (JH) segments; and   (ii) an inversion or deletion of all or part of the rodent IgH variable (V) region from its position in an intact endogenous IgH locus sufficient to reduce the amount of heavy chain polypeptide comprising a rodent V region and a rodent C region present in serum of said trangenic rodent relative to the amount of heavy chain polypeptide comprising a rodent V region and a rodent C region present in serum of a rodent comprising homozygous intact endogenous immunoglobulin heavy chain loci;   wherein said transgenic rodent is functional to undergo human V region rearrangement and express a chimeric heavy chain polypeptide comprising a human V region and a rodent C region;   wherein said transgenic rodent is capable of germline transmission of the chimeric immunoglobulin heavy chain locus to a progeny rodent thereof.   
     
     
         3 . The rodent of  claim 2 , wherein said transgenic rodent is homozygous for said deletion or said inversion. 
     
     
         4 . The rodent of  claim 2 , wherein said transgenic rodent is homozygous for said chimeric immunoglobulin heavy chain locus. 
     
     
         5 . The rodent of  claim 2 , wherein said transgenic rodent is substantially non-functional to express a fully rodent immunoglobulin heavy IgH chain polypeptide. 
     
     
         6 . The rodent of  claim 2 , wherein the rodent is a mouse or a rat. 
     
     
         7 . The rodent of  claim 2 , said rodent being a subsequent generation rodent having an altered genome comprising
 (i) said chimeric immunoglobulin heavy chain locus, and   (ii) said inversion or deletion,   
       wherein said subsequent generation rodent is functional to undergo human V region rearrangement and express a chimeric heavy chain polypeptide comprising a human V region and a rodent C region; and 
       wherein said subsequent generation rodent is capable of germline transmission of said chimeric immunoglobulin heavy chain locus to its offspring. 
     
     
         8 . The progeny rodent of  claim 7 , wherein said rodent is substantially non-functional to express a fully rodent immunoglobulin heavy IgH chain polypeptide. 
     
     
         9 . The progeny rodent of  claim 7 , wherein said rodent is a mouse or a rat. 
     
     
         10 . The rodent of  claim 7 , wherein said transgenic rodent is homozygous for said deletion or said inversion. 
     
     
         11 . The rodent of  claim 7 , wherein said transgenic rodent is homozygous for said chimeric immunoglobulin heavy chain locus. 
     
     
         12 . The rodent of  claim 7 , wherein said transgenic rodent is substantially non-functional to express a fully rodent immunoglobulin heavy IgH chain polypeptide. 
     
     
         13 . A method of isolating a polypeptide encoding a human variable region of an antibody or nucleic acid encoding a polypeptide comprising human variable region of an antibody, the method comprising:
 (a) providing the transgenic rodent of  claim 2  or  claim 7 , immunized with a target antigen and comprising chimeric immunoglobulin polypeptide chains and/or chimeric antibodies; and   (b) isolating from the immunized rodent of step (a) one or more of: (i) an antibody that specifically binds to said antigen, (ii) a human variable region polypeptide specific for said antigen; (iii) a cell that produces an antibody specific for said antigen; and (iv) nucleic acid comprising a region encoding a human variable region of an antibody that specifically binds said antigen.   
     
     
         14 . The method of  claim 13 , further comprising the step of subjecting said isolated antibody of step (b) to affinity maturation to provide an affinity matured antibody. 
     
     
         15 . The method of  claim 13 , further comprising the step of isolating a human variable region polypeptide which specifically binds said antigen, wherein said human variable region polypeptide optionally comprises a domain antibody. 
     
     
         16 . The method of  claim 13 , said cell being selected from the group consisting of: an ES cell and a B-cell. 
     
     
         17 . The method of  claim 16 , further comprising the step of preparing a hybridoma from said B cell to thereby provide a B cell hybridoma or preparing a stem cell line from said ES cell to thereby provide a stem cell line. 
     
     
         18 . The method of  claim 13 , wherein said nucleic acid encoding said human variable region is joined to a nucleic acid encoding a human constant region to form a nucleic acid encoding an immunoglobulin heavy chain comprising a human variable region and a human constant region. 
     
     
         19 . A method of generating a subsequent generation transgenic rodent, the method comprising breeding a rodent of  claim 2  or  7 , and selecting an offspring. 
     
     
         20 . The method of  claim 19 , wherein each said bred rodent and said offspring is homozygous for said deletion or said inversion. 
     
     
         21 . The method of  claim 19 , wherein each said bred rodent and said offspring is homozygous for said deletion. 
     
     
         22 . The method of  claim 19 , wherein each bred rodent and said offspring is homozygous for said chimeric immunoglobulin heavy chain locus.