Generation of xenogeneic antibodies

Abstract

The subject invention provides non-human mammalian hosts characterized by inactivated endogenous Ig loci and functional human Ig loci for response to an immunogen to produce human antibodies or analogs thereof. The hosts are produced by repetitive transformations of embryonic stem cells by homologous recombination, preferably in conjunction with breeding. Different strategies are employed for recombination of the human loci randomly or at analogous host loci.

1 - 25 . cancelled.  
     
     
         26 . A transgenic mouse whose genome comprises a DNA fragment consisting essentially of the DNA sequence of human chromosome 14 from the D segment genes of the human immunoglobulin heavy chain locus, continuing through the J segment genes and the constant region genes through Cμ of that locus, wherein said DNA fragment does not include a gamma constant region, and wherein said DNA fragment is operably linked to at least one human V segment gene.  
     
     
         27 . A transgenic mouse whose genome comprises a DNA fragment of a human immunoglobulin heavy chain locus, the fragment consisting essentially of a SpeI-SpeI fragment commencing at the VH6 gene and continuing through the human D segment genes, human J segment genes and human constant region genes and into the Cδ gene of that locus, wherein said SpeI-SpeI fragment does not include a gamma constant region.  
     
     
         28 . A transgenic mouse whose genome comprises a DNA fragment of a human immuniglobulin heavy chain locus the fragment consisting essentially of a SpeI-SpeI fragment commencing at the VH6 gene and continuing through the human D segment genes, human J segment genes and through the human Cμ constant region gene said SpeI-SpeI fragment terminating within the Cδ gene of that locus.  
     
     
         29 . A transgenic mouse comprising a modified genome, the modifications comprising an inserted human DNA sequence consisting essentially of 85-100 kb of human chromosome 14, extending from within the V segment genes of the human immunoglobulin gene locus at a position 3′ of a SpeI restriction site through the human Cμ constant region gene.  
     
     
         30 . A transgenic mouse comprising a modified genome, the modifications comprising an inserted human DNA sequence consisting essentially of between 85-100 kb extending from the human D segment genes through the human Cμ constant region, wherein the DNA sequence is operably linked to at least one human V segment gene.  
     
     
         31 . The transgenic mouse according to any one of claims  26 - 30 , further comprising an endogenous immunoglobulin heavy chain locus wherein all of the J segment genes of the locus are replaced by a selectable marker.  
     
     
         32 . A transgenic mouse and its progeny, wherein the somatic and germ cells comprise: 
 (a) inactivated endogenous immunoglobulin loci in which all of the J segment genes are deleted to prevent rearrangement and to prevent formation of a transcript of a rearranged locus, wherein said transgenic mouse and progeny lack expression of endogenous immunoglobulin heavy chains; and    (b) a DNA fragment consisting essentially of a DNA sequence of human chromosome 14 from the D segment genes of the human immunoglobulin heavy chain locus, continuing through the J segment genes and the constant region genes through Cμ of that locus, wherein said DNA fragment does not include a gamma constant region, and wherein said DNA fragment is operably linked to at least one human V segment gene.    
     
     
         33 . The transgenic mouse according to any one of claims  26 - 30  or  32 , and its progeny, wherein the B cells of said transgenic mouse and progeny express a human IgM heavy chain.  
     
     
         34 . The transgenic mouse according to  claim 31 , and its progeny, wherein the B cells of said transgenic mouse and progeny express a human IgM heavy chain.  
     
     
         35 . A method for producing an IgM antibody specific for an antigen of interest, said antibody comprising a human IgM heavy chain, comprising the step of immunizing a transgenic mouse according to any one of claims  26 - 30  or  32  with said antigen of interest and isolating the IgM antibody specific for said antigen.  
     
     
         36 . A method for producing an IgM antibody specific for an antigen of interest, said antibody comprising a human IgM heavy chain, comprising the step of immunizing a transgenic mouse according to  claim 31  with the antigen of interest and isolating the IgM heavy chain.