Animal models and therapeutic molecules
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 humanized antibodies; compositions comprising the antibodies, antibody chains and derivatives, as well as cells, non-human mammals and vectors, suitable for use in the methods.
1. A transgenic mouse having a germline comprising a homozygous immunoglobulin heavy chain (IgH) locus,
wherein said homozygous IgH locus comprises unrearranged human IgH V gene segments, D gene segments and J gene segments at an endogenous IgH locus upstream of an enhancer and a constant (C) region comprising a mouse CH gene segment, wherein said human IgH gene segments join to mouse J/C intron DNA at a chimeric junction upstream of said enhancer,
said human IgH V gene segments, D gene segments and J gene segments are operably linked to said C region to permit expression of an Ig heavy chain polypeptide comprising a human variable region and a mouse constant region,
said unrearranged human IgH V gene segments, D gene segments and J gene segments comprise all the functional human D and JH gene segments and human V gene segments Vh2-5, Vh7-41, Vh-4-4, Vhf-3, Vhf-2 and Vh6-1,
wherein said human JH gene segments comprise a human 3′JH, said 3′ JH being contiguous with human J/C intronic DNA, wherein said 3′JH is less than 2 kb upstream of said chimeric DNA junction,
wherein said mouse J/C intron DNA between said chimeric junction and said enhancer comprises said mouse 129 strain or C57BL/6 strain DNA,
wherein bone marrow B cells of said mouse comprise more pro-B cells than pre-B cells, wherein said pro B cells express CD43 Med B220 Med and said pre B cells express CD43 low B220 high ,
wherein said transgenic mouse expresses immunoglobulin heavy chains comprising human variable regions.
2. The mouse of claim 1 , wherein the mouse expresses a normal relative proportion of serum IgG1, IgG2a, IgG2b and IgM antibodies.
3. The mouse of claim 1 , wherein the mouse expresses (i) serum IgG1 at a concentration of about 25-350 μg/ml; (ii) serum IgG2a at a concentration of about 0-200 μg/ml; (iii) serum IgG2b at a concentration of about 30-800 μg/ml; and (iv) serum IgM at a concentration of about 50-300 μg/ml; or (i) serum IgG1 at a concentration of about 10-600 μg/ml; (ii) serum IgG2a at a concentration of about 0-500 μg/ml; (iii) serum IgG2b at a concentration of about 20-700 μg/ml; and (iv) serum IgM at a concentration of about 50-700 μg/ml; as determined by Ig capture on a plate followed by incubation with anti-mouse isotype-specific labeled antibodies and quantification of Ig using the label.
4. The mouse of claim 1 , wherein the mouse produces a normal proportion or percentage of mature splenic B-cells and/or a normal proportion or percentage of bone marrow B-cell progenitor cells.
5. The mouse of claim 1 , wherein said human 3′ JH gene segments comprise human JH6, and said JH6 is less than 2 kb upstream of said chimeric junction.
6. The mouse of claim 1 , wherein DNA between said chimeric DNA junction and said enhancer comprises said mouse DNA of 129 strain.
7. The mouse of claim 1 , wherein said germline comprises all or part of said mouse heavy chain variable region inverted with respect to said heavy chain constant region.
8. The mouse of claim 1 , wherein said germline comprises all or part of said mouse heavy chain variable region away from said heavy chain constant region.
9. The mouse of claim 1 , wherein said germline comprises all, part or none of said mouse heavy chain variable region.
10. The mouse of claim 1 , wherein said transgenic mouse expresses serum antibodies comprising immunoglobulin heavy chains IgG1, IgG2b and IgM.
11. The mouse of claim 10 , wherein said transgenic mouse expresses serum antibodies further comprising immunoglobulin heavy chain IgG2a.
12. The mouse of claim 1 , wherein less than 10% of IgH chains comprise a mouse variable region.
13. The mouse of claim 12 , wherein said mouse does not express endogenous IgH heavy chain.
14. The mouse of claim 1 , further comprising the human V gene segments Vh2-26, Vhf-24, Vh3-23, Vh3-21, Vh3-20, Vh1-18, Vh3-15, Vh3-13, Vh3-11, Vh3-9, Vhf-8, and Vh3-7.
15. The mouse of claim 1 , further comprising the human V gene segments Vh3-13, Vh3-11, Vh3-9, Vhf-8, and Vh3-7, wherein said transgenic mouse expresses immunoglobulin heavy chains comprising human variable regions Vh3-13, Vh3-11, Vh3-9, Vhf-8, and Vh3-7.
16. The mouse of claim 1 , wherein 75% of IgH chains comprise a mouse variable region.
17. The mouse of claim 1 , wherein both endogenous heavy chain loci are inactive to express endogenous heavy chain polypeptide; said mouse comprises intact endogenous lambda loci to express endogenous lambda light chain polypeptide; and said mouse comprises endogenous kappa loci which are inactive to express endogenous kappa light chain polypeptide.
18. The mouse of claim 1 , wherein said mouse comprises human lambda variable region gene segments at each endogenous lambda locus.
19. The mouse of claim 1 , further comprising the human V gene segments Vh3-13, Vh3-11, Vh3-9, Vhf-8, and Vh3-7, wherein said transgenic mouse expresses immunoglobulin heavy chains comprising human variable regions Vh3-13, Vh3-11, Vh3-9, Vhf-8, and Vh3-7.