Antibody producing non-human mammals
Described are transgenic, non-human animals comprising a nucleic acid encoding an immunoglobulin light chain, whereby the immunoglobulin light chain is human, human-like, or humanized. The nucleic acid is provided with a means that renders it resistant to DNA rearrangements and/or somatic hypermutations. In one embodiment, the nucleic acid comprises an expression cassette for the expression of a desired molecule in cells during a certain stage of development in cells developing into mature B cells. Further provided is methods for producing an immunoglobulin from the transgenic, non-human animal.
1. A transgenic mouse immunized with an antigen whose genome comprises a transgene comprising a human immunoglobulin light chain germline V gene segment directly joined to a human immunoglobulin light chain germline J gene segment, so that said joined human V/J gene segments encode a rearranged human immunoglobulin light chain variable region,
wherein the transgene comprises a murine light chain constant region gene segment or is operatively linked to an endogenous light chain constant region gene segment;
wherein a regulatory element that contributes to somatic hypermutation of the light chain variable region is lacking; and
which transgenic mouse contains a repertoire of affinity mature B cells that secrete antibodies that bind said antigen and that have light chains with said rearranged human light chain variable region coupled to a murine light chain constant region, paired with a diversity of immunoglobulin heavy chains.
2. The transgenic mouse of claim 1 , wherein said V gene segment is a human germline Vκ gene segment and said J gene segment is a human germline Jκ gene segment, and said murine immunoglobulin light chain constant region is a κ light chain constant region.
3. The transgenic mouse of claim 1 , wherein expression of said human immunoglobulin light chain V/J gene segments is under the control of a B cell specific promoter.
4. The transgenic mouse of claim 3 , wherein said B cell specific promoter is selected from the group consisting of CD19, CD20, μHC, VpreB1, VpreB2, VpreB3, λ5, Igα, Igß, κLC, λLC and BSAP (Pax5).
5. A transgenic mouse immunized with an antigen, said mouse comprising in its genome a transgene encoding a rearranged human immunoglobulin light chain variable region, wherein said transgene comprises, in a 5′ to 3′ direction,
a promoter selected from the group consisting of CD19, CD20, μHC, VpreB1, VpreB2, VpreB3, λ5, Igα, Igß, κLC, λLC and BSAP (Pax5),
a human or mouse leader, and
a human immunoglobulin light chain germline V gene segment directly joined to a human immunoglobulin light chain germline J gene segment, so that said joined V/J gene segments encode a rearranged human-immunoglobulin light chain variable region,
wherein the transgene comprises a murine light chain constant region gene segment or is operatively linked to an endogenous light chain constant region gene segment;
wherein a regulatory element that contributes to somatic hypermutation of the light chain variable region is lacking; and
which transgenic mouse contains a repertoire of affinity mature B cells that secrete a population of antibodies which bind said antigen comprising said rearranged human light chain variable region coupled to a murine light chain constant region, paired with a diversity of immunoglobulin heavy chains.
6. The transgenic mouse of claim 1 , wherein at least one endogenous immunoglobulin light chain locus is functionally silenced.
7. The transgenic mouse of claim 6 , wherein the endogenous κ light chain locus is functionally silenced.
8. The transgenic mouse of claim 1 , wherein said transgene is located at a locus outside of the endogenous mouse immunoglobulin loci, wherein said locus is resistant to gene silencing.
9. The transgenic mouse of claim 8 , wherein said transgene comprises a murine light chain constant region gene segment and is located at a Rosa-locus.
10. The transgenic mouse of claim 2 , wherein said human germline Vκ gene segment is IKV1-39.
11. The transgenic mouse of claim 2 , wherein said human germline Jκ gene segment is IGKJ1.
12. The transgenic mouse of claim 1 , wherein said murine immunoglobulin light chain constant region is a rat constant region.
13. The transgenic mouse of claim 6 , wherein the endogenous immunoglobulin light chain locus is disrupted.
14. The transgenic mouse of claim 1 , wherein the rearranged human germline V gene segment encodes IGVκ1-39.