Genetically modified major histocompatibility complex mice
The invention provides genetically modified non-human animals that express chimeric human/non-human MHC I polypeptide and/or human or humanized β2 microglobulin polypeptide, as well as embryos, cells, and tissues comprising the same. Also provided are constructs for making said genetically modified animals and methods of making the same. Methods of using the genetically modified animals to study various aspects of the human immune system are provided.
1. A mouse comprising in its genome:
(i) at an endogenous mouse classical MHC I locus, a first nucleotide sequence encoding a chimeric human/mouse MHC I polypeptide,
wherein the first nucleotide sequence comprises from 5′ to 3′: a nucleic acid sequence encoding α1, α2, and α3 domains of a human classical MHC I polypeptide operably linked to a nucleic acid sequence encoding transmembrane and cytoplasmic domains of an endogenous mouse classical MHC I polypeptide,
wherein the nucleic acid sequence encoding α1, α2, and α3 domains of a human classical MHC I polypeptide replaces the sequence encoding α1, α2, and α3 domains of the mouse classical MHC I polypeptide at the endogenous mouse classical MHC I locus, and
wherein the first nucleotide sequence is operably linked to an endogenous mouse MHC I regulatory element and an MHC class I leader encoding sequence; and
(ii) at an endogenous mouse β2 microglobulin locus, a second nucleotide sequence encoding a functional humanized or human β2 microglobulin polypeptide,
wherein the second nucleotide sequence comprises from 5′ to 3′:
(a) a nucleic acid comprising a sequence set forth in exon 1 of an endogenous mouse β2 microglobulin gene operably linked to a nucleic acid comprising sequences set forth in exon 2, exon 3, and exon 4 of a human β2 microglobulin gene, or
(b) a nucleic acid comprising sequences set forth in exon 1, exon 2, exon 3, and exon 4 of a human β2 microglobulin gene, and
wherein the second nucleotide sequence is operably linked to an endogenous mouse β2 microglobulin regulatory element,
wherein the mouse expresses, on the surface of nucleated cells, the chimeric human/mouse MHC I polypeptide non-covalently associated with the functional human or humanized β2 microglobulin polypeptide.
2. The mouse of claim 1 , wherein the mouse does not express an extracellular domain of an endogenous mouse classical MHC I polypeptide and a functional endogenous mouse β2 microglobulin polypeptide from the endogenous mouse classical MHC I and β2 microglobulin loci.
3. The mouse of claim 1 , wherein the endogenous mouse classical MHC I locus is a mouse H-2K locus, and the endogenous mouse classical MHC I polypeptide is an endogenous mouse H-2K polypeptide.
4. The mouse of claim 1 , wherein the human classical MHC I polypeptide is an HLA-A polypeptide or an HLA-B polypeptide.
5. The mouse of claim 4 , wherein the human classical MHC I polypeptide is an HLA-A polypeptide.
6. The mouse of claim 1 , wherein the second nucleotide sequence comprises from 5′ to 3′:
a nucleic acid comprising a sequence set forth in exon 1 of an endogenous mouse β2 microglobulin gene operably linked to a nucleic acid comprising sequences set forth in exon 2 to exon 4 of a human β2 microglobulin gene.
7. The mouse of claim 3 , wherein the human classical MEW I polypeptide is an HLA-A polypeptide or an HLA-B polypeptide.
8. The mouse of claim 7 , wherein the human classical MHC I polypeptide is an HLA-A polypeptide.
9. The mouse of claim 8 , wherein the second nucleotide sequence comprises from 5′ to 3′:
a nucleic acid comprising a sequence set forth in exon 1 of an endogenous mouse β2 microglobulin gene operably linked to a nucleic acid comprising sequences set forth in exon 2 to exon 4 of a human β2 microglobulin gene.
10. The mouse of claim 6 , wherein the sequences set forth in exon 2 to exon 4 of a human β2 microglobulin gene replace at the endogenous mouse β2 locus endogenous sequences set forth in exon 2 to exon 4 of the endogenous mouse β2 microglobulin gene.
11. The mouse of claim 9 , wherein the sequences set forth in exon 2 to exon 4 of a human β2 microglobulin gene replace at the endogenous mouse β2 locus endogenous sequences set forth in exon 2 to exon 4 of the endogenous mouse β2 microglobulin gene.
12. A method of making a genetically modified mouse, comprising
(A) replacing at an endogenous mouse classical MHC I locus a nucleic acid sequence encoding α1, α2, and α3 domains of an endogenous mouse classical MHC I polypeptide with a nucleic acid sequence encoding α1, α2, and α3 domains of a human classical MHC I polypeptide to form a first nucleotide sequence that encodes a chimeric human/mouse MHC I polypeptide,
wherein the first nucleotide sequence comprises from 5′ to 3′: a nucleic acid sequence encoding α1, α2, and α3 domains of a human classical MHC I polypeptide operably linked to an endogenous nucleic acid sequence encoding transmembrane and cytoplasmic domains of the endogenous mouse classical MHC I polypeptide, and
wherein the first nucleotide sequence is operably linked to an endogenous mouse MHC I regulatory element and an MHC class I leader encoding sequence, and
(B) modifying an endogenous mouse β2 microglobulin locus by:
(a) replacing at the endogenous mouse β2 microglobulin locus a nucleic acid comprising sequences set forth in exon 2, exon 3, and exon 4 of an endogenous mouse β2 microglobulin gene with a nucleic acid comprising sequences set forth in exon 2, exon 3, and exon 4 of a human β2 microglobulin gene to form a second nucleotide sequence that encodes a functional humanized β2 microglobulin polypeptide, wherein the second nucleotide sequence comprises from 5′ to 3′: a nucleic acid comprising a sequence set forth in exon 1 of the endogenous mouse β2 microglobulin gene operably linked to a nucleic acid comprising sequences set forth in exon 2, exon 3, and exon 4 of the human β2 microglobulin gene,
wherein the second nucleotide sequence is operably linked to an endogenous mouse β2 microglobulin regulatory element, or
(b) introducing at the endogenous mouse β2 microglobulin locus a nucleic acid comprising a human β2 microglobulin gene to form a third nucleotide sequence that encodes a functional human β2 microglobulin polypeptide, wherein the third nucleotide sequence comprises from 5′ to 3′: a nucleic acid comprising sequences set forth in exon 1, exon 2, exon 3, and exon 4 of a human β2 microglobulin gene,
wherein the third nucleotide sequence is operably linked to an endogenous mouse β2 microglobulin regulatory element, and
wherein the mouse expresses, on the surface of nucleated cells, the chimeric human/mouse MEW I polypeptide non-covalently associated with the functional humanized or human β2 microglobulin polypeptide.
13. The method of claim 12 , wherein the steps of replacing in (A) and modifying in (B) are in a single embryonic stem (ES) cell and the method further comprises introducing the single ES cell into an embryo to make a mouse.
14. The method of claim 12 , wherein the endogenous mouse classical MHC I locus is a mouse H-2K locus, and the endogenous mouse classical MHC I polypeptide is an endogenous mouse H-2K polypeptide.
15. The method of claim 12 , wherein the human classical MEW I polypeptide is an HLA-A polypeptide or an HLA-B polypeptide.
16. The method of claim 15 , wherein the human classical MHC I polypeptide is an HLA-A polypeptide.
17. The method of claim 14 , wherein the human classical MHC I polypeptide is an HLA-A polypeptide.
18. The method of claim 12 , wherein replacing at an endogenous mouse β2 microglobulin locus a nucleic acid comprising sequences set forth in exon 2, exon 3, and exon 4 of an endogenous mouse β2 microglobulin gene with a nucleic acid comprising sequences set forth in exon 2, exon 3, and exon 4 of a human β2 microglobulin gene comprises
replacing at an endogenous mouse β2 microglobulin locus a nucleic acid comprising a sequence set forth in exon 2 to exon 4 of an endogenous mouse β2 microglobulin gene with a nucleic acid comprising a sequence set forth in exon 2 to exon 4 of a human β2 microglobulin gene.