Genetically modified mice and engraftment

Inventors

Stevens, Sean • Murphy, Andrew J. • Flavell, Richard • Eynon, Elizabeth • Galan, Jorge • Willinger, Tim • Manz, Markus • Rongvaux, Anthony • Yancopoulos, George D.

Assignees

Institute for Research in Biomedicine IRB • Yale University • Regeneron Pharmaceuticals Inc

Abstract

A mouse with a humanization of the mIL-3 gene and the mGM-CSF gene, a knockout of a mRAG gene, and a knockout of a mIl2rg subunit gene; and optionally a humanization of the TPO gene is described. A RAG/Il2rg KO/hTPO knock-in mouse is described. A mouse engrafted with human hematopoietic stem cells (HSCs) that maintains a human immune cell (HIC) population derived from the HSCs and that is infectable by a human pathogen, e.g., S. typhi or M. tuberculosis is described. A mouse that models a human pathogen infection that is poorly modeled in mice is described, e.g., a mouse that models a human mycobacterial infection, wherein the mouse develops one or more granulomas comprising human immune cells. A mouse that comprises a human hematopoietic malignancy that originates from an early human hematopoietic cells is described, e.g., a myeloid leukemia or a myeloproliferative neoplasia.

Core Innovation

The disclosure relates to genetically modified, immune-compromised mice in which each of a first mouse and a second mouse are null for recombination-activating gene 2 (RAG2) and null for a mouse interleukin 2 receptor gamma (IL-2Rg) gene. The genetically modified first mouse comprises an engraftment of human CD34+ hematopoietic cells and replaces each allele of the mouse thrombopoietin (TPO) gene with a human TPO gene at the mouse TPO gene locus, and does not express mouse TPO.

Engrafting human CD34+ hematopoietic cells isolated from the genetically modified first mouse into the second RAG2-null and IL-2Rg-null mouse results in a statistically significant increase in human CD45+ hematopoietic cells in the bone marrow of the second mouse relative to a comparison RAG2-null IL-2Rg-null mouse engrafted with human CD34+ hematopoietic cells isolated from a mouse TPO-expressing mouse.

The disclosure also covers genetically modified mice where, in addition to the TPO replacement, mouse interleukin 3 (IL-3) and mouse granulocyte-macrophage colony-stimulating factor (GM-CSF) are replaced with human IL-3 and human GM-CSF at the respective loci. These genetically modified immune-compromised mice are described as maintaining human immune cell populations after engraftment and enabling improved human immune responses, including human myeloid/macrophage differentiation in the lung and enhanced inflammatory and mucosal immune responses.

Claims Coverage

The partial content includes two independent claims, a method claim and a second-mouse claim. Across the independent claims, the coverage centers on immune-compromised RAG2-null/IL-2Rg-null mouse systems with human TPO knock-in and an engraftment-based increase in human CD45+ hematopoietic cells in bone marrow relative to mouse-TPO-expressing controls; additional refinements humanize IL-3 and GM-CSF loci.

The independent claims focus on an immune-compromised RAG2-null/IL-2Rg-null engraftment system using human CD34+ hematopoietic cells from a first mouse with human TPO replacement, yielding a statistically significant increase in human CD45+ hematopoietic cells in the second mouse bone marrow versus a mouse-TPO-expressing control. The remaining refinements include human IL-3 and human GM-CSF replacement at the respective loci.

Stated Advantages

Documented Applications