Immunodeficient mice expressing human interleukin 15

Abstract

An immunodeficient mouse is provided which is useful as a model of functions and regulation of human natural killer (NK) cells and other interleukin 15 (IL-15)-dependent cell populations and processes in studies of human immunity, cancer, infectious diseases, and other areas. According to specific aspects, an immunodeficient mouse is provided which is genetically modified to express human interleukin 15, wherein the mouse does not have or produce functional mouse natural killer cells, and wherein the mouse is modified to include human natural killer cells. Methods of identifying anti-tumor activity of a test substance using a mouse of the present invention are described along with methods of making the mouse.

1 . An immunodeficient mouse genetically modified to include a nucleotide sequence encoding human interleukin-15 (hu-IL-15) in its genome, wherein the mouse expresses the hu-IL-15. 
     
     
         2 . The immunodeficient mouse of  claim 1 , wherein the mouse has an absence of functional endogenous mouse natural killer (NK) cells. 
     
     
         3 . The immunodeficient mouse of  claim 1  or  2 , wherein the mouse is IL-2RG null such that it lacks a functional endogenous IL-2RG gene and lacks functional endogenous mouse NK cells. 
     
     
         4 . The immunodeficient mouse of any one of the preceding claims, wherein the immunodeficient mouse is a genetically modified NSG, NRG or NOG mouse. 
     
     
         5 . The immunodeficient mouse of any one of the preceding claims, further comprising: human hematopoietic stem cells, human peripheral blood mononuclear cells (PBMCs), human NK cells, human NK cell line cells, or a combination of any two or more thereof. 
     
     
         6 . The immunodeficient mouse of any one of the preceding claims, wherein the mouse comprises human natural killer cells and the human natural killer cells are produced in the mouse by differentiation of human hematopoietic stem cells in the mouse or wherein the human natural killer cells are maintained and/or produced in the mouse following administration of PBMCs containing human natural killer cells. 
     
     
         7 . The immunodeficient mouse of any one of the preceding claims, further comprising a human xenograft comprising human tumor cells. 
     
     
         8 . A method of identifying anti-tumor activity of a test substance, comprising:
 providing an immunodeficient mouse according to any one of  claims 1  to  6 ;   administering human tumor cells to the immunodeficient mouse, wherein the human tumor cells form a solid or non-solid tumor in the genetically-modified, immunodeficient mouse;   administering a test substance to the immunodeficient mouse; and   assaying a response of the solid or non-solid tumor to the test substance, wherein an inhibitory effect of the test substance on the tumor and/or tumor cells identifies the test substance as having anti-tumor activity.   
     
     
         9 . The method of  claim 8 , further comprising comparing the response to a standard to determine the effect of the test substance on the human tumor cells, wherein an inhibitory effect of the test substance on the human tumor cells identifies the test substance as having anti-tumor activity. 
     
     
         10 . The method of  claim 8  or  9 , wherein the test substance comprises an immunotherapeutic agent. 
     
     
         11 . The method of any one of  claims 8  to  10 , wherein the test substance is an immune checkpoint inhibitor. 
     
     
         12 . The method of  claim 11 , wherein the immune checkpoint inhibitor is a PD-1 inhibitor, PD-L1 inhibitor, or CTLA-4 inhibitor. 
     
     
         13 . The method of  claim 11  or  12 , wherein the immune checkpoint inhibitor is atezolizumab, avelumab, durvalumab, ipilimumab, nivolumab, or pembrolizumab, or the immune checkpoint inhibitor comprises an antigen-binding fragment of any one of the foregoing. 
     
     
         14 . The method of any one of  claims 8  to  13 , wherein the test substance comprises an antibody. 
     
     
         15 . The method of any one of  claims 8  to  14 , wherein the test substance comprises an anti-cancer agent. 
     
     
         16 . A method of making a genetically-modified, immunodeficient humanized mouse model, comprising:
 providing an immunodeficient mouse according to any one of  claims 1  to  4 ; and   administering human hematopoietic stem cells, human peripheral blood mononuclear cells (PBMCs), human NK cells, human NK cell line cells, or a combination of any two or more thereof, to the immunodeficient mouse.   
     
     
         17 . The method of  claim 16 , further comprising conditioning the immunodeficient mouse to reduce mouse hematopoietic cells of the mouse prior to administering human hematopoietic stem cells, human peripheral blood mononuclear cells (PBMCs), human NK cells, human NK cell line cells, or a combination of any two or more thereof. 
     
     
         18 . The method of  claim 17 , wherein conditioning the immunodeficient mouse to reduce mouse hematopoietic cells of the mouse comprises irradiating the genetically-modified, immunodeficient mouse and/or administering a radiomimetic drug to the genetically-modified, immunodeficient mouse. 
     
     
         19 . The method of  claim 18 , wherein no conditioning to reduce mouse hematopoietic cells of the mouse is performed prior to administering human hematopoietic stem cells, human peripheral blood mononuclear cells (PBMCs), human NK cells, human NK cell line cells, or a combination of any two or more thereof. 
     
     
         20 . The method of any one of  claims 16  to  19 , further comprising administering a human xenograft comprising human tumor cells to the immunodeficient mouse. 
     
     
         21 . A genetically-modified, immunodeficient mouse substantially as described or shown herein. 
     
     
         22 . A method of making a genetically-modified, immunodeficient humanized mouse model substantially as described or shown herein. 
     
     
         23 . A method of identifying anti-tumor activity of a test substance substantially as described or shown herein.