The present teachings relate to methods of screening for a therapeutic agent, selecting a treatment and monitoring a treatment for a human disease or infection and methods for producing a mouse model for human disease or infection wherein the mouse has a functioning human immune system. The method includes administering a test substance to an immunocompromised NOD/SCID mouse with a reconstituted human immune system and is also engrafted with a substance containing a diseased or infectious cell derived from a human diseased or infected patient and a step of assessing improvement in the disease or infection of the mouse and/or to monitor a side effect of the test substance.
