Humanized mouse

A humanized mouse is a mouse carrying functioning human genes, cells, tissues, and/or organs. Humanized mice are commonly used as small animal models in biological and medical research for human therapeutics. Immunodeficient mice are often used as recipients for human cells or tissues, because they can relatively easily accept heterologous cells due to lack of host immunity. Traditionally, the nude mouse and severe combined immunodeficiency (SCID) mouse have been used for this purpose, but recently the NOG mouse and the NSG mouse have been shown to engraft human cells and tissues more efficiently than other models. Two mouse strains, called MITRG and MISTRG, were described in which human versions of four genes encoding cytokines important for innate immune cell development are knocked into their respective mouse loci. Such humanized mouse models may be used to model the human immune system in scenarios of health and pathology, and may enable evaluation of therapeutic candidates in an in vivo setting relevant to human physiology.