Humanized Mouse Technology
Humanized mice refer to mice stably reconstituted or engrafted with human tissues/cells, such as human blood, immune and liver cells. Humanized mice with a reconstituted human immune system are constructed by engrafting immunodeficient mice with human hematopoietic (or blood) stem cells (HSC), which then give rise to all human blood lineage cells throughout the lifetime of the mice. Similarly, to reconstitute other tissues/organs with human cells, appropriate human tissue stem cells are engrafted into suitable mouse recipients.
For the past three decades, there has been a long-standing effort to reconstitute severe combined immunodeficient (scid) mice, which lack their own T and B lymphocytes, with human immune cells. Early approaches were unsuccessful; however, because of poor implantation efficiency, or rapid disappearance of human T and B cells from recipient mice. This problem has been solved and stable and long-term engraftment has been achieved when mice that lack T, B and natural killer (NK) cells were used as recipients.