The method of making the human liver cell increase with in vivo the humariruaseto acetic acid hydrase (Fah) furthermore making use of the immunity incomplete mouse which deficiency has been done, is stated in this bill. The said method includes, the said immunity incompletion and the step which transplants the human liver cell to the Fah deficiency mouse and the step which makes the said liver cell increase and, the step which extracts the said human liver cell which is made to increase and. In addition as for the said method, the second or tertiary or quaternary, or it makes, also the continual transplantation of the said human liver cell to the additional following mouse possible. In addition, homo- connection union deficiency or point mutation is included in Fah, Rag2, and the Il2rg gene, also the mutant mouse offers.フマリルアセト酢酸ヒドラーゼ(Fah)がさらに欠損している免疫不全マウスを用いて、生体内でヒト肝細胞を増大させる方法を、本明細書に記載する。該方法は、該免疫不全およびFah欠損マウスにヒト肝細胞を移植するステップと、該肝細胞を増大させるステップと、増大させた該ヒト肝細胞を採取するステップと、を含む。該方法はまた、二次、または三次、または四次、または追加次のマウスへの、該ヒト肝細胞の連続移植も可能にする。また、Fah、Rag2、およびIl2rg遺伝子において、ホモ接合体欠失または点変異を含む、変異体マウスも提供する。
