The need for humanized mouse models is largely driven by the fact that many findings from conventional animal models do not apply to humans due to the intrinsic differences between species.Humanized mice with functional human hematopoietic and lymphoid systems are particularly useful in the study of pathogens and therapies that specifically target human lymphohematopoietic cells.Over the last two decades,numerous efforts have been devoted towards the development of such humanized mouse models.