The human immune system in hu-PBL-SCID mice.

Severe combined immunodeficiency (SCID) mice can be stably grafted with human peripheral blood lymphocytes, creating hu-PBL-SCID chimeras; essentially, these are mice with a human immune system. Here, Magdalena Tary-Lehmann, Andrew Saxon and Paul Lehmann discuss the immunobiology of these chimeras. The authors propose that hu-PBL-SCID chimerism evolves in two phases. During the first three weeks after grafting, many of the injected cells survive and the human immune system is functional. Subsequently, anti-mouse-reactive clones are selected and the immune system becomes nonfunctional. The implications of this scenario for the utilization of the hu-PBL-SCID model are discussed.