In Vivo Methods to Analyze Cell Origins, Migrations, Homing, and Interactions in the Blood, Vascular, and Immune Systems of the Avian and Mammalian Em

In vivo experimental approaches that have been designed to study the ontogeny of the hematopoietic system in higher vertebrates are described in the present chapter. The avian embryo is directly available to manipulations in ovo during gastrulation and organogenesis. This permissiveness has led to the design of various approaches that provided crucial insights into the ontogeny of the hematopoietic system, particularly regarding traffic of progenitors between different compartments. In contrast, experimental manipulation of the developing mouse in utero is possible only during the second half of gestation, that is, the fetal period. This approach has been very useful in understanding how the immune system learns to distinguish self from nonself.