Derivation and Differentiation of Human Embryonic Germ Cells

Human EG cells can be derived from PGCs by using methods similar to those used to derive mouse EG cultures. Like mouse ES and EG cells, human EG cells require LIF for proliferation as undifferentiated stem cells. Unlike mouse EG cells, however, human EG cells do not readily lose their dependence on exogenous cytokines and factors supplied by the feeder layer, and they have a higher frequency of spontaneous differentiation into EBs. Although EBs are a loss to the pluripotent stem cell population, they are a source of cells expressing markers of mature cellular phenotypes, as well as their presumed progenitors and precursors. Cells that retain a high capacity for cell proliferation and express makers of multiple lineages can be isolated from EBs, and can be used in a variety of in vitro and in vivo differentiation paradigms. The current challenges are to match individual EBD cultures to desired endpoints, and to enrich or purify populations of cells within EBD cultures to more specifically address biological requirements.