PROPERTIES AND USES OF EMBRYONIC STEM-CELLS - PROSPECTS FOR APPLICATION TO HUMAN BIOLOGY AND GENE-THERAPY

Embryonic stem cells are pluripotent cells derived from the early mous e embryo that can be propagated stably in the undifferentiated state i n vitro. They retain the ability to differentiate into all cell types found in an embryonic and adult mouse in vivo, and can be induced to d ifferentiate into many cell types in vitro. Exploitation of ES cell te chnology for the creation of mice bearing predetermined genetic altera tions has received widespread attention because of the sophistication that it brings to the study of gene function in mammals. Analysis of c ell differentiation in vitro has also been of value, leading to the id entification of novel bioactive factors and the elucidation of cell sp ecification mechanisms. In this paper, we summarise the features of pl uripotent cell lines and their applications, foreshadowing the impact that these systems may have on human biology. While the isolation of d efinitive human pluripotent cell lines has not yet been achieved, pote ntial applications for these cells in the study of human biology, part icularly cell specification, can be envisaged. Of particular interest is the possibility that human embryonic stem cells with properties sim ilar to mouse embryonic stem cells might provide a generic system for gene therapy.