DERIVATION AND CHARACTERIZATION OF PUTATIVE PLURIPOTENTIAL EMBRYONIC STEM-CELLS FROM PREIMPLANTATION RABBIT EMBRYOS

We have derived putative embryonic stem (ES) cell lines from preimplan tation rabbit embryos and report here their initial characterization. Two principal cell types emerged following serial passage of explanted embryos, and each has subsequently given rise to immortalized cell li nes. One cell type has morphology identical to primary outgrowths of t rophectoderm, is strictly feeder-cell dependent, and spontaneously for ms trophectodermal vesicles at high cell density. The second type appe ars to represent pluripotent ES cells derived from the inner cell mass as evidenced by 1) ability to grow in an undifferentiated state on fe eder layers, 2) maintenance of a predominantly normal karyotype throug h serial passage (over 1 year), and 3) ability to form embryoid bodies , which form terminally differentiated cell types representative of ec toderm, mesoderm, and endoderm. These ES cells may ultimately be suita ble for introduction of germline mutations (via homologous recombinati on). The rabbit's size, reproductive capability, and well-characterize d physiology make it suitable for a wide range of investigations, part icularly for development of large animal models of human disease. (C) 1993 Wiley-Liss, Inc.