ISOLATION OF ES-LIKE CELL-LINES FROM OVINE AND CAPRINE PREIMPLANTATION EMBRYOS

Intact ovine and caprine d7/d8 blastocysts and inner cell masses, or e mbryonic discs (d10/d11) isolated mechanically were cultured under dif ferent conditions in order to establish which of the feeder cell types , medium supplements or developmental stages used are most suitable fo r the isolation of ES-like cells in both species. Subcultures were mos t successful with isolated embryonic discs on inactivated bovine fetal liver fibroblasts, but ES-like cells did nor develop beyond the 44th passage. Morphological ES-like cells were analyzed fluorescence micros copically after treatment with monoclonal antibodies against cytoskele ton markers or after marking with DBA- and PNA-agglutinin. Cells were Cytokeratin 18- and DBA-negative, but vimentin- and PNA-positive. In s uspension culture these cells developed embryoid body-like structures, and following induced differentiation tubular structures and epitheli al-, fibroblast-, and neuron-like cells. ES-like cells (> 10 passages) were analysed in the nuclear transfer assay. Initial development coul d be initiated, bur development beyond the 12cell stage did not occur.