PRODUCTION OF PHARMACEUTICAL PROTEINS IN EGGS

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The aim of this research is to establish chicken embryonic stem cell cultures with the goal of developing genetically modified chickens that produce pharmaceutical proteins in their eggs. Currently chimeras can be obtained by injecting freshly isolated stage X embryos into a recipient stage X embryo. Long term cultures can be established from stage X blastodermal cells but it has been difficult to obtain chimeras from these longer term cultures. At stage X, the blastodermal cells are heterogeneous with certain regions of the embryo having more pluripotent cells than others. It is postulated that cells from earlier embryos (stage V-VII) are less differentiated which makes them better candidates for the derivation of an embryonic stem cell line. Hens will be treated with arginine vasopressin to induce premature ovipostion at stage V-VII. Different culture conditions will be evaluated for their potential to maintain the blastodermal cells in an undifferentiated state. Cultures which are positive for AP, SSEA-1 and EMA-1, will produce ectodermal, mesodermal and endodermal derivatives in vitro and are telomerase positive will be tested for their potential to contribute to somatic chimerism. In phase 2 contributions to the germline will be evaluated. PROPOSED COMMERCIAL APPLICATIONS: The technology can be applied to protein production in several ways. Firstly, pluripotential cells can be engineered to produce protein in the oviduct and liver; these proteins will be deposited in the albumen and the yolk, respectively. Secondly, the proteins can be produced by chimeras, which contain both genetically altered and normal cells, and in stocks derived from transgenic founders. Thirdly, human polyclonal immunoglobulins can be produced by chicken B cells by transcribing human DNA in germline configuration to generate antibody diversity.