Duck embryonic derived stem cell lines for the production of viral vaccines

A process of production of a virus which comprises replicating a virus in cells of an avian cell line wherein said cell line has been obtained by a method comprising the following steps:

• a) isolating a duck embryo around oviposition;
• b) dissociating the embryo of step a) into cells;
• c) seeding the dissociated cells of step b) in basal medium comprising insulin like growth factor 1 (IGF-1), ciliary neurotrophic factor (CNTF), animal serum, and a layer of feeder cells;
• d) culturing the cells of step c) for at least one passage;
• e) withdrawing the IGF-1 and CNTF from the culture of step d);
• f) culturing the cells of step e) for at least one passage;
• g) progressively withdrawing the feeder cells from the culture of step f);
• h) culturing the cells of step g) for at least one passage;
• i) progressively withdrawing the animal serum from the culture medium of step h) over several passages;
• and
• j) adapting the cells of step i) to suspension culture conditions such that a duck cell line capable of proliferating in basal medium in the absence of exogenous growth factors, a feeder layer, and animal serum is obtained, wherein the duck cell line does not produce replication-competent endogenous retrovirus particles;
• said process of production of virus comprising the steps of:
• 1) proliferating said cells in suspension, in a serum-free medium;
• 2) infecting the cells with said virus;
• 3) culturing said infected cells in order to allow virus replication;
• and
• 4) harvesting said virus.