CONTEXT

The production of recombinant proteins and in particular of monoclonal antibodies represents an important market and is in full expansion. It should exceed 30 billions dollars in 2010. These recombinant proteins are finding use as therapeutic agents for the treatment of pathologic disorders, particularly in cancerology and in infectious diseases. Until now, different improved methods using genetic engineering techniques (carried out on bacteria cells, eukaryotic cells and transgenic plants) for the production of proteins have generated great performances in obtaining of large amounts of a desired protein. However, in each system, there still exist some limitations for the production and the purification of complex proteins. Thus, a need exists for methods to conveniently produce and purify proteins in large amounts with low cost. In the present invention, recombinant proteins can be expressed from nuclear genome of green algae, particularly in Ostreococcus sp.