Fuente: WIPO "biotechnology" The application provides a method of isolating a eukaryotic cell expressing an antibody o f desired specificity, preferably a monoclonal single chain antibody (scFv). The application further provides methods which allow to clone the variable regions of said antibody fro m that isolated eukaryotic cell and to recombinantly produce antibodies comprising said variable regions as fusion protein with a purification tag, eg. as Fc-fusion, as a Fab fragment, or as whole antibodies, such as IgG, IgE, IgD, IgA and IgM. Said methods also allows to recombinantly produce antibodies with desired specificity in a fully species specific form, preferably as fully human antibodies.