The present invention is concerned with the specific and highly sensitive detection of specific CHO-MIF complexes in the production of anti-MIF antibodies. The present invention is further concerned with the provision of specific antibodies which can be used for a CHO-MIF detection method.

The present invention is also concerned with a CHO MIF knock-out cell line and use thereof. The present invention also provides preparations obtained from recombinant production in CHO cell lines which are essentially free of CHO-MIF.

The present invention provides novel artificial nucleic acid molecules encoding at least one antigenic peptide or protein and at least one additional sequence preferably targeting the antigenic peptides or proteins to cellular compartments of interest. Further, the invention provides (pharmaceutical) compositions or vaccines and kits comprising said nucleic acid molecules. The nucleic acid molecules, (pharmaceutical) compositions or vaccines and kits are useful for treating a variety of diseases such as cancer, infectious diseases, autoimmune diseases, allergies or graft-versus host disease.