Schenk, J.A.J.A.SchenkFettke, J.J.FettkeLenz, C.C.LenzAlbers, K.K.AlbersMallwitz, F.F.MallwitzGajovic-Eichelmann, N.N.Gajovic-EichelmannEhrentreich-Förster, E.E.Ehrentreich-FörsterKusch, E.E.KuschSellrie, F.F.Sellrie2022-03-042022-03-042012https://publica.fraunhofer.de/handle/publica/22890510.1016/j.jbiotec.2011.12.025The large scale production of a monoclonal anti-progesterone antibody in serum free medium followed by affinity chromatography on protein G lead to a contamination of the antibody sample with a protein of about 14. kDa. This protein was identified by mass spectrometry as secretory leukocyte protease inhibitor (SLPI). This SLPI contamination lead to a failure of the fiber-optic based competitive fluorescence assay to detect progesterone in milk. Purification of the monoclonal antibody using protein A columns circumvented this problem.en610660journal article