Proteomic characterization of IgY preparations purified with a water dilution method

Antigen-specific chicken IgY antibodies have been used for oral immunotherapy as an alternative or complement to antibiotics in several studies. The water dilution (WD) method has several advantages for purifying IgY. It is rapid, efficient, suitable for large-scale production, and nothing but water is added. The water-soluble fraction contains other proteins and lipids besides IgY. The protein content was characterized by two-dimensional gel electrophoresis (2DGE) and nanoflow liquid chromatography coupled offline to matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry (nanoLC-MALDI TOF/TOF MS). Protein analysis was complicated due to the large dynamic concentration range, but 26 proteins could be identified. The relative protein concentrations in different batches were very similar according to protein patterns on 1D gels and protein concentration determinations. Thus, the purification method has a high reproducibility. The concentrations of cholesterols and triglycerides were low and should not have an effect on the plasma levels of treated patients. Purification of IgY for oral use with WD is therefore a recommended method.