Large-Scale Purification Of Egg Immunoglobulin

The present invention is directed to improved methods for the isolation and purification of egg yolk immunoglobulin or derivatives thereof from eggs produced by immunized or non-immunized arian animals, reptiles, amphibians or fish. The present method is particularly useful for purifying egg yolk immunoglobulins (mainly IgY, IgA and IgM) from a large volume of immune or non-immune egg yolk. The purified products can be used for pharmaceutical purposes, e.g. passive immunization, or as a health food ingredient.

The present invention is also directed toward a method for recovering biologically active components including, for example, ovotransferrin, .delta.-livetin, vitamin-binding proteins, apovitellenins I-VI, .alpha.-lipovitellin, .beta.-lipovitellin, phosvitin, pigments, natural antioxidants, lecithin, enzymes, choline esterase, acid phosphatase, lysozyme, acid protease, anti-inflammatory factor, growth factor, interleukin 1 (IL- 1), IL-2, IL-3, interferons, glucosamine, hexoses, oligosaccharides, phospholipids and sialic acids from egg yolk including the steps of extraction.

The present invention is a method for the purification of egg immunoglobulin including the steps of extraction with e.g. medium-chain fatty acids, and further purification with e.g. ultrafiltration and/or ion exchange chromatography and/or protein precipitation and/or gel filtration and/or desalting and/or drying.

The present invention is directed toward a method for purification of immunoglobulin egg yolk, including the steps of extracting the egg yolk immunoglobulin using medium-chain fatty acids including, for example, caprylic acid, to obtain an immunoglobulin-containing aqueous phase, followed by the steps of subjecting the aqueous phase to ion-exchange chromatography, for example, anion exchange chromatography; subjecting the recovered immunoglobulin fraction to additional ion-exchange chromatography, for example, cation exchange chromatography; subjecting the recovered immunoglobulin to protein precipitation, e.g., ammonium sulfate precipitation; and subjecting the recovered immunoglobulin to gel filtration and/or de-salting by dialysis or diafiltration.

The present invention is further directed toward a method of purification including the steps of extraction with medium-chain fatty acids and ultrafiltration of the resultant aqueous phase before processing as above.

The invention provides processes for obtaining substantial amounts of immunoglobulins in usable form from large volumes of egg yolk, in simple steps, to provide a product of high purity and high yield. The two major products are IgY protein obtained as a retentate from ultrafiltration of the aqueous phase and the pure IgY obtained as summarized above. Major segregation of the immunoglobulin product from egg yolk materials, including lipid, lipoprotein and other proteins is achieved by extraction with 0.5-2.0% medium-chain fatty acids.