تخليص آلرژنهاي عمده شير گاو

Purification of Major Allergen Cow Milk

Food allergy is responsible for most frequent allergic reactions in children under one year of age. Diagnostic tests such as skin test or specific IgE assay commonly need highly purified preparations of allergenic proteins. The aim of the present work was to purify three main proteins; casein, alpha-lactalbumin and beta-lactoglohulin allergenic extracts. First, casein was isolated by isoelectric precipitation of skimmed fresh milk serum or whey. Purification of alpha-lactalbumin was based on fractionation of whey proteins by ammonium sulphate and gel filtration on a Sephadex G-50 column. Beta-lactoglobulin was purified by polyethylene glycol fractionation of whey proteins and ion exchange chromatography on a DEAE-Sepharose column. The isolated proteins were analyzed by polyacrylamide gel from fresh skimmed milk by hydrochloric acid were more soluble in weak alkaline water and purer than the other preparations. Purity of extracts in SDS-PAGE was estimated 95 percent. SDS-PAGE result of isolated alpha-lactalbumin and beta-lactoglobulin and reaction of these products with specific antibodies produced in immunized rabbits showed that they are highly pure. Electrophoretic pattern of purified alpha-lactalbumin or beta-lactoglohulin were composed of a single band, in 14 or 18 KD respectively . In the present investigation three major milk proteins were highly purified. These products can be used in specific tests, i.e. skin test or ELISA.