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Relative allergenicity of modified bovine milk proteins

University of British Columbia

Cow's milk contains a variety of proteins which are capable of eliciting an allergic reaction. The casein fraction and S-lactoglobulin of the whey fraction are recognized as the most potent allergens in cow's milk. It is not known, however, whether the individual sub-fractions of casein possess equal allergenicity. In this study, the relative allergenicities of ce81 and S casein were determined. The relative allergenicities of both caseins after enzymic dephosphorylation were also investigated. In addition, the relative allergenicity of whey after the partial removal of S-lactoglobulin by FeCl3 precipitation was studied. The relative allergenicity of the milk proteins was determined by the passive cutaneousa naphylaxis (PCA) assay, which utilized antisera obtained from mice that were exposed to the test proteins using separate oral and intraperitoneal experimental protocols. In addition, an enzyme linked immunosorbent assay (ELISA) was used to determine the relative concentrations of antigen specific immunoglobulins G and E in the antisera. Mice which received the test proteins by oral administration were not sensitized against the proteins. In contrast, results obtained from mice exposed to the test proteins by intraperitoneal injection, revealed thatd ephosphorylated ces, casein and S casein were allergenic while native a81 casein was not. The dephosphorylation of S-casein did not significantly affect allergenicity. The partial removal of g-lactoglobulin did not significantly reduce the allergenicity of whey. The proteins which remain in the whey after treatment with FeCl3 (primarily u-lactalbumin and a residual amount of 0-lactoglobulin) are equal to untreated whey in their ability to produce an allergic reaction.

Thesis/Dissertation

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2008-10-10

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http://hdl.handle.net/2429/2533

Food Science

University of British Columbia

UBCV

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