title: Identification of the human beta-casein C-terminal fragments that specifically bind to purified antibodies to bovine beta-lactoglobulin.
abstract: The presence of foreign proteins in human milk after the ingestion of bovine dairy products is thought to be one of the possible causes of allergic sensitization in exclusively breast-fed predisposed infants. The immunologic determination of bovine beta-lactoglobulin (LG) concentration in human milk has been reported by several researchers, but the results are conflicting. Moreover, a strong cross-reactivity between antibodies to bovine beta-LG and human milk proteins and peptides was reported, throwing doubt on the reliability of radioimmunoassay and enzyme-linked immunosorbent assay detection and quantification assays for bovine beta-LG in human milk. Thus, the goal of this study was to isolate human milk peptides with a molecular mass >or= 1,000 Da cross-reactive with antibodies to bovine beta-LG in order to identify possible common epitopes between human and bovine milk proteins. The proteins were first isolated by affinity chromatography with purified polyclonal antibodies to bovine beta-LG, followed by gel filtration fast phase liquid chromatography and reverse phase-high performance liquid chromatography purification of the components specifically bound in the affinity separation step. Affinity-bound peptides were identified by determining their amino acid sequence. All the sequenced peptides belonged to the C-terminal part of human beta-casein, which confirms the cross-reactivity of human milk proteins and peptides with antibodies to bovine beta-LG and allows the identification of possible common epitopes between the two proteins. No bovine beta-LG peptides with a molecular mass >or= 1,000 Da were found in our milk samples from healthy mothers on a diet rich in bovine milk and dairy products.
authors.affiliation: Centro Studi Alimentazione Animali, CNR, c/o Bioindustry Park, Colleretto Giacosa (TO), Italy.
authors.forename: A
authors.initials: A
authors.lastname: Conti
authors.forename: M G
authors.initials: MG
authors.lastname: Giuffrida
authors.forename: L
authors.initials: L
authors.lastname: Napolitano
authors.forename: S
authors.initials: S
authors.lastname: Quaranta
authors.forename: E
authors.initials: E
authors.lastname: Bertino
authors.forename: A
authors.initials: A
authors.lastname: Coscia
authors.forename: S
authors.initials: S
authors.lastname: Costa
authors.forename: C
authors.initials: C
authors.lastname: Fabris