The Recognition Pattern of Sequential B Cell Epitopes of Beta–Lactoglobulin Does Not Vary with the Clinical Manifestations of Cow’s Milk Allergy

Abstract

Background: β–Lactoglobulin (BLG) represents one of the major allergens causing cow’s milk allergy (CMA) – a disease with a wide spectrum of clinical symptoms. The aim of this study was to evaluate sequential B cell epitopes of BLG by the Pin–ELISA method. Furthermore, we wanted to investigate a possible association of the IgE recognition patterns in sera of patients with BLG sensitization and the type of clinical reactions following contact with cow’s milk. Methods: Overlapping sequential decapeptides corresponding to the amino acid sequence of BLG were used in Pin–ELISAs specific for human IgE. Tested sera were from 14 individuals with CMA, 8 of them with a history of immediate systemic reactions and 6 with delayed skin reactions following contact with cow’s milk. All of them showed specific IgE antibodies to BLG in the CAP–RAST. Control sera were from 5 healthy nonallergic individuals. Results: All sera from BLG–sensitized individuals showed IgE binding with one region of BLG corresponding to amino acids 95–113. Furthermore, individual sera showed reactions with two further regions, 12–27 and 124–135. Inhibition of IgE binding to BLG with one soluble synthetic peptide confirmed the major epitope. No differences were found in the B cell epitope recognition pattern to BLG in the two groups of patients with CMA, characterized by acute systemic or delayed skin reactions. Conclusions: Using IgE Pin–ELISAs we were able to confirm previously described sequential B cell epitopes of BLG. However, the recognition pattern of one of the major cow’s milk allergens is not predictive of the clinical type of reaction.

IgE and IgG Binding Epitopes on α-Lactalbumin and β-Lactoglobulin in Cow’s Milk Allergy

“…The hydrophilicity profile of the protein suggests that the antigenic site is at AA 124–134, which is on the surface of the protein and described as a major allergenic site in our study and those of other investigators [7, 9, 13]. AA 97–108 was described by Ball et al [10]as a major linear epitope, which corresponded to a major epitope (AA 95–113) also reported by Heinzmann et al [14], but not confirmed in our study or that of Williams et al [13]. Selo et al [12]reported the tryptic fragments AA 1–8, 25–40, 41–60, 102–124 and 149–162 as major IgE binding epitopes in a population of milk-allergic patients whose ages were not reported.…”

“…Previous studies that utilized digested peptide fragments or synthetic peptides have reported different findings with respect to the major sequential IgE binding regions on ALA [7, 8]and BLG [7, 9, 10, 11, 12, 13, 14]. In this study, we mapped sequential (linear) epitopes recognized by IgE and IgG antibodies using synthetic, overlapping decapeptides immobilized on a derivatized cellulose membrane and sera from patients with persistent CMA and those who are likely to outgrow their allergy.…”

Allergenicity of acidic peptides from bovine β-lactoglobulin is reduced by hydrolysis with Bifidobacterium lactis NCC362 enzymes

“…Consistent with this finding, we observed that the IgE binding capacity of tryptic-chymotryptic peptides of BLG was lower than for intact BLG. Although the major allergenic sites are located on the surface of the tridimensional structure of BLG, numerous highly reactive linear epitopes have been described (Ja¨rvinen, Chatchatee, Bardina, Beyer, & Sampson, 2001;Selo et al, 1998;Selo et al, 1999;Heinzmann, Blattmann, Spuergin, Forster, & Deichmann, 1999). These epitopes may become the target of intestinal microbiota, which has been shown to contribute to antigen degradation (Pessi et al, 1998).…”

Reduced β-lactoglobulin IgE binding upon in vitro digestion as a result of the interaction of the protein with casein glycomacropeptide

“…The results are shown in Tables 1 and 2, where the peptide sequences obtained from the digestions were compared to b-lg fragments identified as epitopes by Sélo et al (1999) with different levels of immunoreactivity. Other studies have reported b-lg epitopes (Adams et al, 1991;Heinzmann, Blattmann, Spuergin, Forster, & Deichmann, 1999;Järvinen et al, 2001); however most of them are included in the epitopes described by Seló et al (1999). The number of identified peptides with previously described epitopes was lower for both CMP:b-lg 50:50 (14 and 16 at pH 7.0 and pH 3.5, respectively) compared to 28 and 32 in the b-lg digests.…”