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Carbohydrate epitopes on the arabinogalactan protein (AGP) gum arabic recognised by a panel of seven monoclonal antibodies (MAbs), raised in a previous study, have been further characterised. These MAbs have now been divided into three groups based on their response to mild hydrolysis and elimination (neutral hydrolysis) when heated in buffers at different pH values. We have also investigated the binding of these antibodies to three fractions of gum arabic separated by hydrophobic interaction chromatography. MAb groups I and III produce consistent responses when tested against heat-treated whole and fractionated gum arabic, whilst group II display a varied response suggesting that these MAbs recognise complex epitopes, the structure of which is not immediately apparent. It appears that neutral hydrolysis is capable of increasing or decreasing the affinity of certain epitopes, whilst hydrolysis with a strong acid (TFA; tri-fluoro acetic acid) under harsh conditions reduces the affinity for all antigens. The results obtained have shown that the MAbs can be divided into three categories, two of which have distinctive and easily reproducible responses to treatment of the gum and would therefore be suitable for the investigation of Acacia gums which have been subjected to food preparation procedures. [ABSTRACT FROM AUTHOR]

Soybean meal in the post-weaning diet of pigs results in a growth lag correlated with Immunoglobulin G (IgG) production against soybean proteins, including the seed storage protein β-conglycinin. We screened sera from 30 pigs for IgG directed against β-conglycinin. Analysis of the same sera on protein blots identified sera that had IgG against the α-subunit of β-conglycinin. A tiled peptide array (16 amino acids with an 11 amino acid overlap) of the α-subunit of β-conglycinin was screened to identify the epitopes of the α-subunit that bind IgG. One major IgG binding epitope previously identified was confirmed. A second major IgG binding epitope was identified that bound IgG from half of the animals tested. Minor epitopes that bound IgG from one or two other sera were also identified. Binding of IgG to β-conglycinin in an enzyme-linked immunosorbent assay (ELISA) was inhibited by a synthetic peptide representing one of the minor epitopes. [ABSTRACT FROM PUBLISHER]

ELISA is a cheap, fast and simple method for the detection of food allergens. Use of chicken antibodies in the analysis of food allergens and specifically the effect of the immunisation frequency on antibody generation is not well documented. This study aimed at comparing the activity of the immunoglobulins generated using a three-week and a six-week immunisation protocol. Isa brown chicken were immunised with 500 µg of roasted peanut protein extract using varying booster injection intervals. After induction, antibody production was sustained during the immunisation period in the six-week protocol with a marked drop in the three-week regime. The activity of antibodies was higher in the six-week protocol than the three-week protocol. An assay was optimised in the detection range of 1 ppm. Upon heating, the peanut protein binding by IgYs decreased with subsequent fluctuations. This was associated with denaturation of proteins and unmasking of new epitopes and stable fractions persisting. [ABSTRACT FROM PUBLISHER]

We conducted enzyme-linked immunosorbent assay (ELISA) and basophil-activation assay in order to investigate the presence of allergens in selected cow milk (CM) substitutes. Our results showed the presence of residual antigenicity and allergenicity. The cross-reactivity between proteins from different animal species was observed. CM allergen-induced histamine release was dose-dependent. Therefore, differences in the relative percentage of major allergens may lead to a discrepancy between allergenic and antigenic activity. The presence of very similar epitopes could explain the cross-reactivity in mammalian milks. [ABSTRACT FROM AUTHOR]

Ten monoclonal antibodies (MAbs) against serogroup B salmonellae were obtained after immunisation of BALB/c mice with outer membrane proteins (OMPs) from Salmonella enterica serovar Typhimurium. Affinity constants, measured by enzyme-linked immunosorbent assay (ELISA), ranged from 8×05 to 6×07 l mol-1. Additivity ELISA demonstrated that most MAbs recognise different epitopes. ELISA determined the antigen specificity of the MAbs. The MAbs were more reactive with live Salmonella Typhimurium than with heat-treated cells. Two MAbs were used to develop a sandwich ELISA for rapid detection of Salmonella Typhimurium in experimentally contaminated meats. Its detection limit was 105 CFU ml-1 and it was able to detect 1-10 CFU in post-enrichment broth from 25 g of beef and chicken meat samples. The sandwich ELISA developed was shown to be specific and sensitive for the detection of Salmonella Typhimurium in meat, and produced results comparable to the culture methods in 57 h. [ABSTRACT FROM AUTHOR]

The kinetics of the denaturation of antigen determinant (AGD) region and protein G-binding (PGB) region of bovine immunoglobulin G (IgG) in acidic colostral whey were studied by single radial Immunodiffusion (SRID) and protein G affinity chromatography (PrGAC) during the same courses of heat treatment. The kinetic and thermodynamic parameters for heat-induced denaturation of AGD and PGB regions of IgG were determined over a temperature range of 69-81°C. The denaturation reactions of both AGD and PGB regions of IgG were best described with apparent reaction order of 1.2, the activation energy values of the denaturation reactions were 159.42 kJ/mol and 235.37 kJ/mol respectively. This work suggested that the AGD region was more heat-labile than the PGB region of IgG in acidic colostral whey, Moreover, the higher values of the constant for the AGD region meant that, once the unfolding of the region started, denaturation would occur more quickly than the PGB region on IgG molecule. All these factors contributed to the fact that generally the IgG contents in the products of bovine colostrum determined by PrGAC would be higher than those by SRID. [ABSTRACT FROM AUTHOR]

Mal d 1, the major apple allergen shows strong cross-reactivity with IgE specific for the major birch pollen allergen, Bet v 1, and is responsible for birch pollen related food allergy to apple. In contrast to other food and pollen allergens, only a few data on the B-cell epitopes of Mal d 1 are available. To obtain data on the antibody binding epitopes of Mal d 1 and to gain insights to the structures responsible for its B-cell cross-reactivity to Bet v 1, the binding characteristics were studied with 3 monoclonal antibodies (MAbs) raised against Mal d 1 and with patients' IgE directed against Mal d 1 and Bet v 1 by immunoblotting and ELISA. The different binding characteristics of these three MAbs indicated that the MAbs 1D6, 2B2 and 3F8 recognized different epitopes on the major apple allergen. MAb 2B2 cross-reacted with Bet v 1 on immunoblots, whereas 1D6 and 3F8 did not. Since 1D6 and 2B2 (but not 3F8) always competed with IgE from the same apple-allergic patients, 1D6 may be a useful tool for Mal d 1 epitope studies and 2B2 for an epitope that cross-reacts with IgE specific for Bet v 1. [ABSTRACT FROM AUTHOR]