66 research outputs found
Quantitative analysis of bovine whey glycoproteins using the overall N-linked whey glycoprofile
Get PDFBovine whey is an important ingredient in human nutrition and contains many biofunctional, glycosylated proteins. Knowledge on the glycoprotein composition of whey and whey products is valuable for the dairy industry. This paper describes a method for the characterisation of whey, or whey powders, by N-linked glycoprofile analysis. Application of the method for analysis of whey protein products showed clear differences in glycoprotein composition between concentrate, isolate and demineralised whey powders. The quantitative potential was explored by screening 100 pooled farm milk samples. IgG and lactoferrin protein concentrations determined by N-glycoprofile analysis matched well with ELISA results. The protein concentration of GlyCAM-1 was determined to be ≥1 mg mL−1. The approaches presented in this work allow simultaneous concentration estimation of the three major whey glycoproteins, lactoferrin, IgG and GlyCAM-1 on the basis of their N-linked glycoprofiles, also in highly processed samples where conventional methods of detection (ELISA) are less suitable
Modulation of Contact Sensitivity Responses by Bacterial Superantigen
Get PDFSuperantigens are potent modulators of the immune system, especially T cells. Therefore, we determined the influence of superantigens on the T-cell-mediated immune response, contact sensitivity. We chose the combination of staphylococcal enterotoxin B (SEB) as superantigen and 2,4-dinitrofluorbenzene (DNFB) as the contact sensitizer, because in BALB/c mice SEB reacts almost exclusively with Vβ8+ T cells, and these cells are capable of transferring contact sensitivity to DNFB from sensitized donors to naive syngeneic recipients. Pretreatment with a single intradermal injection of 50 ng SEB 24 h before DNFB exposure at the same site on the lower abdomen enhanced the induction of contact sensitivity: its intradermal injection permitted sensitization with non-sensitizing concentrations of DNFB as assessed by ear swelling responses after challenge with DNFR. In contrast, pretreatment with repeated intradermal injections of 50 ng SEB every other day over at least 1 week inhibited the induction of contact sensitivity following sensitization. The enhancing effect of SEB may be explained by the creation of a proinflammatory milieu in the skin after a single intradermal injection of the bacterial toxin, whereas the inhibitory effect may be due to tolerization of Vβ8+ T cells. The data indicate that products of skin-colonizing bacteria that can serve as superantigens are able to augment or inhibit the development of contact sensitivity
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