Bioactivity of beta-lactoglobulin and alpha-lactalbumin-Technological implications for processing

This is the author’s version of a work that was accepted for publication in International Dairy Journal. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in International Dairy Journal, 16(11), November 2006, pp1229–1240.peer-reviewedThe dairy industry faces new technological challenges in order to exploit and maintain some of the bioactive properties of dairy components throughout processing. This review outlines these issues with respect to the two major whey proteins β-lactoglobulin (β-lg) and α-lactalbumin (α-la). Biological activities of both the intact proteins, and peptides derived from the proteins, are discussed e.g. inhibition of angiotensin-converting enzyme (ACE), anti-microbial activity, anti-carcinogenic activity, hypocholesterolemic effect, metabolic and physiological effects. The levels necessary to provide beneficial effects and, if available, evidence from clinical trials are reported. Developments in the purification and enrichment of the proteins are discussed, and the technological implications of industrial processing on the bio-activity of the proteins are examined. The supplementation of infant formulas with α-lactalbumin enriched whey proteins is also discussed in light of its potentially improved bioactive properties

Aberrant IgG galactosylation precedes disease onset, correlates with disease activity, and is prevalent in autoantibodies in rheumatoid arthritis

Objective. To examine the association between aberrant IgG galactosylation and disease parameters in rheumatoid arthritis (RA). Methods. Analysis of N-glycan in serum samples from multiple cohorts was performed. The IgG N-glycan content and the timing of N-glycan aberrancy relative to disease onset were compared in healthy subjects and in patients with RA. Correlations between aberrant galactosylation and disease activity were assessed in the RA cohorts. The impact of disease activity, sex, age, anticyclic citrullinated peptide (anti-CCP) antibody titer, disease duration, and C-reactive protein level on aberrant galactosylation was determined using multivariate analysis. The N-glycan content was also compared between epitope affinity-purified autoantibodies and the remaining IgG repertoire in RA patients. Results. Our results confirm the aberrant galactosylation of IgG in RA patients as compared with healthy controls (mean ± SD 1.36 ± 0.43 versus 1.01 ± 0.23; P \u3c 0.0001). We observed a significant correlation between levels of aberrant IgG galactosylation and disease activity (Spearman\u27s ρ = 0.37, P \u3c 0.0001). This correlation was higher in women (Spearman\u27s ρ = 0.60, P \u3c 0.0001) than in men (Spearman\u27s ρ = 0.16, P = 0.10). Further, aberrant IgG galactosylation substantially predated the onset of arthritis and the diagnosis of RA (3.5 years) and resided selectively in the anticitrullinated antigen fraction. Conclusion. Our findings identify aberrant IgG galactosylation as a dysregulated component of the humoral immune response in RA that begins prior to disease onset, associates with disease activity in a sex-specific manner, and resides preferentially in auto-antibodies. © 2010, American College of Rheumatology