Immunomodulatory activities of whey β-lactoglobulin tryptic-digested fractions

Although bioactive peptides can be obtained from whey protein hydrolysis, data about their immune effects are inconclusive. The in vitro effects on the human immune system of different β-lactoglobulin tryptic-digested fractions separated by membrane filtration were evaluated, analysing the proliferation, cytokine secretion and differentiation of human peripheral blood cells. This procedure allowed the enrichment of peptide sets with specific features, suggesting that the differences in the peptidic composition were related to their immune function. The fraction enriched in large and acid peptides was able to induce Th1 responses, whereas fractions containing short peptides were involved in monocyte activation increasing TNFα secretion. Moreover, one of these fractions was able to induce TGFβ secretion and regulatory T cell differentiation, key mechanisms by which whey-derived peptides could impair allergic and inflammatory responses. No impact on immune cells was triggered by the unfractionated hydrolysate, supporting the use of membrane-fractionating techniques for obtaining immune bioactive-enriched fractions.