Proliferative effects of synthetic peptides from β-lactoglobulin and α-lactalbumin on murine splenocytes

Eleven peptides, selected on the basis of physicochemical characteristics and their theoretical release from β-lactoglobulin (β-Lg) and α-lactalbumin (α-La) by trypsin or chymotrypsin, were chemically synthesised to evaluate their immunomodulating properties. Murine splenocyte proliferation in the absence and presence of mitogen and different peptide concentrations were measured after 72-96 h incubations. β-Lg f78-83 had no effect on proliferation; β-Lg f15-20, f55-60, f84-91, f92-105, f139-148, f142-148 and α-La f10-16 stimulated proliferation to different extents; β-Lg f1-8, f102-105 and α-La f104-108 showed a cytotoxic effect. Regression analysis revealed the relationship of positive charge, hydrophobicity and length to the stimulatory proliferative effect. β-Lg f15-20, f55-60 and f139-148 also induced various inhibiting and/or stimulating effects on cytokine secretion. The results confirm that peptides releasable by digestive enzymes from α-La and β-Lg have the potential to influence the specific immune response through the modulation of splenocyte proliferation and cytokine secretion.