Effects of peptides derived from traditional Greek yoghurt on expression of pro- and anti-inflammatory genes by ovine monocytes and neutrophils

The objective of the present study was to examine the effect of yoghurt peptides on expression of various pro- and anti-inflammatory genes by ovine monocytes and neutrophils. A total of eight commercial traditional-type Greek yoghurts made with ovine or bovine milk were used. Water-soluble extracts (WSEs) were obtained from all samples. Peptides present in WSE induced cyclooxygenase-2 gene expression and down-regulated inducible NO synthase, Interleukin-1 Receptor Antagonist and Ιnterleukin-12β gene expression in both cell types. Treatment of neutrophils with WSE resulted in a decrease in Interleukin-1β gene expression relative to control. There was a different response from monocytes and neutrophils regarding Transforming Growth Factor-β1 gene expression with an increase by monocytes and a decrease by neutrophils relative to control. Expression of Ιnterferon-γ and Ιnterleukin-10 remained unaffected. In conclusion, peptides derived from Greek yoghurt exhibited a mixed effect (pro- and anti-inflammatory) on two immunocompetent cell populations, although the anti-inflammatory effect was more pronounced.