Immunomodulatory effect of protease hydrolysates from ovotransferrin
Proteins and bioactive peptides in avian egg white exert diverse biological activities. This study is designed to investigate the effect of protease hydrolysates from ovotransferrin (OVT) on bone marrow-derived dendritic cells (BMDCs) maturation. The results show that OVT-derived pepsin hydrolysate effectively inhibits lipopolysaccharide (LPS)-induced BMDCs maturation by reducing the expression levels of MHC-II, CD83, CD86 and the production of TNF-α, IL-12p70, and RANTES, but increases the production of IL-10. In addition, OVT-derived pepsin hydrolysate impairs the ability of LPS-stimulated BMDCs to induce allogeneic T lymphocyte proliferation and decreases the production of IFN-γ by activated T cells. In contrast, OVT-derived trypsin hydrolysate induces DCs maturation in terms of increasing the expression levels of MHC-II and the costimulatory molecules CD83 and CD86 and the production of TNF-α, IL-12p70 and RANTES. Furthermore, OVT-derived trypsin hydrolysate improves the ability of LPS-stimulated DCs to induce allogeneic T lymphocyte activation. Blockage of LPS-induced p38 MAPK and JNK activation and inducing ERK activation contribute to the inhibitory effect of OVT-derived pepsin hydrolysate on DCs, whereas OVT-derived trypsin hydrolysate induces DCs maturation through JNK and ERK activation. These results indicate that OVT-derived protease hydrolysate have an immunomodulatory function and could be applied as a potential functional food ingredient to regulate body immunity by modulating DC maturation.