The Immunomodulatory Effect Of Protease Hydrolysates From Ovotransferrin

Proteins in food are digested by enzymatic hydrolysis to form polypeptides and free amino acids in gastrointestinal tract.Then,some immunoactive peptides are recognize by antigen presenting cells(APC),and are presented to T cells to initiate immune response.Ovotransferrin(OVT)is the main component in avian egg white.A large number of studies have shown that OVT has immunomodulation activity and improve the body immunity by modulating dendritic cells(DCs)maturation.OVT cannot be directly absorbed in body,and it will go through enzyme hydrolysis into protease hydrolysates.However,the effect of protease hydrolysates from OVT on the regulation of immune response is still unknown.In order to investigate the immunomodulatory effect of protease hydrolysates from OVT,this study focused on investigating the effect of OVT-derived pepsin hydrolysates(PH)and OVT-derived trypsin hydrolysate(TH)on DCs maturation and function.Firstly,murine bone marrow-derived dendritic cells were cultured in vitro and observed the cellular morphology by inverted microscope and examined the expression level of the characteristic surface molecules on DCs by flow cytometry.Secondly,cytokines and chemokines production in DCs supernatant were measured by ELISA and the capacity of matured DCs to allogeneic T cell proliferation was measured by MLRs.Meanwhile,the secretion of IFN-?,IL-4 in mixed cell supernatant was detected by ELISA to study the direction of T cell differentiation.At last the expression of MAPK signal pathway protein-p38 MAPK,JNK and ERK and their phosphorylation protein were measured by western blotting to investigate the involved molecular mechanism.The results summarized as follows:(1)OVT-derived pepsin hydrolysate effectively down-regulated the expression levels of MHC-II,CD83 and CD86 in LPS-induced DCs.OVT-derived trypsin hydrolysate up-regulated the expression levels of MHC-II,CD83 and CD86.The result showed that OVT-derived pepsin hydrolysate could attenuate LPS-induced DCs phenotypic maturation,and OVT-derived trypsin hydrolysate induce DCs phenotypic maturation.(2)OVT-derived pepsin hydrolysate inhibited the production of TNF-?,IL-12p70 and RANTES,but increased the production of IL-10.OVT-derived trypsin hydrolysate induced the production of TNF-?,IL-12p70 and RANTES,but decreased the production of IL-10 in LPS-induced DCs.(3)OVT-derived pepsin hydrolysate impaired the ability of LPS-stimulated DCs to induce allogeneic T lymphocyte proliferation and decreased the production of IFN-? by activated T cells.In contrast,OVT-derived trypsin hydrolysate induced the ability of LPS-stimulated DCs to induce allogeneic T lymphocyte proliferation and increased the production of IFN-?.The results indicated that OVT-derived pepsin hydrolysate inhibited DCs functional maturation,OVT-derived trypsin hydrolysate induced DCs functional maturation.(4)OVT-derived pepsin hydrolysate down-regulated LPS-induced p-p38 MAPK and p-JNK expression and induced p-ERK expression.OVT-derived trypsin hydrolysate up-regulated LPS-induced p-JNK and p-ERK expression.The results suggested that OVT-derived pepsin hydrolysate may block p38 MAPK and JNK signal pathway,and induced ERK to inhibit DCs maturation.OVT-derived trypsin hydrolysate induced JNK and ERK signal pathway to induce DCs maturation.