Effect Of Two Peptides On Mononuclear

Objective:Thymosin is a family of polypeptides hormone produced by thymic epithelial cells,which play an important role in the differentiation, maturation, and function of lymphocytes.Peripheral blood mononuclear cells(PBMCs) include lymphocytes and monocytes.Macrophages participate in both the innate and aquired arms of the immune response. they are,in effect,a bridge between the two arms.The cell-mediated arm consists primarily of T lymphocyte, which can be divided into several subsets, each has its specific surface marker and function.According to the expression of CD molecules,T lymphocyte can be divided into CD4+ Tcells and CD8+Tcells.According to its functional, it can be divided into helper T cell(Th),regulatory T cell(Treg),cytotoxic T cell(CTL)et al. The changes of costimulatory molecules on the surface of macrophages and T lymphocyte subsets proportion, kinds of cytokine may reflect the immune function of the state.Therefore, this study examined human,s PBMCs and THP1 cells as the research object to investigate the effects of two peptides on immune cells activity.Methods:1PBMCs of healthy subjects were treated with various concentrations of three peptides( α1and α2 and tymosin) for 48 h and 72 h,T lymphocyte subsets(such as CD4+ T cells and CD8+T cells) were detected by flow cytometry(FCM).2PBMCs of healthy subjects were treated with various concentrations of three peptides( α1and α2 and tymosin) for 48 h and 72 h, multiplex cytokines(such as IL-2,IL-6,IL-10,TNF-α and IL-1β) were detected by Cytometric Beads Array(CBA).3After treated with various concentrations of three peptides( α1and α2 and tymosin)for 24 h and 48 h, TNF-α and IL-1β in THP-1 monocyte-derived macrophages were detected by Cytometric Beads Array(CBA), Flow cytometry was used to determine the surface expression of HLAII and co-stimulatory molecular CD86.Effect of three peptides( α1and α2 and tymosin) on THP-1 cells proliferation was analyzed by means of CCK8 method.We use neutral red method to detect the effects of three peptides( α1and α2 and tymosin) on THP-1 phagocytic function.Results:1 Effects of two peptides on human peripheral blood mononuclear cells1.1 CBA indicated1.1.1 Compared to negative control,PBMCs were stimulated with two peptides( α1 and α2)at various concentrations for 48 h,and there was significant increases in the secretion of IL-6,IL-10,TNF-α and IL-1β.Especially 10mg/ml α1 peptide increased the secretion of IL-6,IL-10,TNF-α and IL-1β significantly(P<0.05). Compared to positive control,two peptides( α1 and α2)showed no significant changes among various concentrations but α1 peptide(10mg/ml)(P>0.05).1.1.2 Compared to negative and positive controls, two peptides( α1 and α2) treatment for 72 h caused no significant changes in the secretion of IL-6,TNF-α and IL-1β(P>0.05).Compared with control groups, No significant differences were observed in the IL-2 produced by PBMCs treatment with two peptides( α1 and α2) for 48 h and 72h(P>0.05).1.2 Compared to negative and positive controls,there was no significant change in the percentage of CD4+ and CD8+T cells in PBMCs treated with two peptides(α1 and α2)( P>0.05).2Effects of two peptides on THP-1 cells2.1 Compared with negative control,after 24 h of stimulation, α2 peptide at the concentrations of 5mg/ml and 10mg/ml increased the expression of HLAII molecules on THP-1cells(P<0.05).But other concentrations of two peptides can not increase the expression of HLAII molecules.Compared with negative and positive groups, treatment with two peptides( α1 and α2)at various concentrations resulted in no significant changes of CD86 expression on THP-1cells( P>0.05).2.2 Compared to negative and positive controls, two peptides( α1 and α2) can not significantly promote THP-1 cell proliferation and phagocytosis.2.3 The TNF-α and IL-1β secretion levels were undetected in THP-1 under the various treatment conditions.Conclusions:1Two peptides elevates the levels of inflammatory cytokines and inhibitory cytokines in PBMCs.2Two peptides have no effect on T cell subsets and therefore have no effect on T lymphocyte activation.3α2 peptide can increase the expreesion of HLAII molecule in THP-1, which suggest α2 peptide can increase antigen presenting ability of macrophage.