Study On Characteristics And Immune Mechanisms Of CD71~+CD235a~+ Nucleated Erythroid Cells In Elderly

Objective: The nucleated erythroid cells possess the ability of negative immunomodulation. The nucleated erythroid cells of the neonatal abundant in the peripheral blood and cord blood have proved to suppress the immune system of the neonatal. However, it is uncertain if there has changes or what’s the changing characteristics of the nucleated erythroid cells of the aged in the peripheral blood during the process of age. To explore the immune property and possible mechanism of the CD71+CD235a+ nucleated erythroid cells from peripheral blood in elderly, we compared with those of the healthy young.Methods:Peripheral blood obtained by venipuncture from healthy young(n=59, mean age=28) and aged(n=78, mean age =68) donors were measured by flow cytometry to evaluate the frequency of the CD71+CD235a+ cells in peripheral blood mononuclear cells(PBMC). In vitro assays, CD71+CD235a+ cells were sorted by flow cytometry and T cells were sorted using CD4+ T cell isolation kit, then the T cell proliferation assays were conducted by following groups: T cell + CFSE group; T cell +CFSE co-cultured with CD71+CD235a+ cells from the young donors; T cell + CFSE co-cultured with CD71+CD235a+cells from the old donors. Real-time PCR were used to identify the expression of the immune cytokine secreted by CD71+CD235a+ cells.Results:(1)the results showed a significant increase in the percentage of CD71+CD235a+ cells in the elderly compared with the young(9.93 ? 2.95% vs 1.96 ? 1.16%, t=3.37 P<0.001);(2)the CD71+CD235a+ cells from the elder donors could suppress the proliferation of the T cells(t=2.91,P<0.05) while from the young group we could not observe this phenomenon(t=0.387,P>0.05);(3) The results of Realtime PCR revealed that, compared with CD71+CD235a+ cells from the young, CD71+CD235a+ cells from the elderly express higher levels of Arg-2( t=9.04, P<0.01), IL-1β, IL-6 and TGF-β(t=4.51, 5.46, 6.92,p<0.05).Conclusions: There are higher frequencies of CD71+CD235a+ cells in aged samples than the young. And the CD71+CD235a+ cells from the elderly could secrete more Arg-2, IL-1β, IL-6 and TGF-β to suppress the T cell proliferation.