Characteristics and immune mechanisms of CD71+ CD235a+ nucleated erythroid cells in elderly

Objective To explore the immune property and possible mechanism of the CD71+ CD235a+ nucleated erythroid cells from peripheral blood in elderly, as compared with those of healthy young. Methods Peripheral blood obtained by venipuncture from healthy young(n=59, mean age=28 years)and elderly(n=78, mean age=68 years)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 older 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 0.05). (3)The results of Real-time PCR revealed that, compared with CD71+ CD235a+ cells from the young, CD71+ CD235a+ cells from the elderly expressed 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, all 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. Key words: Suppressor factors, immunologic; Lymphocytes; Erythrocytes