摘要:
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 < 0.001];(2)the CD71+ CD235a+ cells from the older 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 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.%目的 探讨老年人CD71+ CD235a+有核红细胞的免疫功能特点及可能涉及的机制.方法 分别取健康老年人及青年人外周血,通过流式细胞仪测定各组CD71+ CD235a+有核红细胞占外周血单个核细胞(PBMC)的比例;通过流式分选法分选获得各组有核红细胞,磁珠分选法获得T细胞,T细胞增殖实验分3组进行:老年组:老年有核红细胞+经羟基荧光素=醋酸盐琥珀酰亚胺脂(CFSE)染色的T细胞;青年组:青年人有核红细胞+经CFSE染色的T细胞;对照组:经CFSE染色的T细胞;实时荧光定量PCR法比较青年组及老年组有核红细胞表达免疫抑制性细胞因子的差异.结果 (1)老年人有核红细胞占PBMC比例高于青年人[(9.93±2.95)%和(1.96±1.16)%,t=3.37,P<0.001];(2)老年组有核红细胞能显著抑制T细胞的增殖(t=2.91,P<0.05),而青年组并没有这一现象(t=0.387,P>0.05);(3)与青年组相比,老年组有核红细胞能分泌更多量的精氨酸酶(Arg)-2(t=9.04,P<0.01)、白细胞介素(IL)-1β、IL-6和转化生长因子(TGF)-β(t=4.51、5.46、6.92,均P<0.05). 结论 老年人外周血有核红细胞占外周血单个核细胞比例较青年人高;老年人外周血有核红细胞可能通过释放更多量的Arg-2,IL-1p,IL-6和TGF-p来抑制T细胞的增殖,从而发挥免疫抑制的作用.