中国恒河猴感染SIV后T淋巴细胞初始、记忆亚群的变化

摘要

目的:对中国恒河猴感染猴免疫缺陷病毒(SIV)后CD4 T初始、记忆亚群的细胞进行分析,了解各亚群的变化规律以及在AIDS发病过程中的意义.方法:使用SIVmac239毒株感染20只中国恒河猴,观察18个月;在感染前、后各时间点,使用实时荧光定量PCR(TaqMan探针法)进行病毒载量的检测;使用CD3/CD4/CD28/CD95表面标记的组合,进行CD4及其初始/记忆亚群比例的流式分析,并结合血常规检测的结果计算CD4及其各亚群的绝对数.结果:得到了CD4各个亚群在SIV感染后的变化曲线;并发现SIV感染后CD4减少的主体是中央型记忆(CM)CD4+T细胞;而初始型CD4+T在半数动物逐渐缓慢减少,但个体间差异较大.此外,还发现快速进展型RM449猴在死亡前其初始型及CM CD4仍较高,但其初始型CD4细胞在流式图上存在着类似"转化阻滞"的现象.结论:本研究展示了CD4细胞的初始、记忆亚群在感染SIV后的变化规律;对其进行细分研究,有助于更准确地了解体内免疫状态的变化,为临床疗效观察、免疫状态评估等提供参考.%Objective:To explore the dynamics of T-cell naive/memory subsets in SIV infected Chinese rhesus monkeys. Methods: 20 Chinese rhesus monkeys were infected by SIVmac239, and their plasma viral load were determined by quantitative Taqman real-time RT-PCR analysis within a follow-up period of 18 months. Moreover, proportions of their CD4+ T cells and its naive/memory subsets were analyzed by flow cytometry using a combination of surface markers CD3/CD4/CD28/CD95, by which the absolute cell counts of CD4 and its subsets were also computed based on the routine blood tests. Results: Dynamics of the T-cell naive/memory subsets including their percentages and absolute counts were illustrated. Moreover, central memory CD4 showed to be the majority of cell-loss after SIV infection, which decreased more significantly and accordantly than total CD4, and should be further evaluated as a better indicator for clinical surveillance and drugs judgement. Naive CD4 T cell also decreased gradually with disease progression in half of these animals with more variation among individuals. But impressively, 1 monkey ( RM449 ) with rapidly disease progression died with relatively higher naive and central memory CD4 + T cells, which may be partially explained by the blockage of naive CD4 differentiation into effector memory CD4, as revealed by the flow cytometry assay. Conclusion: The dynamics of different subsets of CD4 T cells in Chinese rhesus monkeys infected with SIVmac239 were surveyed. These data are necessary for the further research of cellular anti-SIV immunity, and may be useful for the clinical judgement of immune reconstitution and vaccine evaluation in HIV/AIDS research.