Department of Transplant and Infection Immunology, Saarland University, Homburg, Germany.
AIDS. 2012 Mar 27;26(6):695-700. doi: 10.1097/QAD.0b013e3283519a89.
To assess the effect of antigen-exposure on the T-cell repertoire in the chronic phase of HIV-infection.
This is a prospective cross-sectional study.
HIV-seropositive patients and immunocompetent controls from tuberculosis low and high-endemic countries were recruited. Mycobacterium tuberculosis (purified protein derivative; PPD)-specific CD4 T-cell responses were quantified directly from whole blood using flow-cytometric analysis of intracellular cytokines after specific stimulation. T-cell reactivity toward cytomegalovirus (CMV) or Staphylococcus aureus Enterotoxin B (SEB) served as control.
In a low-endemic region, HIV-seropositive patients showed lower frequencies of PPD-specific T cells compared to immunocompetent individuals. This was not due to a general loss of immunity toward recall antigens, as T-cell immunity toward CMV or SEB was preserved. In line with continuous antigen exposure, HIV-seropositive patients from a high-endemic region showed preserved PPD-specific T-cell frequencies that were not different from those found in HIV-seronegative controls. Likewise, both groups did not differ in recall T-cell responses toward CMV or SEB.
A lower prevalence and frequency of PPD-specific immunity is a typical feature of HIV-related immunosuppression in low-endemic regions. In contrast, PPD-specific responses are maintained in HIV-seropositive individuals in regions with high tuberculosis prevalence. This suggests constant skewing and restriction of specific T-cell immunity toward environmental antigens in HIV-seropositive individuals.
评估 HIV 感染慢性期抗原暴露对 T 细胞 repertoire 的影响。
这是一项前瞻性的横断面研究。
从低、高结核流行国家招募 HIV 血清阳性患者和免疫功能正常的对照者。使用流式细胞术分析细胞内细胞因子，直接从全血中定量检测结核分枝杆菌（纯化蛋白衍生物；PPD）特异性 CD4 T 细胞反应。巨细胞病毒（CMV）或金黄色葡萄球菌肠毒素 B（SEB）的 T 细胞反应作为对照。
在低流行地区，与免疫功能正常者相比，HIV 血清阳性患者的 PPD 特异性 T 细胞频率较低。这不是由于对回忆抗原的一般免疫丧失，因为 CMV 或 SEB 的 T 细胞免疫仍然存在。与持续的抗原暴露一致，来自高流行地区的 HIV 血清阳性患者表现出保留的 PPD 特异性 T 细胞频率，与 HIV 血清阴性对照者无差异。同样，两组对 CMV 或 SEB 的回忆性 T 细胞反应也没有差异。
在低流行地区，PPD 特异性免疫的低患病率和频率是 HIV 相关免疫抑制的典型特征。相比之下，在结核高流行地区，PPD 特异性反应在 HIV 血清阳性者中得以维持。这表明 HIV 血清阳性个体对环境抗原的特异性 T 细胞免疫持续偏倚和受限。
