Shmagel Konstantin, Saidakova Evgeniya, Korolevskaya Larisa, Vlasova Violetta, Younes Souheil-Antoine
Institute of Ecology and Genetics of Microorganisms UB RAS, Perm Federal Research Center UB RAS, 614081 Perm, Russian Federation.
Biological Faculty, Perm State University, 614000 Perm, Russian Federation.
Front Biosci (Landmark Ed). 2024 Dec 25;29(12):429. doi: 10.31083/j.fbl2912429.
Regulatory T-cells (Tregs) play a crucial role in maintaining immune homeostasis, but their dynamics are altered in a subset of people living with Human Immunodeficiency Virus (HIV) known as immunological non-responders (INRs). INRs fail to reconstitute CD4 T-cell counts despite viral suppression. This study aimed to examine Treg dysregulation in INRs, comparing them to immunological responders (IRs) and healthy controls (HCs).
The study included 40 INRs, 42 IRs, and 23 HCs. Peripheral blood mononuclear cells were isolated and analyzed by flow cytometry. Conventional CD4 T-cells (Tconvs) were identified as CD25FOXP3 cells, while Tregs were identified as CD25CD127FOXP3 CD4 T-cells. Cells were further divided into naive, central memory, effector memory, and effector memory cells re-expressing CD45RA (TEMRA) subsets. Activated/cycling cells were identified as CD71 and quiescent cells were CD71. Mitochondrial mass and transmembrane potential were measured using MitoTracker Green and MitoTracker Orange dyes, respectively. Statistical comparisons were made using the Kruskal-Wallis test with Dunn's post-hoc analysis and Mann-Whitney U-test.
INRs exhibited the highest frequencies of activated/cycling CD4 T-cells. The proportion of activated/cycling cells was higher in Tregs compared to Tconvs in all groups. Cycling rates of Tregs and Tconvs were correlated, suggesting Tregs help control Tconv proliferation. Despite high overall Treg frequencies in INRs, they showed a Treg deficiency in activated/cycling CD4 T-cells, specifically in naive and central memory subsets, causing an imbalance in the Tconv/Treg ratio. This deficiency was hidden by increased Treg frequencies in quiescent effector memory CD4 T-cells. Activated/cycling naive and memory Tregs from INRs had normal forkhead box P3 (FOXP3) and CD25 expression, but activated/cycling memory Tregs showed decreased ability to regulate mitochondrial transmembrane potential, indicating impaired mitochondrial fitness. These mitochondrial abnormalities were similar to those observed in memory conventional T-cells.
The complex Treg dysregulation in immunological non-responders involves quantitative and functional alterations, including a Treg deficiency within activated/cycling naive and central memory CD4 T-cells, impaired mitochondrial fitness of activated/cycling memory Tregs, and functional disorders of the parent conventional T-lymphocytes. These findings underscore the need for a nuanced understanding of Treg dynamics in suboptimal CD4 T-cell reconstitution during HIV-infection.
调节性T细胞（Tregs）在维持免疫稳态中起关键作用，但在一部分感染人类免疫缺陷病毒（HIV）的免疫无应答者（INRs）中其动态变化发生改变。尽管病毒得到抑制，但INRs的CD4 T细胞计数未能恢复。本研究旨在检查INRs中的Treg失调情况，并将其与免疫应答者（IRs）和健康对照者（HCs）进行比较。
该研究纳入了40名INRs、42名IRs和23名HCs。分离外周血单个核细胞并通过流式细胞术进行分析。传统CD4 T细胞（Tconvs）被鉴定为CD25FOXP3细胞，而Tregs被鉴定为CD25CD127FOXP3 CD4 T细胞。细胞进一步分为初始、中枢记忆、效应记忆和重新表达CD45RA的效应记忆细胞（TEMRA）亚群。活化/增殖细胞被鉴定为CD71，静止细胞为CD71。分别使用MitoTracker Green和MitoTracker Orange染料测量线粒体质量和跨膜电位。采用Kruskal-Wallis检验及Dunn事后分析和Mann-Whitney U检验进行统计学比较。
INRs表现出活化/增殖CD4 T细胞的频率最高。在所有组中，Tregs中活化/增殖细胞的比例高于Tconvs。Tregs和Tconvs的增殖率相关，表明Tregs有助于控制Tconv增殖。尽管INRs中Treg的总体频率较高，但它们在活化/增殖CD4 T细胞中，特别是在初始和中枢记忆亚群中表现出Treg缺陷，导致Tconv/Treg比例失衡。这种缺陷被静止效应记忆CD4 T细胞中Treg频率的增加所掩盖。来自INRs的活化/增殖初始和记忆Tregs具有正常的叉头框P3（FOXP3）和CD25表达，但活化/增殖记忆Tregs调节线粒体跨膜电位的能力下降，表明线粒体适应性受损。这些线粒体异常与在记忆传统T细胞中观察到的异常相似。
免疫无应答者中复杂的Treg失调涉及数量和功能改变，包括活化/增殖初始和中枢记忆CD4 T细胞内的Treg缺陷、活化/增殖记忆Tregs的线粒体适应性受损以及母代传统T淋巴细胞的功能障碍。这些发现强调了在HIV感染期间对CD4 T细胞重建不佳时Treg动态变化进行细致入微理解的必要性。
