HIV-specific CD4+Th17 cells from HIV infected long-term non-progressors exhibit lower CTLA-4 expression and reduced apoptosis

Progressive HIV infection is marked with reduced frequency and impaired function of Th17 cells. Since T-cell functional responses are regulated by various inhibitory receptors; we examined the expression profile of CTLA-4, PD-1, Tim-3 and apoptotic marker: Caspase-3 on virus-specific Th17 cells from HIV-infected Long-Term Non-Progressors (LTNPs), chronic disease progressors and HIV-uninfected healthy controls (HC) using flowcytometry. Real-time PCR was done to analyze the mRNA expression of Th17 and Treg specific genes. LTNPs showed higher frequencies of HIV-specific Th17 cells; higher mRNA expression of IL-17, IL-22 while lower expression of IL-10; along with lower Caspase-3 expression than the progressors. Among inhibitory receptors, expression of CTLA-4 was 27 and 8 fold; PD-1 was 8 and 6 fold while Tim-3 was 7 and 6 fold higher in progressors and LTNPs respectively than HC. Among HIV-infected patients, LTNPs had 3-fold lower expression of CTLA-4 on HIV-specific Th17 cells than progressors (p?=?0.06). Caspase-3+ve Th17 cells were associated with HIV-specific Th17 cells expressing CTLA-4 (r?=?0.66;p?<?0.0001), PD-1 (r?=?0.40;p?=?0.02) and Tim-3 (r?=?0.35;p?=?0.04). To conclude, virus-specific Th17 cells from LTNP maintained IL-17 production, expressed low levels of CTLA-4 and reduced apoptosis. The study suggests that such functional competence of Th17 cells could be one of the factors in maintenance of non-progressive HIV infection.     

Effector HIV-specific cytotoxic T-lymphocyte activity in long-term nonprogressors: associations with viral replication and progression

Ex vivo effector cytotoxic T-lymphocyte (CTL) activity was assessed in 27 members of the Australian Long-Term Nonprogressor cohort and correlated with genetic, virological, and immunological markers. The 27 individuals were antiretroviral naive with CD4(+) T-cell counts of >500 cells/ microl for more than 8 years after human immunodeficiency virus type 1 (HIV-1) infection. Effector CTL activity was determined using a standard ex vivo chromium release assay. Individuals with CTL activity (HIV-1 env(IIIB) or pol or gag) were then compared to those without CTL activity in relation to plasma HIV-1 RNA, ICD p24 antigen, beta(2)-microglobulin, CD4 and CD8 T-cell counts, CCR5 and CCR2b genotypes, and progression to CD4 <500 cells/microl or commencement of antiretroviral treatment. Of the 27 individuals examined, 19 had no detectable effector CTL activity. The eight individuals with detectable CTL activity had significantly higher plasma levels of HIV-1 RNA (P = 0.014), immune complex dissociated p24 antigen (P = 0.006), and beta(2)-microglobulin (P = 0.009). There was increased risk of progression within 4 years of study entry in individuals with detectable effector CTL activity, higher plasma levels of HIV-1 RNA, higher beta(2)-microglobulin levels, and higher immune complex dissociated p24 antigen levels at enrollment (P = 0.017, P = 0.004, P = 0.027, P = 0.008 respectively). Multivariate analysis demonstrated viral load remained the strongest predictor of disease progression within this group (P = 0.017). There were no significant associations between CTL response and chemokine receptor genotype. These findings demonstrate the importance of HIV replication in generating an effector CTL response and show that effector CTL activity may be an early predictor of progression in people with long-term asymptomatic HIV infection.     

中国HIV-1感染人群中和抗体水平与疾病进展关系研究

目的 研究中国HIV感染者、AIDS患者及疾病长期不进展者（LTNP）HIV-1中和抗体水平,探讨中和抗体对HIV-1感染疾病进程的影响.方法 提取正常人外周血单个核细胞（PBMC）,应用HIV-1 SF33毒株进行Single-Round PBMC中和试验,流式细胞仪分析CD4＋T细胞内p24-Ag表达.Aleast-squares regression计算中和抗体滴度.结果 HIV感染者、AIDS患者及LTNP中和抗体平均滴度分别为1：29.09、1：22.07、1：154.37.LTNP中和抗体滴度显著高于HIV感染者（t=-2.220,P＜0.05）及AIDS患者（t=-3.812,P＜0.01）;HIV感染者与AIDS患者中和抗体滴度差异无统计学意义（t=0.424,P＞0.05）.结论 中和抗体水平影响中国HIV感染者疾病进展,高水平中和抗体有利于延缓病情进展.     

A combination of defective DNA and protective host factors are found in a set of HIV-1 ancestral LTNPs

We studied viral evolution in three HIV-1 ancestral patients from a group of LTNPs; although some minor sequences showing viral evolution were detected in all patients, the extremely low viral evolution of their viruses was shown by the phylogenetic analysis of the env sequences. Complete nucleotide sequencing of viral DNA showed the major presence of deletions. In two patients, deletions of 1088 and 228 nucleotides mapped to 5′ LTR-gag region; in the other, a 247 nucleotide deletion was positioned in pol gene up to the vif ORF. These deleted genomes became dominant during follow up. Patient's viruses displayed 13 common mutations in conserved residues, from the 5′ LTR to the nef gene. These mutations provided evidence of a common origin. Regarding host characteristics, one patient had HLA B2705/B5801; another B1402/B5701; whereas a third showed B3901/B4402 and was Δ32-CCR5 heterozygous. These HIV controllers presented a combination of deleted viral genomes and host protective factors.     

HIV-infected long-term nonprogressors display a unique correlative pattern between the interleukin-7/interleukin-7 receptor circuit and T-cell homeostasis

Background

We hypothesized that there may be a correlation between the interleukin‐7 (IL‐7)/IL‐7 receptor (IL‐7R) regulatory system and parameters of T‐cell homeostasis in HIV‐infected long‐term nonprogressors (LTNPs) as compared with patients with disease progression.

Methods

The possibility of a correlation between T‐cell homeostatic parameters and IL‐7/IL‐7R was investigated in 22 LTNPs (CD4 count ≥500 cells/μL for >10 years) vs. HIV‐positive patients at different disease stages [12 early: CD4 count ≥400 cells/μL; 15 late (AIDS‐presenters): CD4 count ≤150 cells/μL].

Results

Compared with early‐stage HIV‐positive patients, LTNPs displayed a higher circulating IL‐7 concentration (P=0.05), which was positively associated with higher IL‐7Rα expression and a higher T‐cell receptor excision circle (TREC) content specifically within CD4 cells (P<0.05). Compared with late‐stage disease patients, early‐stage disease patients displayed a lower IL‐7 concentration (P<0.01) and higher percentages of IL‐7Rα⁺ CD4 and CD8 cells (P=0.05). IL‐7 was positively correlated with the percentage of TREC⁺ CD4 cells (P<0.01), which translated into a higher percentage of naïve CD4 cells in early‐stage disease patients than in late‐stage disease patients; however, the CD4 cells in early‐stage disease patients were less enriched in recent thymic emigrants (RTEs) compared with LTNPs (P<0.05). In late‐stage AIDS‐developing patients, substantially increased IL‐7 was correlated with a decreased percentage of IL‐7Rα⁺ CD4 cells (P=0.01), which resulted in these patients having a significantly lower percentage of naïve T cells (P<0.01) and a significantly lower content of TREC (P<0.01) than the other patients.

Conclusions

The maintenance of high CD4 cell counts in LTNPs was associated with a specific IL‐7/IL‐7R pattern characterized by increased IL‐7 and highest IL‐7Rα‐expressing CD4 cells relative to other patients. Compared with patients with late‐stage disease, LTNPs displayed a phenotypically naïve, less activated CD4 cell pool highly enriched in RTEs, suggesting the existence of a compensatory IL‐7‐mediated pathway specifically sustaining peripheral CD4 counts.

     

The expansion ability but not the quality of HIV-specific CD8(+) T cells is associated with protective human leucocyte antigen class I alleles in long-term non-progressors

Studies in long-term non-progressors (LTNP) have suggested that the quality of the CD8(+) response may involve protective human leucocyte antigen (HLA) class I alleles. However, studies examining the expansion ability of different functional CD8(+) T cells and their association with HLA class I alleles are lacking. LTNP, untreated typical progressors (TP) and patients successfully on highly active retroviral therapy (HAART) during 1 year (HP) were included. HLA class I typing was performed using a sequence-specific primer assay. Functional subsets of Gag- and Nef-specific CD8(+) cells were analysed based on the production of macrophage inflammatory protein (MIP)-1β, tumour necrosis factor (TNF)-α and interleukin (IL)-2. Their expansion abilities were evaluated after 10-day culture in the presence of Gag and Nef human immunodeficiency virus (HIV) peptides. No differences were seen when comparing quantitative and qualitative HIV-specific CD8(+) T cell responses according to the presence/absence of protective HLA alleles (B*58 and B*27 supertypes) in each group. However, LTNP with protective HLA alleles showed a higher expansion ability of Gag-specific MIP(+) TNF(+) IL-2(+) T cells and Nef-specific MIP(+) TNF(+) IL-2(+) . HLA-B*5701+LTNP displayed a higher expansion ability of Gag and Nef-specific MIP(+) TNF(-) IL-2(+) T cells than HLA-B*5701-LTNP. This was not so for HLA-B*2705. No differences were seen in the expansion ability according to the presence/absence of protective HLA alleles in TP and HP. The expansion ability of polyfunctional CD8(+) T cells is modulated by HLA class I alleles and targeted protein. LTNP with HLA class I protective alleles (mainly B*5701) display better expansion ability of polyfunctional HIV-specific CD8(+) T cells than the rest, suggesting that factors other than HLA-B*5701 must contribute to the control of viral replication in other LTNP. Furthermore, these attributes of HIV-specific CD8(+) T are not restored by HAART; thus, adjuvant therapies and vaccines that induce and/or normalize the expansion ability of HIV-specific T cells are required.     

Characterization of host genetic expression patterns in HIV-infected individuals with divergent disease progression

The course of HIV-1 infection shows a variety of clinical phenotypes with an important involvement of host factors. We compare host gene expression patterns in CD3+ T cells from two of these phenotypes: long-term non-progressor patients (LTNP) and matched control patients with standard HIV disease progression. Array analysis revealed over-expression of 322 genes in progressors and 136 in LTNP. Up-regulated genes in progressors were mainly implicated in the regulation of DNA replication, cell cycle and DNA damage stimulus and mostly localized into cellular organelles. In contrast, most up-regulated genes in LTNP were located at the plasmatic membrane and involved in cytokine-cytokine receptor interaction, negative control of apoptosis or regulation of actin cytoskeleton. Regarding gene interactions, a higher number of viral genes interacting with cellular factors were seen in progressors. Our study offers new comparative insights related to disease status and can distinguish differentiated patterns of gene expression among clinical phenotypes.     

中国HIV感染长期不进展者T细胞表面IL-7受体表达研究

目的:了解中国HIV感染长期不进展者(Long-Term Non-Progressor,LTNP)T细胞表面IL-7(Interleukin-7,IL-7)受体的表达,分析其与疾病进展的关系。方法:收集LTNP组、HIV组、AIDS组及健康对照组(每组各20例)的抗凝全血,用流式细胞仪检测IL-7受体的表达,并分析IL-7受体表达与血浆中IL-7水平的相关性。结果:LTNP组CD4+T、CD8+T、中枢记忆T细胞(Central memory T cells,Tcm)、效应记忆性T细胞(Effector memory T cells,Tem)表面IL-7受体表达水平明显高于无症状HIV感染组(HIV组)、AIDS病人组(AIDS组)(P<0.05),LTNP组初始T细胞(Na ve T cells,Na ve)、终末分化效应记忆型T细胞(Terminallydifferentiated effector memory T cells,Tem/td)表面IL-7受体表达水平与HIV组、AIDS组间差异无统计学意义。HIV/AIDS患者IL-7受体在CD4+T和CD8+T细胞上表达的百分率与血浆IL-7水平呈明显负相关(P<0.05),与CD4+T细胞数量呈明显的正相关(P<0.05),与病毒载量呈明显负相关(P<0.05)。结论:外周血T细胞表面IL-7受体表达与HIV疾病进展密切相关,LTNP组T细胞保持较高水平的IL-7受体表达,可能是保护因素之一。