CD4＋T淋巴细胞增殖与艾滋病疾病进展的关系研究

目的探讨CD4＋T淋巴细胞增殖与中国艾滋病病毒（HIV-1）感染者疾病进展的关系。方法用羧基荧光素乙酰乙酸（CFSE）示踪染色法,检测中国正常人、感染HIV-1的典型进展者（TP）和长期不进展者（LTNP）CD4＋T淋巴细胞增殖情况,并对三组人群CD4＋T淋巴细胞的增殖能力进行比较。结果与正常人对照相比,TP和LT-NP病例的CD4＋T淋巴细胞增殖系数（PI）和CFSElowCD4＋T淋巴细胞比例均明显降低（P〈0.01,P〈0.05;P〈0.01,P〈0.01）;其中TP病例的PI和CFSElowCD4＋T淋巴细胞的比例又低于LTNP病例（P〈0.01,P〈0.01）。对于HIV-1感染者（包括TP和LTNP病例）,CFSElowCD4＋T淋巴细胞比例和PI与CD4＋T淋巴细胞计数均呈正相关（R=0.946,P〈0.01;R=0.585,P〈0.05）,与病毒载量均呈负相关（R=-0.634,P〈0.05;R=-0.528,P〈0.05）。结论 CD4＋T淋巴细胞增值能力和艾滋病疾病进展相关,CD4＋T淋巴细胞保持较高的增殖能力,对中国HIV-1感染者长期不进展是一种保护因素。     

长期不进展者与艾滋病患者HIV-1 nef特异性CD8+ T细胞应答的初步研究

目的　探讨我国HIV 1nef特异性CD8 T细胞应答的特点及其免疫保护作用。方法以长期不进展组 (LTNP) 7例和艾滋病组 9例为研究对象 ,以覆盖HIV 1nef全长的 2 6个重叠肽段组成的 3个肽段库作为刺激原 ,用IFN ELISPOT方法检测LTNP组与艾滋病组患者HIV 1nef特异性CD8 T细胞应答 ,并测定其CD4 T细胞、CD8 T细胞和病毒载量 ,观察两组间HIV 1nef特异性CD8 T细胞应答的差异及其与CD4 T细胞和病毒载量的相关性。结果　LTNP组和艾滋病组HIV 1nef特异性CD8 T细胞应答的强度分别为 4 0 4± 334和 5 9± 12 1SFC/ 10 6外周血单个核细胞 (PBMC) ,LTNP组显著高于艾滋病组 ;HIV 1nef特异性CD8 T细胞应答的强度与CD4 T细胞计数呈正相关 ,但与病毒载量没有显著的相关性。结论　HIV 1nef特异性CD8 T细胞应答在艾滋病发病中具有一定的保护作用 ,欧美流行株与我国流行株之间具有免疫交叉反应性     

Associations of HLA Class I antigen specificities and haplotypes with disease progression in HIV-1-infected Hans in Northern China

The human leukocyte antigen (HLA) allele frequencies, which differ among various ethnic populations, may result in population-specific effects on HIV-1 disease progression. No large-scale study has yet been conducted on the Chinese population. In this study, HLA class I antigen specificities were determined in a cohort including 105 long-term non-progressors (LTNPs) and 321 typical progressors (TPs), who were recruited from HIV-1-infected Northern Han Chinese, to determine the associations between certain HLA types and HIV-1 disease progression. The frequencies of HLA class I specificities and haplotypes among the two groups were compared using binary logistic stepwise regression. Results showed that HLA-A^∗30-B^∗13-C^∗06 (OR = 0.387, P = 0.019) and B^∗67 (OR = 0.134, P = 0.005) were associated with a long-term non-progressing condition, and C^∗01 (OR = 2.539, P = 0.050) was overrepresented in TPs after adjusting for non-genetic factors (sex, age, the location of patients, HIV subtype and the route of infection). The influence of HLA homozygosity on HIV disease progression was also analyzed. However, homozygosity at HLA-A, HLA-B or HLA-C conferred no observable disadvantage in our study population (P = 0.730, 0.246 and 0.445, respectively). These findings suggest that the host’s genetics make important contributions to HIV viral control and may help to develop peptide-based vaccines for this population.     

CD8+CD28−CD127loCD39+ regulatory T-cell expansion: A new possible pathogenic mechanism for HIV infection?

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Heteroclitic peptides enhance human immunodeficiency virus-specific CD8 T cell responses

The inability of human immunodeficiency virus (HIV)-specific CD8⁺ T cells to durably control HIV replication due to HIV escape mutations and CD8⁺ T cell dysfunction is a key factor in disease progression. A few HIV-infected individuals termed elite controllers (EC) maintain polyfunctional HIV-specific CD8⁺ T cells, minimal HIV replication and normal CD4⁺ T lymphocyte numbers. Thus, therapeutic intervention to sustain or restore CD8⁺ T cell responses similar to those persisting in EC could relieve terminal dependence on antiretrovirals. Vaccination with HIV peptides is one approach to achieve this and our objective in this study was to determine whether certain HIV peptide variants display antigenic superiority over the reference peptides normally included in vaccines. Eight peptide sets were generated, each with a reference peptide and six variants harboring conservative or semi-conservative amino acid substitutions at positions predicted to affect T cell receptor interactions without affecting human class I histocompatibililty-linked antigen (HLA) binding. Recognition across peptide sets was tested with >80 HIV-infected individuals bearing the appropriate HLA alleles. While reference peptides were often the most antigenic, cross-reactivity with variants was common and in many cases, peptide variants were superior at stimulating interferon-γ production or selectively enhanced interleukin-2 production. Although such heteroclitic activity was not generalized for all individuals bearing the HLA class I allele involved, these data suggest that heteroclitic peptide variants could improve the efficacy of therapeutic peptide vaccines in HIV infection.     

Safety and immunogenicity of an adjuvanted protein therapeutic HIV-1 vaccine in subjects with HIV-1 infection: A randomised placebo-controlled study

The human immunodeficiency virus type-1 (HIV-1) vaccine candidate F4/AS01 has previously been shown to induce potent and persistent polyfunctional CD4⁺ T-cell responses in HIV-1-seronegative volunteers. This placebo-controlled study evaluated two doses of F4/AS01 1-month apart in antiretroviral treatment (ART)-experienced and ART-naïve HIV-1-infected subjects (1:1 randomisation in each cohort). Safety, HIV-1-specific CD4⁺ and CD8⁺ T-cell responses, absolute CD4⁺ T-cell counts and HIV-1 viral load were monitored for 12 months post-vaccination. Reactogenicity was clinically acceptable and no vaccine-related serious adverse events were reported. The frequency of HIV-1-specific CD4⁺ T-cells 2 weeks post-dose 2 was significantly higher in the vaccine group than in the placebo group in both cohorts (p < 0.05). Vaccine-induced HIV-1-specific CD4⁺ T-cells exhibited a polyfunctional phenotype, expressing at least CD40L and IL-2. No increase in HIV-1-specific CD8⁺ T-cells or change in CD8⁺ T-cell activation marker expression profile was detected. Absolute CD4⁺ T-cell counts were variable over time in both cohorts. Viral load remained suppressed in ART-experienced subjects. In ART-naïve subjects, a transient reduction in viral load from baseline was observed 2 weeks after the second F4/AS01 dose, which was concurrent with a higher frequency of HIV-1-specific CD4⁺ T-cells expressing at least IL-2 in this cohort. In conclusion, F4/AS01 showed a clinically acceptable reactogenicity and safety profile, and induced polyfunctional HIV-1-specific CD4⁺ T-cell responses in ART-experienced and ART-naïve subjects. These findings support further clinical investigation of F4/AS01 as a potential HIV-1 vaccine for therapeutic use in individuals with HIV-1 infection.     

p6gag of human and simian immunodeficiency viruses is tolerant to small in-frame deletions downstream of the late domain

Short, unique, in-frame deletions were consistently detected within p6gag sequences obtained over time from three of eight HIV-1-infected long-term nonprogressors (Alexander, L., Weiskopf, E., Greenough, T.C., Gaddis, N.C., Auerbach, M.R., Malim, M.H., O'Brien, S.J., Walker, B.D., Sullivan, J.L., Desrosiers, R.C., 2000. Unusual polymorphisms in Human Immunodeficiency Virus Type 1 associated with nonprogressive infection. J. Virol. 74, 4361-4376). Using PCR mutagenesis, we created 11 mutant forms of SIV239 and 8 mutant forms of HIV-1 NL4-3 with serial 2 amino acid deletions within p6gag downstream of the PTAP late domain. Nine of the 11 SIV239 mutants assembled and released virion particles similar to wild-type, displayed wild-type infectivity, and replicated similar to wild-type SIV239 in cultured cells. Two of the 11 SIV239 mutants, both involving D at position 21, were grossly defective for intracellular gag accumulation and did not replicate detectably in cultured cells. Similar to the 9 SIV239 mutants, 7 of the 8 HIV-1 mutants replicated well in cultured cells. Only the mutant deleted of ES at positions 19 and 20, immediately adjacent to the PTAP sequence, was markedly impaired in its replicative capacity. These results demonstrate an overall high tolerance of SIV and HIV to two amino acid deletions within p6gag downstream of the late domain.     

High levels of anti-Nef antibodies may prevent AIDS disease progression in vertically HIV-1-infected infants

Introduction

HIV-1-associated CD4+ T-cell depletion is a consequence of uninfected cell death. Nef is one of the viral factors that trigger apoptosis on bystander cells, though the plasma Nef levels do not correlate with Th lymphocytes counts. The aim of our study was to evaluate whether anti-Nef antibodies were involved in paediatric AIDS development and whether they can prevent the CD4+ T-cell depletion in vertically infected children.

Methods

Two hundred and seventy three HIV-1 vertically infected children seen at Garrahan Paediatric Hospital were randomly included in the study, adding 13 selected cases: seven LTNP (long-term non-progressors) and six RP (rapid progressors) children (n _total=286). Specific anti-HIV-1-Nef antibodies were titrated by indirect ELISA and compared between groups. The plasma blocking effect on Nef-dependent cytotoxicity was evaluated in Jurkat cells using recombinant Nef as apoptotic stimulus and patient plasmas as blockers, measuring the apoptotic levels using Annexin-V stain and flow cytometry.

Results

Only 63.4% of the patients had specific anti-Nef antibodies, and the levels of anti-Nef antibodies found in the selected LTNPs plasmas were always significantly higher (p=1.55×10⁻⁴) than those in RPs or general HIV-1+ paediatric populations. The LTNPs’ plasma had a strong inhibitory effect on Nef-dependent cytotoxicity even at high dilutions, while RP plasmas had little or no effect on Nef-induced apoptosis.

Discussion and conclusions

High anti-Nef antibody levels are associated and predict slow or non-progression to AIDS in vertically HIV-1-infected children. They could be an efficient tool in preventing Nef-associated bystander effect, preserving CD4+ T-cells and the immune function in the context of paediatric HIV-1 infection.     

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.