HIV Elite Controllers Research Articles

The Breadth of Expandable Memory CD8+ T Cells Inversely Correlates with Residual Viral Loads in HIV Elite Controllers.

Previous studies have shown that elite controllers with minimal effector T cell responses harbor a low-frequency, readily expandable, highly functional, and broadly directed memory population. Here, we interrogated the in vivo relevance of this cell population by investigating whether the breadth of expandable memory responses is associated with the magnitude of residual viremia in individuals achieving durable suppression of HIV infection. HIV-specific memory CD8(+) T cells were expanded by using autologous epitopic and variant peptides. Viral load was measured by an ultrasensitive single-copy PCR assay. Following expansion, controllers showed a greater increase in the overall breadth of Gag responses than did untreated progressors (P = 0.01) as well as treated progressors (P = 0.0003). Nef- and Env-specific memory cells expanded poorly for all groups, and their expanded breadths were indistinguishable among groups (P = 0.9 for Nef as determined by a Kruskal-Wallis test; P = 0.6 for Env as determined by a Kruskal-Wallis test). More importantly, we show that the breadth of expandable, previously undetectable Gag-specific responses was inversely correlated with residual viral load (r = -0.6; P = 0.009). Together, these data reveal a direct link between the abundance of Gag-specific expandable memory responses and prolonged maintenance of low-level viremia. Our studies highlight a CD8(+) T cell feature that would be desirable in a vaccine-induced T cell response. Many studies have shown that the rare ability of some individuals to control HIV infection in the absence of antiretroviral therapy appears to be heavily dependent upon special HIV-specific killer T lymphocytes that are able to inhibit viral replication. The identification of key features of these immune cells has the potential to inform rational HIV vaccine design. This study shows that a special subset of killer lymphocytes, known as central memory CD8(+) T lymphocytes, is at least partially involved in the durable control of HIV replication. HIV controllers maintain a large proportion of Gag-specific expandable memory CD8(+) T cells involved in ongoing viral suppression. These data suggest that induction of this cell subset by future HIV vaccines may be important for narrowing possible routes of rapid escape from vaccine-induced CD8(+) T cell responses.

Potent Cell-Intrinsic Immune Responses in Dendritic Cells Facilitate HIV-1-Specific T Cell Immunity in HIV-1 Elite Controllers.

The majority of HIV-1 elite controllers (EC) restrict HIV-1 replication through highly functional HIV-1-specific T cell responses, but mechanisms supporting the evolution of effective HIV-1-specific T cell immunity in these patients remain undefined. Cytosolic immune recognition of HIV-1 in conventional dendritic cells (cDC) can facilitate priming and expansion of HIV-1-specific T cells; however, HIV-1 seems to be able to avoid intracellular immune recognition in cDCs in most infected individuals. Here, we show that exposure of cDCs from EC to HIV-1 leads to a rapid and sustained production of type I interferons and upregulation of several interferon-stimulated effector genes. Emergence of these cell-intrinsic immune responses was associated with a reduced induction of SAMHD1 and LEDGF/p75, and an accumulation of viral reverse transcripts, but inhibited by pharmacological blockade of viral reverse transcription or siRNA-mediated silencing of the cytosolic DNA sensor cGAS. Importantly, improved cell-intrinsic immune recognition of HIV-1 in cDCs from elite controllers translated into stronger abilities to stimulate and expand HIV-1-specific CD8 T cell responses. These data suggest an important role of cell-intrinsic type I interferon secretion in dendritic cells for the induction of effective HIV-1-specific CD8 T cells, and may be helpful for eliciting functional T cell immunity against HIV-1 for preventative or therapeutic clinical purposes.

Elevated CD4+/CD8+ Ratio in HIV Elite Controller

Elevated CD4+/CD8+ Ratio in HIV Elite Controller

Can HIV Be Cured and Should We Try?

An estimated 35.0 million persons live with HIV; 2.1 million new infections occurred and 1.5 million persons died of HIV in 2013 (World Health Organization, http://www.who.int/hiv/data/epi_core_dec2014.png?ua=1). Despite effective combination antiretroviral therapy (cART), less than one-quarter of patients can access these life-prolonging medications; and despite its effectiveness, cART does not normalize life expectancy, as premature aging, metabolic complications and chronic inflammation complicate HIV therapy. HIV is incurable due to the presence of a latent viral reservoir. During the life cycle of the virus, HIV integrates into the host DNA. A subset of integrated HIV provirus remains transcriptionally silent, producing neither viral proteins nor viral progeny, until reactivation by various physiologic stimuli. This latency of HIV allows some infected cells to escape immune detection and elimination, and these latently infected cells constitute the viral reservoir. The latent viral reservoir allows viral rebound within weeks of interruption of cART, 1,2 where the magnitude of viral replication approaches that present pre-therapy. Although it was once thought that viral rebound occurred universally following therapy interruption, several recent reports challenge that paradigm. The “Berlin patient” successfully cleared HIV after two allogeneic transplants from a donor with homozygous CCR5Δ32 mutation,3 and he has not rebounded HIV after nearly seven years. This case likely represents a cure from HIV; yet other cases have been described where HIV rebound has been attenuated, or delayed. The “Mississippi” baby was a perinatally HIV-infected infant who initiated cART within hours of birth, and when interrupted eighteen months later, viremia remained undetectable for nearly two years.4 The Harvard BMT cases underwent allogeneic BMT, developed undetectable HIV DNA, yet rebounded viremia within only eight months after cART discontinuation.5 Together these cases demonstrate that control of viremia in the absence of cART is possible, if not durable.4 The VISCONTI cohort of 14 HIV-infected adults who initiated antiretroviral therapy during acute infection, and in whom high level rebound viremia had not occurred several years after cessation of therapy,6 similarly demonstrated that viral rebound following cART interruption can be attenuated. These cases have reinvigorated research toward finding a cure for HIV, which certainly will require an exceptional investment of time, talent and resources. Thus it is prudent to question whether such resources would be better devoted to more proximate needs with proven results (such as supplying cART to those without access to it, or supplying pre/post exposure prophylaxis to reduce the rate of new infections).

HIV elite controllers have lower frequencies of CD14dimCD16+ inflammatory monocytes with greater CX3CR1-dependent tissue homing potential than viremic controllers (VIR9P.1138)

Abstract Without antiretroviral therapy, a small fraction of HIV-infected patients does not progress to AIDS. Such elite controllers (EC) or viremic controllers (VC) maintain undetectable or low levels of viremia, respectively. Generation of broadly neutralizing antibodies (bNAb) does not correlate with viral control, but might enhance antibody-dependent cellular phagocytosis by monocytes. Monocytes are classified into CD14+CD16-, CD14+CD16+ and CD14dimCD16+ monocytes. The latter show increased inflammatory responsiveness and are elevated during chronic HIV-1 infection. We measured markers of T cell activation and monocyte subset distribution and quantity, and investigated the relationship between these parameters and production of bNAb to identify markers for the development of bNAbs. We showed that VC display increased frequencies of CD38+ CD4+ and CD8+ T cells compared to EC. Our data also show that elevated frequencies of CD8+CD38+HLA-DR+ T cells and CD14dimCD16+ monocytes were associated with both viremic control status and production of bNAbs. bNAb production was also strongly associated with increased frequency of CD57+HLA-DR+ CD8+ T cells, as well as decreased expression of chemokine receptors CCR2 and CX3CR1 on CD14dimCD16+ monocytes in VC compared to EC. Further studies are required to establish the cause and effect of alterations in monocyte populations during HIV-1 infection and whether these could tip the scale towards viral control below detectable levels.

Characterization of functional antiviral CD8 T cell immune responses of HIV elite controllers by high dimensional phenotyping using mass cytometry (VIR6P.1169)

Abstract Elite controllers (EC) are individuals who control HIV infection without therapy through CD8 T cells. Chronic infections can lead to T cell exhaustion characterized by reduced proliferation and cytokine expression as well as upregulation of co-inhibitory molecules like PD-1. CD8 T cells from EC are more effective at killing HIV-infected targets than those from progressors. The underlying mechanism is not completely understood, but is affected by HLA type, T-cell receptor clonotype, viral epitopes targeted, and likely also by a complex regulatory network of activation and inhibition. However, the particular phenotype of activation and exhaustion markers associated with the increased killing of HIV-specific CD8 T cells from EC has remained unclear. To elucidate these regulatory networks, we performed high-dimensional phenotyping of HIV-specific CD8 T cells using mass cytometry (CyTOF), a cutting edge technology combining flow cytometry and mass spectrometry that enables analysis of up to 40 markers with minimal signal overlap. We established and validated a CyTOF panel of 33 markers to identify up to 6 HIV-specific CD8 T-cell subsets using tetramer technology and characterize memory, activation and exhaustion status of those cells. Use of our panel enables the in-depth characterization of HIV-specific CD8 T cells at a level of unprecedented granularity and may reveal signatures of activation and exhaustion networks that underlie the enhanced lytic capacity of these cells in EC.

HIV controllers with different viral load cutoff levels have distinct virologic and immunologic profiles.

The mechanisms behind natural control of HIV replication are still unclear, and several studies pointed that elite controllers (ECs) are a heterogeneous group. We performed analyses of virologic, genetic, and immunologic parameters of HIV-1 controllers groups: (1) ECs (viral load, <80 copies/mL); (2) ebbing elite controllers (EECs; transient viremia/blips); and viremic controllers (VCs; detectable viremia, <5000 copies/mL). Untreated noncontrollers (NCs), patients under suppressive highly active antiretroviral therapy (HAART), and HIV-1-negative individuals were analyzed as controls. Total and integrated HIV-1 DNA for EC were significantly lower than for NC and HAART groups. 2-LTR circles were detected in EEC (3/5) and VC (6/7) but not in EC. Although EC and EEC maintain normal T-cell counts over time, some VC displayed negative CD4 T-cell slopes. VC and EEC showed a higher percentage of activated CD8 T cells and microbial translocation than HIV-1-negative controls. EC displayed a weaker Gag/Nef IFN-γ T-cell response and a significantly lower proportion of anti-HIV IgG antibodies than EEC, VC, and NC groups. Transient/persistent low-level viremia in HIV controllers may have an impact on immunologic and virologic profiles. Classified HIV controller patients taking into account their virologic profile may decrease the heterogeneity of HIV controllers cohorts, which may help to clarify the mechanisms associated to the elite control of HIV.

Anti-APOBEC3G activity of HIV-1 Vif protein is attenuated in elite controllers.

HIV-1-infected individuals who control viremia to below the limit of detection without antiviral therapy have been termed elite controllers (EC). Functional attenuation of some HIV-1 proteins has been reported in EC. The HIV-1 accessory protein Vif (virion infectivity factor) enhances viral infectivity through anti-retroviral factor apolipoprotein B mRNA editing enzyme catalytic polypeptide-like 3G (APOBEC3G) degradation; however, little is known regarding Vif function in EC. Here, the anti-APOBEC3G activities of clonal, plasma HIV RNA-derived Vif sequences from 46 EC, 46 noncontrollers (NC), and 44 individuals with acute infection (AI) were compared. Vesicular stomatitis virus glycoprotein (VSV-G)-pseudotyped viruses were generated by cotransfecting 293T cells with expression plasmids encoding patient-derived Vif, human APOBEC3G, VSV-G, and a vif/env-deficient luciferase-reporter HIV-1 proviral DNA clone. Viral stocks were used to infect 293T cells, and Vif anti-APOBEC3G activity was quantified in terms of luciferase signal. On average, the anti-APOBEC3G activities of EC-derived Vif sequences (median log10 relative light units [RLU], 4.54 [interquartile range {IQR}, 4.30 to 4.66]) were significantly lower than those of sequences derived from NC (4.75 [4.60 to 4.92], P < 0.0001) and AI (4.74 [4.62 to 4.94], P < 0.0001). Reduced Vif activities were not associated with particular HLA class I alleles expressed by the host. Vif functional motifs were highly conserved in all patient groups. No single viral polymorphism could explain the reduced anti-APOBEC3G activity of EC-derived Vif, suggesting that various combinations of minor polymorphisms may underlie these effects. These results further support the idea of relative attenuation of viral protein function in EC-derived HIV sequences. HIV-1 elite controllers (EC) are rare individuals who are able to control plasma viremia to undetectable levels without antiretroviral therapy. Understanding the pathogenesis and mechanisms underpinning this rare phenotype may provide important insights for HIV vaccine design. The EC phenotype is associated with beneficial host immunogenetic factors (such as HLA-B*57) as well as with functions of attenuated viral proteins (e.g., Gag, Pol, and Nef). In this study, we demonstrated that HIV-1 Vif sequences isolated from EC display relative impairments in their ability to counteract the APOBEC3G host restriction factor compared to Vif sequences from normal progressors and acutely infected individuals. This result extends the growing body of evidence demonstrating attenuated HIV-1 protein function in EC and, in particular, supports the idea of the relevance of viral factors in contributing to this rare HIV-1 phenotype.

Human X-DING-CD4 mediates resistance to HIV-1 infection through novel paracrine-like signaling.

X-DING-CD4 is a novel phosphatase mediating antiviral responses to HIV-1 infection. This protein is constitutively expressed and secreted by HIV-1 resistant CD4(+) T cells and its mRNA transcription is up-regulated in peripheral blood mononuclear cells from HIV-1 elite controllers. The secreted/soluble X-DING-CD4 protein form is of particular importance because it blocks virus transcription when added to HIV-1 susceptible cells. The present study aimed to determine the contribution of this factor to the induction of the antiviral response in target cells. We found that soluble X-DING-CD4 enters cells by endocytosis and that influx of this protein induced transcription of interferon-α and endogenous X-DING-CD4 mRNA in transformed CD4(+) T cells and primary macrophages. Treatment of HIV-1 susceptible cells with exogenous X-DING-CD4 caused depletion of phosphorylated p50 and p65 nuclear factor kappa β subunits and a significant reduction in p50/p65 nuclear factor kappa β binding to the HIV-1 long terminal repeat. Taken together, these findings indicate a novel antiviral mechanism mediated by the influx of soluble X-DING-CD4, its signaling to promote self-amplification, and functional duality as an endogenous innate immunity effector and exogenous factor regulating gene expression in bystander cells.

Hospitalization Rates and Reasons Among HIV Elite Controllers and Persons With Medically Controlled HIV Infection.

Elite controllers spontaneously suppress human immunodeficiency virus (HIV) viremia but also demonstrate chronic inflammation that may increase risk of comorbid conditions. We compared hospitalization rates and causes among elite controllers to those of immunologically intact persons with medically controlled HIV. For adults in care at 11 sites from 2005 to 2011, person-years with CD4 T-cell counts ≥350 cells/mm(2) were categorized as medical control, elite control, low viremia, or high viremia. All-cause and diagnostic category-specific hospitalization rates were compared between groups using negative binomial regression. We identified 149 elite controllers (0.4%) among 34 354 persons in care. Unadjusted hospitalization rates among the medical control, elite control, low-viremia, and high-viremia groups were 10.5, 23.3, 12.6, and 16.9 per 100 person-years, respectively. After adjustment for demographic and clinical factors, elite control was associated with higher rates of all-cause (adjusted incidence rate ratio, 1.77 [95% confidence interval, 1.21-2.60]), cardiovascular (3.19 [1.50-6.79]) and psychiatric (3.98 [1.54-10.28]) hospitalization than was medical control. Non-AIDS-defining infections were the most common reason for admission overall (24.1% of hospitalizations) but were rare among elite controllers (2.7%), in whom cardiovascular hospitalizations were most common (31.1%). Elite controllers are hospitalized more frequently than persons with medically controlled HIV and cardiovascular hospitalizations are an important contributor.

Short communication: Plasmacytoid dendritic cells from HIV-1 Elite Controllers maintain a gut-homing phenotype associated with immune activation.

Lentivirus infections are characterized by a dramatic loss of mucosal CD4(+) T cells, breakdown of the gut mucosa, and subsequent chronic immune activation. Residual immune activation persists even in patients controlling virus replication and remains a significant source of ongoing disease morbidities, but the causes are unclear. Plasmacytoid dendritic cells (pDCs), primary producers of interferon (IFN)-α, have been previously shown to be depleted from peripheral blood of HIV patients and simian immunodeficiency virus (SIV)-infected macaques, and most recently have been shown to accumulate in the gut mucosa. Although previous work has shown that pDC frequencies can be reduced in the circulation of HIV-1 Elite Controllers, it is unknown if gut-homing also occurs. In this new study we found that during progressive HIV-1 infection pDCs were depleted in peripheral blood compared to seronegative controls, and, correlating with plasma viremia, the remaining pDCs upregulated the gut-homing marker, α4β7. Even in HIV-1 Elite Controllers pDCs were significantly reduced in blood and α4β7 expression was still significantly upregulated compared to seronegative controls. Interestingly, pDC trafficking to the gut was associated with increased Ki67 and HLA-DR on circulating CD4(+) and CD8(+) T cells. Overall, these data suggest that gut trafficking of pDCs is independent of virus replication and could be mediated by alternative mechanisms, which in turn could contribute to residual immune activation in HIV-1 Elite Controllers.

A Distinct Treg Transcriptome Signature in HIV-1 Elite Controllers Might Contribute to Improved Disease Outcome

A Distinct Treg Transcriptome Signature in HIV-1 Elite Controllers Might Contribute to Improved Disease Outcome

A follow-up study of HIV long-term non-progress populations in Henan province

To explore the related testing indicators variation of HIV long-term non-progress populations. The long-term non-progress populations in some areas of Henan were recruited, and the study was carried out according to different CD4(+)T lymphocytes counts for two groups. The dynamic characteristics of immune status and viral load between LTNP-1group (CD4(+)T lymphocytes ≥ 500/µl, 42 cases) and LTNP-2 group(350/µl ≤ CD4(+)T lymphocytes < 500/µl, 49 cases) from July 2010 to August 2013 were observed. The characteristics of HIV elite controllers during the follow-up were also described. LTNP were recruited, 56% (51 cases) were men, and 44% (40 cases) were women. The study population were aged from 38 to 65 years old. A total of 320 individuals were followed-up, 14 cases were lost, 2 deaths, and 16 cases had received antiretroviral therapy during four years. To analyze the annual changes of CD4(+)T lymphocytes and VL of the group from 2010 to 2013, LTNP-1 group CD4(+)T lymphocytes from 654.0(545.2-809.5) decreased to 494.0(341.0-574.7), and LTNP-2 group decreased from 493.0 (429.5-770.0) to 343.5(253.0-500.8), CD4(+)T lymphocytes decline of over times of two groups in longitudinal analysis (χ(2) = 50.32, P < 0.01; χ(2) = 31.03, P < 0.01). lg (VL) of LTNP-1 group were 3.52 (3.15-4.27), 3.71 (2.70-4.55), 3.86 (3.59-4.55), 3.96 (3.25-4.36), and lg (VL) of TNP-2 group were 4.35 (3.72-4.83), 4.35 (3.97-4.94), 4.71 (3.96-4.95), 5.04(4.78-5.26), respectively (P > 0.05). The same year inter-group comparison found CD4(+)T lymphocytes of LTNP-1 group were higher than LTNP-2 group (Z = 5.23, P < 0.01; Z = 3.06, P < 0.01; Z = 2.51, P < 0.05; Z = 2.47, P < 0.05). VL of LTNP-2 group increased from 4.35(3.97-4.94) to 5.04 (4.78-5.26) during 2011 to 2013, were higher than LTNP-1 group in the same year (Z = 2.28, P < 0.05; Z = 2.58, P < 0.05; Z = 2.76, P < 0.05). 65 cases HCV antibody were positive in 91 individuals, and the HCV antibody positive rate was 76% (32/42), 67% (33/49) between LTNP-1 group and LTNP-2 group. Six elite controllers maintained CD4(+)T lymphocytes ≥ 500/µl, VL<1 000 copies/ml during four years follow-up. The long-term non-progress populations in Henan were overall healthy, and VL were relatively stable, there was a decreased trend of CD4 year by year, and HCV co-infection rate was high.

Increased expression of SAMHD1 in a subset of HIV-1 elite controllers

SAMHD1 and the CDKN1A (p21) cyclin-dependent kinase inhibitor have been postulated to mediate HIV-1 restriction in CD4+ cells. We have shown that p21 affects HIV replication through its effect on SAMHD1. Thus, we aimed at evaluating the expression of SAMHD1 and p21 in different HIV+ phenotypic groups. We evaluated SAMHD1 and CDKN1A mRNA expression in CD4+ T cells from HIV+ individuals including elite controllers (n = 12), individuals who control HIV without the need for antiretroviral treatment, viraemic progressors (n = 10) and HIV-1 seronegative healthy donors (n = 14). Immunological variables were measured by flow cytometry. We show that a subset of HIV+ elite controllers with lower T cell proliferation levels (Ki67+ cells) expressed higher SAMHD1 compared with healthy donors or viraemic progressors. Conversely, there was no difference in p21 expression before or after T cell activation with a bispecific CD3/CD8 antibody. Our results suggest that SAMHD1 may play a role in controlling virus replication in HIV+ individuals and slow the rate of disease progression.

An Evaluation of HIV Elite Controller Definitions within a Large Seroconverter Cohort Collaboration

BackgroundUnderstanding the mechanisms underlying viral control is highly relevant to vaccine studies and elite control (EC) of HIV infection. Although numerous definitions of EC exist, it is not clear which, if any, best identify this rare phenotype.MethodsWe assessed a number of EC definitions used in the literature using CASCADE data of 25,692 HIV seroconverters. We estimated proportions maintaining EC of total ART-naïve follow-up time, and disease progression, comparing to non-EC. We also examined HIV-RNA and CD4 values and CD4 slope during EC and beyond (while ART naïve).ResultsMost definitions classify ∼1% as ECs with median HIV-RNA 43–903 copies/ml and median CD4>500 cells/mm3. Beyond EC status, median HIV-RNA levels remained low, although often detectable, and CD4 values high but with strong evidence of decline for all definitions. Median % ART-naïve time as EC was ≥92% although overlap between definitions was low. EC definitions with consecutive HIV-RNA measurements <75 copies/ml with follow-up≥ six months, or with 90% of measurements <400 copies/ml over ≥10 year follow-up preformed best overall. Individuals thus defined were less likely to progress to endpoint (hazard ratios ranged from 12.5–19.0 for non-ECs compared to ECs).ConclusionsECs are rare, less likely to progress to clinical disease, but may eventually lose control. We suggest definitions requiring individuals to have consecutive undetectable HIV-RNA measurements for ≥ six months or otherwise with >90% of measurements <400 copies/ml over ≥10 years be used to define this phenotype.

Blunted Response to Combination Antiretroviral Therapy in HIV Elite Controllers: An International HIV Controller Collaboration

ObjectiveHIV “elite controllers” (ECs) spontaneously control viral load, but some eventually require combination antiretroviral treatment (cART), due to a loss of viral control or a decline in CD4 T-cell counts. Here we studied the CD4 T-cell count dynamics after cART initiation among 34 ECs followed in U.S. and European cohorts, by comparison with chronically viremic patients (VIRs).MethodsECs were defined as patients with at least ≥5 viral load (VL) measurements below 400 copies/mL during at least a 5-year period despite never receiving ART and were selected from the French ANRS CO18 cohort, the U.S. SCOPE cohort, the International HIV Controllers study and the European CASCADE collaboration. VIRs were selected from the ANRS COPANA cohort of recently-diagnosed (<1 year) ART-naïve HIV-1-infected adults. CD4 T-cell count dynamics after cART initiation in both groups were modelled with piecewise mixed linear models.ResultsAfter cART initiation, CD4 T-cell counts showed a biphasic rise in VIRs with: an initial rapid increase during the first 3 months (+0.63/month), followed by +0.19/month. This first rapid phase was not observed in ECs, in whom the CD4Tc count increased steadily, at a rate similar to that of the second phase observed in VIRs. After cART initiation at a CD4 T-cell count of 300/mm3, the estimated mean CD4 T-cell gain during the first 12 months was 139/mm3 in VIRs and 80/mm3 in ECs (p = 0.048).ConclusionscART increases CD4 T-cell counts in elite controllers, albeit less markedly than in other patients.

Correction: Distinct Tryptophan Catabolism and Th17/Treg Balance in HIV Progressors and Elite Controllers

Errors occurred in Table 2. The correct values for the last row IL-6 (pg/ml) in Table 2 are incorrect. The correct values are: ST : 1.94±0.81, ART-Naive: 3.61±0.71, EC: 1.37±0.30, HS: 1.26±0.27, p value: 0.0089

Glycoproteomic Study Reveals Altered Plasma Proteins Associated with HIV Elite Suppressors

HIV elite suppressors (ES) or controllers are individuals achieving control of viremia by their natural immunological mechanisms without highly active antiretroviral therapy (HAART). Study of the mechanisms responsible for the immunological suppression of viremia in ES may lead to the detection of individuals with ES and the effective control of HIV infection. We hypothesize that plasma glycoproteins play essential roles in the immune system of ES since plasma proteins are critical and highly relevant in anti-viral immunity and most plasma proteins are glycoproteins. To examine glycoproteins associated with ES, plasma samples from ES individuals (n=20), and from individuals on HAART (n=20), with AIDS (n=20), and no HIV infection (n=10) were analyzed by quantitative glycoproteomics. We found that a number of glycoproteins changed between ES versus HAART, AIDS and HIV- individuals. In sharp contrast, the level of plasma glycoproteins in the HAART cohort showed fewer changes compared with AIDS and HIV- individuals. These results showed that although both ES and HAART effectively suppress viremia, ES appeared to profoundly affect immunologically relevant glycoproteins in plasma as consequence of or support for anti-viral immunity. Bioinformatic analysis revealed that altered proteins in ES plasma were mainly associated with inflammation. This analysis suggests that overlapping, while distinguishable, glycoprotein profiles for inflammation and immune activation appeared to be present between ES and non-ES (HAART+AIDS) cohorts, indicating different triggers for inflammation and immune activation between natural and treatment-related viral suppression.

Retrospective proteomic analysis of cellular immune responses and protective correlates of p24 vaccination in an HIV elite controller

BackgroundHIV p24 is an extracellular HIV antigen that is involved in viral replication. Falling p24 antibody responses are associated with clinical disease progression, whereas their preservation with non-progression implies that stimulation of p24 antibody production by immunisation might delay progression. This was the basis of the discontinued p24 vaccine. We identified a therapy-naive man aged 61 years from Sydney, Australia, infected in 1988 through his partner. He received the HIV-p24-virus like particle (VLP) vaccine and a 3 week course of azidothymidin monotherapy in 1993, and continued to show vigorous p24 antigen responses with more than 4% p24-specific CD4+ T cells, coupled with undetectable plasma viraemia, until December, 2011. The patient has since remained therapy naive, with plasma viraemia below detectable levels. The patient is heterozygous for CCR5Δ32 and has an HLA type A1, 2; B8, 44; DR4, 15. In 2011, a transitory viral spike (163 HIV RNA copies per mL plasma) was recorded, which without antiretroviral drug treatment reverted to undetectable virus (<20 HIV copies per mL) in 3 weeks. We aimed to define the immune-protective correlates of p24 vaccination in this individual by retrospective analysis of cellular responses to p24 antigen in CD4+ and CD8+ T cells, and CD14+ monocytes, in terms of the concentrations of 270 cytokines and chemokines during viraemia and aviraemia. MethodsWe used whole peripheral blood mononuclear cells from the two phases, stimulated them with p24 antigen, and then separated them by magnetic beads as stimulated and unstimulated CD4+ and CD8+ T cells, and monocyte fractions. Cellular proteins were extracted, quantified, and analysed with a cytokine antibody array. Differentially expressed proteins were analysed with online bioinformatic tools, and statistics evaluated with the student t test and three k-way analyses. FindingsEncompassing all three cell types, we found statistically significant coordinated upregulation with high fold-changes of fractalkine, ITAC, IGFBP-2, cathepsin-S, and CCL14a in the aviraemic phase. TECK and TRAIL-R4 were downregulated in the viraemic phase and upregulated in the aviraemic phase. Fractalkine, which showed high fold-changes across cell types during the aviraemic phase and no expression during viraemia, plays a vital part in promotion of cell survival during homeostatic and inflammatory conditions. The upregulation of fractalkine in all three cell types (14-fold in CD4+ T cells, 12-fold in monocytes, and five-fold in CD8+ T cells) during aviraemia might be associated with a protective effect. Interestingly, downregulation of TRAIL-R3/R4 and TECK/CCL25 coincided with plasma viraemia and their upregulation with aviraemia, suggesting that dysfunction in antiapoptotic chemokines might be a mechanism contributing to loss of immune function during HIV infection, and that an effective T-cell-derived immune response can be mounted without T-cell exhaustion. Decrease in TECK expression is associated with increased apoptosis in lymphoid tissues in macaques infected with simian immunodeficiency virus. InterpretationBecause the p24 VLP vaccine failed to induce antibody titres, the possible beneficial effect of p24 vaccine in this individual could be attributed to broad and coordinated cellular responses mounted by all three cell types in tandem in modulating viraemic and aviraemic phases. This study highlights that induction of HIV-1-specific helper cells might be important in immunotherapeutic interventions and HIV vaccine development. FundingWe acknowledge the support of a National Health and Medical Research Council Development grant to NKS.

Distinct Tryptophan Catabolism and Th17/Treg Balance in HIV Progressors and Elite Controllers

Tryptophan (Trp) catabolism into immunosuppressive kynurenine (Kyn) by indoleamine 2,3-dioxygenase (IDO) was previously linked to Th17/Treg differentiation and immune activation. Here we examined Trp catabolism and its impact on Th17/Treg balance in uninfected healthy subjects (HS) and a large cohort of HIV-infected patients with different clinical outcomes: ART-naïve, Successfully Treated (ST), and elite controllers (EC). In ART-naïve patients, increased IDO activity/expression, together with elevated levels of TNF-α and sCD40L, were associated with Treg expansion and an altered Th17/Treg balance. These alterations were normalized under ART. In contrast, Trp 2,3-dioxegenase (TDO) expression was dramatically lower in EC when compared to all other groups. Interestingly, EC displayed a distinctive Trp metabolism characterized by low Trp plasma levels similar to ART-naïve patients without accumulating immunosuppressive Kyn levels which was accompanied by a preserved Th17/Treg balance. These results suggest a distinctive Trp catabolism and Th17/Treg balance in HIV progressors and EC. Thus, IDO-induced immune-metabolism may be considered as a new inflammation-related marker for HIV-1 disease progression.