Browsing by Author "Falivene, Juliana"

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    Biomarkers of Progression after HIV Acute/Early Infection: Nothing Compares to CD4+ T-cell Count?
    (2018-01-13) Turk, Gabriela; Ghiglione, Yanina; Hormanstorfer, Macarena; Laufer, Natalia; Coloccini, Romina; Salido, Jimena; Trifone, César; Ruiz, Maria; Falivene, Juliana; Holgado, María Pía; Caruso, María Paula; Figueroa, María Inés; Salomon, Horacio ; Giavedoni, Luis D; De los Ángeles Pando, María; Gherardi, María Magdalena; Rabinovich, Roberto Daniel; Pury, Pedro A; Sued, Omar
    Progression of HIV infection is variable among individuals, and definition disease progression biomarkers is still needed. Here, we aimed to categorize the predictive potential of several variables using feature selection methods and decision trees. A total of seventy-five treatment-naïve subjects were enrolled during acute/early HIV infection. CD4+ T-cell counts (CD4TC) and viral load (VL) levels were determined at enrollment and for one year. Immune activation, HIV-specific immune response, Human Leukocyte Antigen (HLA) and C-C chemokine receptor type 5 (CCR5) genotypes, and plasma levels of 39 cytokines were determined. Data were analyzed by machine learning and non-parametric methods. Variable hierarchization was performed by Weka correlation-based feature selection and J48 decision tree. Plasma interleukin (IL)-10, interferon gamma-induced protein (IP)-10, soluble IL-2 receptor alpha (sIL-2Rα) and tumor necrosis factor alpha (TNF-α) levels correlated directly with baseline VL, whereas IL-2, TNF-α, fibroblast growth factor (FGF)-2 and macrophage inflammatory protein (MIP)-1β correlated directly with CD4+ T-cell activation (p < 0.05). However, none of these cytokines had good predictive values to distinguish “progressors” from “non-progressors”. Similarly, immune activation, HIV-specific immune responses and HLA/CCR5 genotypes had low discrimination power. Baseline CD4TC was the most potent discerning variable with a cut-off of 438 cells/μL (accuracy = 0.93, κ-Cohen = 0.85). Limited discerning power of the other factors might be related to frequency, variability and/or sampling time. Future studies based on decision trees to identify biomarkers of post-treatment control are warrantied.
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    Distribution of Bulk and HIV-specific CD8 + T Cell Memory Phenotypes during Acute/Early HIV Infection Is Related to Reduced Antiviral Activity
    (2014) Ghiglione, Yanina; Falivene, Juliana; Ruiz, Maria; Laufer, Natalia; Socias, Maria E.; Cahn, Pedro; Sued, Omar; Salomon, Horacio; Gherardi, María Magdalena; Turk, Gabriela
    Background: Memory CD8+ T-cells are important components of protective immunity. Understanding their development during primary HIV infection (PHI) may contribute to optimal vaccine design. Aim: To analyze the distribution of memory subsets during PHI and their correlation with functionality and clinical parameters. Methods: 19 samples from acutely infected subjects were obtained at baseline and 12 months post-infection (mpi). Phenotypic (CD45RO, CCR7, PD-1) and functional markers (cytokines) were used to identify bulk and HIV-specific CD8+ memory populations. CD8 virus inhibitory assay (VIA) was performed. Data was compared intra-group and correlated to clinical parameters, PD-1 analysis and CD8 antiviral activity, using non-parametric statistics. Results: Bulk and HIV-specific CD8+ profile was terminal effectors (TE)>naïve>effector memory (TEM)>central memory. Spearman's correlation showed that baseline CD8+ VIA inversely correlated with the concurrent proportion of HIV-specific CD8+ TEM cells (r=-0.593, p=0.009) and directly correlated with the proportion of HIV-specific CD8+ TE cells (r=0.718, p=0.0008). Identical correlations were observed between baseline CD8+ T cell phenotype and CD8+ VIA at 12 mpi. Also, percentage of PD-1high CD8+ T cells negatively correlated with bulk and HIV-specific CD8+ TEM cells (r=−0.501, p=0.034 and r=−0.668, p=0.004, respectively). Conversely, positive correlations were observed with the proportion of bulk and HIV-specific CD8+ TE cells (r=-0.510, p=0.0308 and r=−0.564, p=0.022, respectively). Conclusions: A higher proportion of fully differentiated HIV-specific cells are related to the magnitude of CD8+ antiviral activity (rapidly able to exert effector functions) and to a higher PD-1 expression (related to T cell differentiation stage and activation status). This is the first report were a relation between CD8+ T cell memory differentiation hierarchy and antiviral function is reported during acute infection, providing information potentially useful for vaccine design.
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    Early Gag Immunodominance of the HIV-Specific T-Cell Response during Acute/Early Infection Is Associated with Higher CD8(+) T-Cell Antiviral Activity and Correlates with Preservation of the CD4(+) T-Cell Compartment
    (2013) Turk, Gabriela; Ghiglione, Yanina; Falivene, Juliana; Socias, Maria E.; Laufer, Natalia; Coloccini, Romina.; Rodriguez, Ana María; Ruiz, Maria; Pando, María; Giavedoni, Luis; Cahn, Pedro; Sued, Omar; Salomon, Horacio; Gherardi, María
    The important role of the CD8+ T-cell response on HIV control is well established. Moreover, the acute phase of infection represents a proper scenario to delineate the antiviral cellular functions that best correlate with control. Here, multiple functional aspects (specificity, ex vivo viral inhibitory activity [VIA] and polyfunctionality) of the HIV-specific CD8+ T-cell subset arising early after infection, and their association with disease progression markers, were examined. Blood samples from 44 subjects recruited within 6 months from infection (primary HIV infection [PHI] group), 16 chronically infected subjects, 11 elite controllers (EC), and 10 healthy donors were obtained. Results indicated that, although Nef dominated the anti-HIV response during acute/early infection, a higher proportion of early anti-Gag T cells correlated with delayed progression. Polyfunctional HIV-specific CD8+ T cells were detected at early time points but did not associate with virus control. Conversely, higher CD4+ T-cell set points were observed in PHI subjects with higher HIV-specific CD8+ T-cell VIA at baseline. Importantly, VIA levels correlated with the magnitude of the anti-Gag cellular response. The advantage of Gag-specific cells may result from their enhanced ability to mediate lysis of infected cells (evidenced by a higher capacity to degranulate and to mediate VIA) and to simultaneously produce IFN-γ. Finally, Gag immunodominance was associated with elevated plasma levels of interleukin 2 (IL-2) and macrophage inflammatory protein 1β (MIP-1β). All together, this study underscores the importance of CD8+ T-cell specificity in the improved control of disease progression, which was related to the capacity of Gag-specific cells to mediate both lytic and nonlytic antiviral mechanisms at early time points postinfection.
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    Early Skewed Distribution of Total and HIV-Specific CD8 T-Cell Memory Phenotypes during Primary HIV Infection Is Related to Reduced Antiviral Activity and Faster Disease Progression
    (2014-8) Ghiglione, Yanina; Falivene, Juliana; Ruiz, Maria; Laufer, Natalia; Socias, Maria E.; Cahn, Pedro; Giavedoni, Luis; Sued, Omar; Gherardi, María Magdalena; Salomon, Horacio; Turk, Gabriela
    The important role of the CD8+ T-cells on HIV control is well established. However, correlates of immune protection remain elusive. Although the importance of CD8+ T-cell specificity and functionality in virus control has been underscored, further unraveling the link between CD8+ T-cell differentiation and viral control is needed. Here, an immunophenotypic analysis (in terms of memory markers and Programmed cell death 1 (PD-1) expression) of the CD8+ T-cell subset found in primary HIV infection (PHI) was performed. The aim was to seek for associations with functional properties of the CD8+ T-cell subsets, viral control and subsequent disease progression. Also, results were compared with samples from Chronics and Elite Controllers. It was found that normal maturation of total and HIV-specific CD8+ T-cells into memory subsets is skewed in PHI, but not at the dramatic level observed in Chronics. Within the HIV-specific compartment, this alteration was evidenced by an accumulation of effector memory CD8+ T (TEM) cells over fully differentiated terminal effector CD8+ T (TTE) cells. Furthermore, higher proportions of total and HIV-specific CD8+ TEM cells and higher HIV-specific TEM/(TEM+TTE) ratio correlated with markers of faster progression. Analysis of PD-1 expression on total and HIV-specific CD8+ T-cells from PHI subjects revealed not only an association with disease progression but also with skewed memory CD8+ T-cell differentiation. Most notably, significant direct correlations were obtained between the functional capacity of CD8+ T-cells to inhibit viral replication in vitro with higher proportions of fully-differentiated HIV-specific CD8+ TTE cells, both at baseline and at 12 months post-infection. Thus, a relationship between preservation of CD8+ T-cell differentiation pathway and cell functionality was established. This report presents evidence concerning the link among CD8+ T-cell function, phenotype and virus control, hence supporting the instauration of early interventions to prevent irreversible immune damage.
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    Env-Specific IgA from Viremic HIV-Infected Subjects Compromises Antibody-Dependent Cellular Cytotoxicity
    (2016) Ruiz, Maria; Ghiglione, Yanina; Falivene, Juliana; Laufer, Natalia; Holgado, Maria Pia; Socias, Maria E.; Cahn, Pedro; Sued, Omar; Giavedoni, Luis; Salomon, Horacio; Gherardi, María Magdalena; Rodriguez, Ana María; Turk, Gabriela
    Elucidating the factors that modulate HIV-specific antibody-dependent cellular cytotoxicity (ADCC) will help in understanding its role in HIV immunity. The aim of this study was to determine whether IgA could modify the magnitude of ADCC in HIV infection, abrogating its protective role. Plasma samples from 20 HIV-positive (HIV(+)) subjects enrolled during primary HIV infection (PHI), 10 chronically infected subjects (chronic), and 7 elite controllers (EC) were used. ADCC was determined by using a fluorometric ADCC assay, before and after removal of plasma IgA. Data were analyzed by using nonparametric statistics. ADCC was documented in 80% of PHI enrollment samples and in 100% of PHI 12-month, chronic, and EC samples; it peaked after acute infection, reached a plateau in chronic infection, and decreased after initiation of antiretroviral treatment (ART). Significant associations between ADCC and disease progression were found only after removal of plasma IgA from 12-month PHI samples: the magnitude of ADCC not only increased after IgA removal but also correlated with CD4(+) T-cell preservation. This work provides evidence that gp120-specific IgA was capable of modifying ADCC responses during natural HIV infection for the first time and adds to similar evidence provided in other settings. Furthermore, it underscores the complexity of the ADCC phenomenon and will help in an understanding of its underlying mechanisms. Importance: Although the induction of ADCC-mediating antibodies in HIV-infected subjects has been extensively documented, the association of these antibodies with protection from disease progression is poorly understood. Here, we demonstrate that plasma IgA is a factor capable of modifying the magnitude of IgG-mediated ADCC in HIV infection, mitigating its beneficial effect. These results help in understanding why previous studies failed to demonstrate correlations between ADCC and disease progression, and they also contribute to the notion that an HIV vaccine should stimulate the production of ADCC-mediating IgG antibodies but not IgA.
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    Th17 and Th17/Treg ratio at early HIV infection associate with protective HIV-specific CD8+ T-cell responses and disease progression
    (2015) Falivene, Juliana; Ghiglione, Yanina; Laufer, Natalia; Socias, Maria E.; Holgado, Maria Pia; Ruiz, Maria; Maeto, Cynthia; Figueroa, Maria Ines; Giavedoni, Luis D.; Cahn, Pedro; Salomon, Horacio; Sued, Omar; Turk, Gabriela; Gherardi, María Magdalena
    The aim of this study was to analyze Th17 and Treg subsets and their correlation with anti-HIV T-cell responses and clinical parameters during (acute/early) primary HIV infection (PHI) and up to one year post-infection (p.i). Samples from 14 healthy donors (HDs), 40 PHI patients, 17 Chronics and 13 Elite controllers (ECs) were studied. The percentages of Th17 and Treg subsets were severely altered in Chronics, whereas all HIV-infected individuals (including ECs) showed Th17/Treg imbalance compared to HDs, in concordance with higher frequencies of activated CD8+ T-cells (HLA-DR+/CD38+). Better clinical status (higher CD4 counts, lower viral loads and activation) was associated with higher Th17 and lower Treg levels. We found positive correlations between Th17 at baseline and anti-HIV CD8+ T-cell functionality: viral inhibitory activity (VIA) and key polyfunctions (IFN-γ+/CD107A/B+) at both early and later times p.i, highlighting the prognostic value of Th17 cells to preserve an effective HIV T-cell immunity. Th17/Treg ratio and the IL-17 relative mean fluorescence intensity (rMFI of IL-17) were also positively correlated with VIA. Taken together, our results suggested a potential link between Th17 and Th17/Treg ratio with key HIV-specific CD8+ T-cell responses against the infection.