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Alterations in natural killer cell receptor profiles during HIV type 1 disease progression among chronically infected South African adults.

ABSTRACT: Recent studies suggest that innate immune responses by natural killer (NK) cells play a significant role in restricting human immunodeficiency virus type-1 (HIV-1) pathogenesis. Our aim was to characterize changes in NK cells associated with HIV-1 clade C disease progression. Here we used multiparametric flow cytometry (LSRII) to quantify phenotype and function of NK cells in a cross-sectional analysis of cryopreserved blood samples from a cohort of 41 chronically HIV-1-infected, treatment-naive adult South Africans. These individuals ranged in disease severity from early (CD4 count >500) to advanced HIV-1 disease (CD4 count <50). We found that the frequency of NK cells expressing KIR2DL1, an inhibitory receptor, and/or KIR2DS1, an activating receptor, tended to decrease with increasing HIV-1 viral load. We also discovered a significant increase (p < 0.05) in overall NK cell degranulation with disease progression. We found that acutely activated NK cells (CD69(pos)) were deficient in NKp46 expression ex vivo. In conclusion, we observed that with viremia and advanced HIV-1 disease, activated NK cells lack NKp46 expression, and KIR2DS1(pos) and/ or KIR2DL1(pos) NK cells are reduced in frequency. These findings suggest that modulation of receptor expression on NK cells may play a role in HIV-1 pathogenesis, and provide new insights on immunological changes in advanced HIV-1 disease.

SUBMITTER: Wong AH

PROVIDER: S-EPMC3111148 | biostudies-literature | 2010 Apr

REPOSITORIES: biostudies-literature

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Alterations in natural killer cell receptor profiles during HIV type 1 disease progression among chronically infected South African adults.

Wong Ambrose H W AH Williams Katie K Reddy Sharon S Wilson Douglas D Giddy Janet J Alter Galit G Ghebremichael Musie M Carrington Mary N MN Ndung'u Thumbi T Walker Bruce D BD Altfeld Marcus M Carr William H WH

AIDS research and human retroviruses 20100401 4

Recent studies suggest that innate immune responses by natural killer (NK) cells play a significant role in restricting human immunodeficiency virus type-1 (HIV-1) pathogenesis. Our aim was to characterize changes in NK cells associated with HIV-1 clade C disease progression. Here we used multiparametric flow cytometry (LSRII) to quantify phenotype and function of NK cells in a cross-sectional analysis of cryopreserved blood samples from a cohort of 41 chronically HIV-1-infected, treatment-naive ...[more]

PMID: 20380481

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Project description:Background: HIV-infected individuals have increased risk of developing obstructive lung disease (OLD). Studies from developed countries report high viral load, low CD4 counts, and anti-retroviral therapy (ART) to be associated with OLD; but these findings may not be generalizable to populations in resource-limited settings.Methods: We conducted a prospective cohort study of lung function in 730 HIV-infected black South African adults. Pre-bronchodilator spirometry was performed at enrollment and repeated annually for three years. Logistic regression models were used to identify factors associated with OLD, defined as FEV1/FVC<0.70, at enrollment. Excess annual declines in FEV1 and FVC were modelled as the product-term of follow-up time and exposures using random effects regression.Results: Median (IQR) age at enrollment was 36 (32-41) years, 85% were female and 30% ever-smoked with a median (IQR) exposure of 3 (1-6) pack-years. Median (IQR) CD4 count and viral load at enrollment were 372 (261-518) cells/mm3 and 2655 (91-13,548) copies/mL respectively. Overall, 25% were receiving ART at enrollment, 16% of whom reported at least 6 months of ART receipt. OLD was found in 35 (5%) at enrollment. Increasing age (aOR = 2.08 per 10-years [95%CI 1.22-3.57], p = 0.007), current smoking (aOR = 3.55 [95%CI 1.20-10.53], p = 0.02), and CRP (aOR = 1.01 per unit-increase [95%CI 1.00-1.03], p = 0.04) were significantly associated with OLD at enrollment; while increasing CD4 count (aOR = 1.02 per-100 cells/mm3 [95%CI 0.85-1.22], p = 0.82), viral load (aOR = 0.67 per log-increase [95%CI 0.43-1.10], p = 0.12) and receipt of ART (aOR = 0.57 [95%CI 0.18-1.75], p = 0.32) were not. The median (IQR) follow-up time was 18 (12-24) months. Participants with a history of tuberculosis (TB) had a 35 mL (95%CI 2-68, p = 0.03) and 57 mL (95%CI 19-96, p = 0.003) per year excess loss of FEV1 and FVC respectively.Conclusion: Prevalent OLD was associated with older age, current smoking and higher CRP levels, but not CD4 counts and ART, in HIV-infected South African adults. Better understanding of the long-term effects of TB, smoking and inflammation on lung function in HIV-infected populations is urgently needed.

Project description:Disease progression in HIV-1 infected children is faster than in adults. Less than 5% of the infected children maintain stable CD4 counts beyond 7 years of infection and are termed long-term nonprogressors (LTNPs). Delineating the host immune response in antiretroviral naïve (ART) and treated HIV-1 infected children at different disease stages will help in understanding the immunopathogenesis of the disease.A total of 79 asymptomatic, perinatally HIV-1 infected children (50 ART naïve and 29 ART treated) and 8 seronegative donors were recruited in this study. T- and B-cell activation PCR arrays were performed from the cDNA, using total RNA extracted from the peripheral blood mononuclear cells (PBMCs) of 14 HIV-1 infected children at different stages of the disease. The differentially expressed genes were identified. Quantitative RT-PCR was performed for the (interleukin-8) IL-8 gene and its transcriptional mediators, that is, SHP2, GRB2, and IL-8R (IL-8 receptor/CXCR1). Plasma levels of IL-8 were measured by flow cytometry.Gene array data revealed a higher expression of IL-8 in the ART naïve HIV-1 infected progressors and in ART nonresponders than LTNPs and ART responders, respectively. Quantitative RT-PCR analysis demonstrated a significant higher expression of IL-8 (P?<?0.001), its receptor CXCR1 (P?=?0.03) and the upstream signaling molecule SHP2 (P?=?0.04) in the progressors versus LTNPs. Plasma levels of IL-8 were significantly higher in progressors versus LTNPs (P?<?0.001), and ART nonresponders versus ART responders (P?<?0.001). A significant negative correlation of plasma levels of IL-8 with CD4 counts (cells/?L) was observed in HIV-1 infected ART naïve subjects (r?=?-0.488; P?<?0.001), while the IL-8 levels positively correlated with viral load in the ART treated children (r?=?0.5494; P?<?0.001). ART naïve progressors on follow up demonstrated a significant reduction in the mRNA expression (P?=?0.05) and plasma levels of IL-8 (P?=?0.05) post 6 months of ART initiation suggesting the beneficial role of ART therapy in reducing inflammation in infected children.Our data suggest that IL-8 may serve as a potential prognostic marker in adjunct with CD4 counts to monitor disease progression in the HIV-1 infected children and the efficacy of ART.

Project description:Siglec-9 is an MHC-independent inhibitory receptor expressed on a subset of natural killer (NK) cells. Siglec-9 restrains NK cytotoxicity by binding to sialoglycans (sialic acid-containing glycans) on target cells. Despite the importance of Siglec-9 interactions in tumor immune evasion, their role as an immune evasion mechanism during HIV infection has not been investigated. Using in vivo phenotypic analyses, we found that Siglec-9+ CD56dim NK cells, during HIV infection, exhibit an activated phenotype with higher expression of activating receptors and markers (NKp30, CD38, CD16, DNAM-1, perforin) and lower expression of the inhibitory receptor NKG2A, compared to Siglec-9- CD56dim NK cells. We also found that levels of Siglec-9+ CD56dim NK cells inversely correlate with viral load during viremic infection and CD4+ T cell-associated HIV DNA during suppressed infection. Using in vitro cytotoxicity assays, we confirmed that Siglec-9+ NK cells exhibit higher cytotoxicity towards HIV-infected cells compared to Siglec-9- NK cells. These data are consistent with the notion that Siglec-9+ NK cells are highly cytotoxic against HIV-infected cells. However, blocking Siglec-9 enhanced NK cells' ability to lyse HIV-infected cells, consistent with the known inhibitory function of the Siglec-9 molecule. Together, these data support a model in which the Siglec-9+ CD56dim NK subpopulation is highly cytotoxic against HIV-infected cells even whilst being restrained by the inhibitory effects of Siglec-9. To harness the cytotoxic capacity of the Siglec-9+ NK subpopulation, which is dampened by Siglec-9, we developed a proof-of-concept approach to selectively disrupt Siglec/sialoglycan interactions between NK and HIV-infected cells. We achieved this goal by conjugating Sialidase to several HIV broadly neutralizing antibodies. These conjugates selectively desialylated HIV-infected cells and enhanced NK cells' capacity to kill them. In summary, we identified a novel, glycan-based interaction that may contribute to HIV-infected cells' ability to evade NK immunosurveillance and developed an approach to break this interaction.

Dataset Information

Alterations in natural killer cell receptor profiles during HIV type 1 disease progression among chronically infected South African adults.

Publications

Alterations in natural killer cell receptor profiles during HIV type 1 disease progression among chronically infected South African adults.

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