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Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cytotoxic T lymphocytes (CTLs) play an essential role in the control of viral replication during human immunodeficiency virus (HIV) infection. However, the efficacy of the CTL response varies between individuals. We tested the hypothesis that genetic polymorphisms in the lytic effector molecule perforin could influence the progression of HIV infection. The perforin gene was screened for single nucleotide polymorphisms (SNPs) by denaturing high-performance liquid chromatography (dHPLC). Correlations were sought between perforin genotype, perforin expression and lytic function of CD8+ T lymphocytes from HIV-positive patients. Association of perforin genotype with disease progression was investigated in 426 seroconverters enrolled in the French SEROCO cohort. AIDS-free survival curves were constructed using the Kaplan-Meier method and compared using the log-rank test. Three SNPs were found in the proximal promoter region of the perforin gene: 63G (allelic frequency 0.029), 112G (allelic frequency 0.071) and 1012T (allelic frequency 0.070). The presence of the 1012T genotype correlated with fewer perforin+ cells among circulating CD8+ CTL. However, CTL lines from HIV(-positive) individuals heterozygous for the perforin 1012T SNP displayed normal lysis of target cells, and within the SEROCO cohort, patients heterozygous for the 1012T SNP showed normal disease progression. However, 1012T/T homozygotes showed a tendency towards slower disease progression (P = 0.08). In conclusion, polymorphism in the perforin gene is limited, and although the 1012T genotype appears to influence perforin expression, it was not conclusively associated with disease progression in HIV infection.
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PMID:Polymorphism in the proximal promoter region of the perforin gene and its impact on the course of HIV infection. 1661 Dec 50

Affordable therapeutic strategies that induce sustained control of human immunodeficiency virus type 1 (HIV-1) replication and are tailored to the developing world are urgently needed. Since CD8(+) and CD4(+) T cells are crucial to HIV-1 control, stimulation of potent cellular responses by therapeutic vaccination might be exploited to reduce antiretroviral drug exposure. However, therapeutic vaccines tested to date have shown modest immunogenicity. In this study, we performed a comprehensive analysis of the changes in virus-specific CD8(+) and CD4(+) T-cell responses occurring after vaccination of 16 HIV-1-infected individuals with a recombinant modified vaccinia virus Ankara-vectored vaccine expressing the consensus HIV-1 clade A Gag p24/p17 sequences and multiple CD8(+) T-cell epitopes during highly active antiretroviral therapy. We observed significant amplification and broadening of CD8(+) and CD4(+) gamma interferon responses to vaccine-derived epitopes in the vaccinees, without rebound viremia, but not in two unvaccinated controls followed simultaneously. Vaccine-driven CD8(+) T-cell expansions were also detected by tetramer reactivity, predominantly in the CD45RA(-) CCR7(+) or CD45RA(-) CCR7(-) compartments, and persisted for at least 1 year. Expansion was associated with a marked but transient up-regulation of CD38 and perforin within days of vaccination. Gag-specific CD8(+) and CD4(+) T-cell proliferation also increased postvaccination. These data suggest that immunization with MVA.HIVA is a feasible strategy to enhance potentially protective T-cell responses in individuals with chronic HIV-1 infection.
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PMID:Expansion and diversification of virus-specific T cells following immunization of human immunodeficiency virus type 1 (HIV-1)-infected individuals with a recombinant modified vaccinia virus Ankara/HIV-1 Gag vaccine. 1664 Dec 64

Simian immunodeficiency virus (SIV)-infection in macaques provides an important animal model for human immunodeficiency virus-1 (HIV-1) infection. The involvement of perforin (PFN), released by cytotoxic cells to mediate killing of virus-infected cells, has been difficult to assess in this experimental model due to a lack of reagents. We therefore evaluated monoclonal antibodies (mAbs) Pf-80, Pf-164 and Pf-344, previously raised against human PFN, for cross-reactivity with macaque PFN. Mabs Pf-164 and Pf-344 reacted with intracellular PFN in peripheral blood mononuclear cells (PBMC) from cynomolgus and rhesus macaques by flow cytometry and stained PFN in rhesus lymphoid tissue by immunohistochemistry (IHC). Moreover, PFN capture enzyme-linked immunosorbent (ELISA) and enzyme-linked immunospot (ELISpot) assays utilizing mAbs Pf-164/Pf-80 for capture and mAb Pf-344 for detection were used to quantify PFN release by mitogen-stimulated cynomolgus and rhesus PBMC. The PFN ELISpot was further used to quantify antigen-specific CD8+ T cells by ex vivo stimulation of PBMC from cynomolgus macaques immunized against SIV/HIV-1. These macaque PFN-reactive mAbs and immunoassays will be valuable new tools for investigation of cytotoxic T lymphocyte (CTL) responses in non-human primate models of infectious diseases as well as for vaccine development.
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PMID:Detection of macaque perforin expression and release by flow cytometry, immunohistochemistry, ELISA, and ELISpot. 1664 80

Cytotoxic lymphocytes are critical in the control of HIV replication, it has been shown that perforin is the key effector of killing machinery for CTLs and NK cells, so we investigated the circulating levels of perforin in CD8+ T cells and NK cells by flow cytometry intracellular stain in Chinese HIV infected individuals, its association with disease progression was analyzed. Our results showed that NK cells express perforin more efficiently than CD8+ T cells, CD8+ T cells expressed perforin higher than that of healthy controls, but NK cells expressed lower perforin than that of healthy controls, both were not correlated with disease progression. but significantly associated with their numbers, anti-retrovirus therapy had no evident effects on peforin expression in CD8+ T cells, but enhanced perfrin expression in NK cells, perforin expression in CD8+ T cells and CD16+ NK cells correlate with CD4+ T cell counts significantly in HAART-treated group. Therefore, different mechanisms may be involved in regulating peripheral perforin expression in different cell types.
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PMID:Differential expression of perforin in cytotoxic lymphocyte in HIV/AIDS patients of China. 1677 Jul

Natural killer (NK) cells are critical for the first-line defense in infection. Treated viremic HIV-1 infection is associated with the expansion of an anergic subset of CD3-CD56-CD16+ NK cells unable to respond to stimulation with MHC-devoid target cells or with mitogens. These CD3-CD56-CD16+ NK cells expressed SHIP-1 and had significantly reduced perforin levels. This observation suggests a mechanism for the reduced functional activity of CD3-CD56-CD16+ NK cells in chronic HIV-1 infection.
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PMID:Low perforin and elevated SHIP-1 expression is associated with functional anergy of natural killer cells in chronic HIV-1 infection. 1684 10

A 17-year-old girl previously in good health presented with a 2-month history of recurrent, high-grade fever; general fatigue; anorexia; a 10-kg weight loss; and multiple, painful, reddish skin lesions on the lower abdomen. Some lesions were ulcerated, with an oily yellowish brown discharge. A systemic review was unremarkable other than bleeding from the nose. Her medical and family histories were unremarkable. On examination, the patient was pale, jaundiced, and febrile (temperature of 39 degrees C). She had enlarged lymph nodes in the axillary and inguinal areas. There was moderate hepatosplenomegaly. Local skin examination revealed multiple erythematous, tender, and firm subcutaneous nodules of variable size (1-2 cm) on the lower abdomen. Some nodules were ulcerated, with oily yellowish brown discharge and overlying ecchymosis (Figures 1 and 2). Mucous membranes were free of lesions. Laboratory investigations showed pancytopenia, an elevated erythrocyte sedimentation rate (>80 mm/h), normal renal function tests, abnormal hepatic function tests (alanine aminotransferase 172 U/L, aspartate aminotransferase 229 U/L, alkaline phosphatase 725 U/L, and total bilirubin 100 mmol/L [normal range 0-18 mmol/L]), conjugated bilirubin 45 mmol/L (normal range 0-5 mmol/L), and high triglycerides 855 mg/dL (normal range 20-200 mg/dL). Prolonged prothrombin time, 26 seconds (normal range 13-16 seconds); prolonged activated partial thromboplastin time, 61 seconds (normal range 26-38 seconds); positive disseminated intravascular coagulation studies evidenced by low fibrinogen, 74 mg/dL (normal range 160-350 mg/dL); and positive fibrinogen degradation products were also noted. Throat, midstream urine, and blood culture results were negative. Serologic tests for syphilis, HIV, and hepatitis B and C viruses were negative. Epstein-Barr virus and cytomegalovirus serologic values revealed evidence of past infection. Tuberculin and Coombs tests were negative. The alpha1-antitrypsin level was normal. Antinuclear and anti-smith antibodies, rheumatoid factor, and cryoglobulins were negative. CT showed enlarged lymph nodes in the axillary and inguinal areas, bilateral small pleural effusion, moderate hepatosplenomegaly, severe fatty infiltration of the liver, and thickening of lower abdominal subcutaneous tissue. A liver biopsy showed steatohepatitis. Bone marrow aspirate and trephine were normal. A deep punch biopsy of a nodule from the right lower abdomen revealed lobular panniculitis with atypical lymphocytes and large macrophages with cytophagocytosis ("beanbag" cells) (Figures 3 and 4). Immunohistochemistry showed that these atypical cells were positive for CD3, CD8, granzyme B, and perforin, and negative for CD56. T-cell gene rearrangement studies on skin lesions revealed a monoclonal T-cell receptor (gamma-chain) gene rearrangement, supporting the diagnosis of subcutaneous panniculitis-like T-cell lymphoma. On presentation, the initial treatment included 6 U of fresh frozen plasma, 2 U of packed red blood cells, and 2 g IV fibrinogen for 3 consecutive days. The patient was started on prednisolone 60 mg orally once daily and cyclosporine A 5 mg/kg/d orally in two divided doses. The fever and other systemic symptoms and skin lesions resolved within 2 weeks after the treatment. The prednisolone dose was tapered gradually, and a maintenance dose of cyclosporine A was continued. The patient's condition remained in remission at 12-month follow-up; there was no evidence of clinical relapse.
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PMID:Subcutaneous panniculitis-like T-cell lymphoma with hemophagocytic syndrome successfully treated with cyclosporin A. 1685 14

Regulatory T (Treg) cells accumulate in the lymphoid tissues of human immunodeficiency virus (HIV)-infected individuals, contributing to the inability of the immune system to control virus replication. We investigate here Treg-cell numbers and functional markers (FOXP3, CTLA-4, IDO, and TGF-beta1) in lymphoid tissues from untreated infected hosts with progressive or nonprogressive disease (HIV-infected humans and simian immunodeficiency virus [SIV]-infected macaques). We found that increased numbers of FOXP3(+) T cells as well as increased expression of Treg-cell-associated functional markers were detected only during progressive disease. Such increases were not correlated with immune activation. Of importance, a high-perforin/FOXP3 ratio was associated with nonprogressive disease, suggesting that the immune control of virus replication represents a balance between cell-mediated immune responses and Treg-cell-mediated counter regulation of such responses. Furthermore, using an in vitro model of Treg-cell-HIV interactions, we showed that exposure of Treg cells to HIV selectively promoted their survival via a CD4-gp120-dependent pathway, thus providing an underlying mechanism for the accumulation of Treg cells in infected hosts with active viral replication. Considered together, our findings imply that therapeutic manipulation of Treg-cell number and/or function could improve immune control of HIV infection.
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PMID:HIV-1-driven regulatory T-cell accumulation in lymphoid tissues is associated with disease progression in HIV/AIDS. 1690 47

We have previously shown decreased expression of the interleukin (IL)-7 receptor alpha-chain (CD127) on CD8 T-cells in HIV-infected patients and an apparent recovery of this receptor in those receiving antiretroviral therapy with sustained viral suppression. Here, we demonstrate that the HIV Tat protein specifically downregulates cell surface expression of CD127 on human CD8 T-cells in a dose- and time-dependent manner. The effects of Tat on CD127 expression could be blocked with anti-Tat monoclonal antibodies or by preincubating Tat with heparin. Tat had no effect on the expression of other cell surface proteins examined, including CD132, or on cell viability over 72 hours. Further, CD127 expression was not altered by other HIV proteins, including gp160 or Nef. Preincubation of purified CD8 T-cells with Tat protein inhibited CD8 T-cell proliferation and perforin synthesis after stimulation with IL-7. Because IL-7 signaling is essential for optimal CD8 T-cell proliferation and function, the downregulation of CD127 and apparent inhibition of cytotoxic activity by Tat may play an important role in HIV-induced immune dysregulation and impaired cell-mediated immunity.
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PMID:Interleukin-7 receptor expression on CD8 T-cells is downregulated by the HIV Tat protein. 1696 44

CD8+ CD57+ T lymphocytes, present at low levels in the peripheral blood of healthy individuals expand during HIV infection and remain elevated during chronic infection. Their role in the immune response remains unclear. We performed a large-scale gene array analysis (3158 genes) to characterize them and, interestingly, found no distinction in the transcriptional profiles of CD8+ CD57+ T lymphocytes from HIV-infected and uninfected subjects. In both groups, these cells showed specificity for multiple Ags and produced large amounts of IFN-gamma and TNF-alpha. The transcriptional profiles of CD8+ CD57+ and CD8+ CD57- cells, however, differed substantially. We propose that CD8+ CD57+ cells were Ag-driven effector cells with very high cytotoxic effector potential including perforin, granzymes, and granulysin, regardless of HIV status. At both the messenger and protein levels, they expressed more adhesion molecules and fewer chemokine receptors (CCR7 and CXCR4) than CD8+ CD57- cells but expressed preferentially CX3CR1. The lower expression level of genes involved in cell cycle regulation showed limited proliferation capacities of CD8+ CD57+ even in response to TCR and IL-2, IL-7, and IL-15 stimulation. CD8+ CD57+ T cells from both HIV and uninfected subjects maintain effective cytotoxic potentials but are destined to migrate to nonlymphoid tissues without further cycling.
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PMID:High cytotoxic and specific migratory potencies of senescent CD8+ CD57+ cells in HIV-infected and uninfected individuals. 1701 99

An urgent need exists to devise strategies to augment antiviral immune responses in patients with HIV who are virologically well controlled and immunologically stable on highly active antiretroviral therapy (HAART). The objective of this study was to compare the immunomodulatory effects of the cytokines interleukin (IL)-21 with IL-15 on CD8 T cells in patients with HIV RNA of less than 50 copies/mL and CD4 counts greater than 200 cells/mm.(3) Patient CD8 T cells displayed skewed maturation and decreased perforin expression compared with healthy controls. Culture of freshly isolated patient peripheral-blood mononuclear cells (PBMCs) for 5 hours to 5 days with IL-21 resulted in up-regulation of perforin in CD8 T cells, including memory and effector subsets and virus-specific T cells. IL-21 did not induce T-cell activation or proliferation, nor did it augment T-cell receptor (TCR)-induced degranulation. Treatment of patient PBMCs with IL-15 resulted in induction of perforin in association with lymphocyte proliferation and augmentation of TCR-induced degranulation. Patient CD8 T cells were more responsive to cytokine effects than the cells of healthy volunteers. We conclude that CD8 T cells of patients with HIV can be modulated by IL-21 to increase perforin expression without undergoing overt cellular activation. IL-21 could potentially be useful for its perforin-enhancing properties in anti-HIV immunotherapy.
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PMID:Differential effects of IL-21 and IL-15 on perforin expression, lysosomal degranulation, and proliferation in CD8 T cells of patients with human immunodeficiency virus-1 (HIV). 1719 92


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