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  • The American Association of Immunologists  (3)
  • 2010-2014  (3)
  • 1
    Online Resource
    Online Resource
    TLR Activation Pathways in HIV-1–Exposed Seronegative Individuals
    The American Association of Immunologists ; 2010
    In:  The Journal of Immunology Vol. 184, No. 5 ( 2010-03-01), p. 2710-2717
    Details
    In: The Journal of Immunology, The American Association of Immunologists, Vol. 184, No. 5 ( 2010-03-01), p. 2710-2717
    Abstract: TLRs trigger innate immunity that recognizes conserved motifs of invading pathogens, resulting in cellular activation and release of inflammatory factors. The influence of TLR activation on resistance to HIV-1 infection has not been investigated in HIV-1 exposed seronegative (ESN) individuals. PBMCs isolated from heterosexually ESN individuals were stimulated with agonists specific for TLR3 (poly I:C), TLR4 (LPS), TLR7 (imiquimod), and TLR7/8 (ssRNA40). We evaluated expression of factors involved in TLR signaling cascades, production of downstream effector immune mediators, and TLR-expression in CD4+ and CD14+ cells. Results were compared with those obtained in healthy controls (HCs). ESN individuals showed: 1) comparable percentages of CD14+/TLR4+ and CD4+/TLR8+ CD14+/TLR8+ cells; 2) higher responsiveness to poly I:C, LPS, imiquimod, and ssRNA40 stimulation, associated with significantly increased production of IL-1β, IL-6, TNF-α, and CCL3; 3) augmented expression of mRNA specific for other targets (CCL2, CSF3, CSF2, IL-1α, IL-8, IL-10, IL-12, cyclooxygenase 2) demonstrated by broader TLRs pathway expression analyses; and 4) increased MyD88/MyD88s(short) ratio, mainly following TLR7/8 stimulation. We also compared TLR–agonist-stimulated cytokine/chemokine production in CD14+ PBMCs and observed decreased IFN-β production in ESN individuals compared with HCs upon TLR7/8-agonist stimulation. These data suggest that TLR stimulation in ESN individuals results in a more robust release of immunologic factors that can influence the induction of stronger adaptive antiviral immune responses and might represent a virus-exposure–induced innate immune protective phenotype against HIV-1.
    Type of Medium: Online Resource
    ISSN: 0022-1767 , 1550-6606
    URL: Article
    DOI: 10.4049/jimmunol.0902463
    RVK:
    XA 54100
    RVK:
    XA 10000
    Language: English
    Publisher: The American Association of Immunologists
    Publication Date: 2010
    detail.hit.zdb_id: 1475085-5
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  • 2
    Online Resource
    Online Resource
    A Common Polymorphism in TLR3 Confers Natural Resistance to HIV-1 Infection
    The American Association of Immunologists ; 2012
    In:  The Journal of Immunology Vol. 188, No. 2 ( 2012-01-15), p. 818-823
    Details
    In: The Journal of Immunology, The American Association of Immunologists, Vol. 188, No. 2 ( 2012-01-15), p. 818-823
    Abstract: TLR3 recognizes dsRNA and activates antiviral immune responses through the production of inflammatory cytokines and type I IFNs. Genetic association studies have provided evidence concerning the role of a polymorphism in TLR3 (rs3775291, Leu412Phe) in viral infection susceptibility. We genotyped rs3775291 in a population of Spanish HIV-1–exposed seronegative (HESN) individuals who remain HIV seronegative despite repeated exposure through i.v. injection drug use (IDU-HESN individuals) as witnessed by their hepatitis C virus seropositivity. The frequency of individuals carrying at least one 412Phe allele was significantly higher in IDU-HESN individuals compared with that of a matched control sample (odds ratio for a dominant model = 1.87; 95% confidence interval, 1.06–3.34; p = 0.023). To replicate this finding, we analyzed a cohort of Italian, sexually HESN individuals. Similar results were obtained: the frequency of individuals carrying at least one 412Phe allele was significantly higher compared with that of a matched control sample (odds ratio, 1.79; 95% confidence interval, 1.05–3.08; p = 0.029). In vitro infection assays showed that in PBMCs carrying the 412Phe allele, HIV-1Ba-L replication was significantly reduced (p = 0.025) compared with that of Leu/Leu homozygous samples and was associated with a higher expression of factors suggestive of a state of immune activation (IL-6, CCL3, CD69). Similarly, stimulation of PBMCs with a TLR3 agonist indicated that the presence of the 412Phe allele results in a significantly increased expression of CD69 and higher production of proinflammatory cytokines including IL-6 and CCL3. The data of this study indicate that a common TLR3 allele confers immunologically mediated protection from HIV-1 and suggest the potential use of TLR3 triggering in HIV-1 immunotherapy.
    Type of Medium: Online Resource
    ISSN: 0022-1767 , 1550-6606
    URL: Article
    DOI: 10.4049/jimmunol.1102179
    RVK:
    XA 54100
    RVK:
    XA 10000
    Language: English
    Publisher: The American Association of Immunologists
    Publication Date: 2012
    detail.hit.zdb_id: 1475085-5
    Location Call Number Limitation Availability
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    Online Resource
  • 3
    Online Resource
    Online Resource
    IL-21 Promotes Skin Recruitment of CD4+ Cells and Drives IFN-γ–Dependent Epidermal Hyperplasia
    The American Association of Immunologists ; 2011
    In:  The Journal of Immunology Vol. 186, No. 9 ( 2011-05-01), p. 5435-5442
    Details
    In: The Journal of Immunology, The American Association of Immunologists, Vol. 186, No. 9 ( 2011-05-01), p. 5435-5442
    Abstract: Psoriasis is a chronic inflammatory disorder of the skin characterized by epidermal hyperplasia and infiltration of leukocytes into the dermis and epidermis. T cell-derived cytokines, such as IFN-γ and IL-17A, play a major role in the psoriasis-associated epidermal hyperplasia, even though factors/mechanisms that regulate the production of these cytokines are not fully understood. We have recently shown that IL-21 is synthesized in excess in psoriatic skin lesions and causes epidermal hyperplasia when injected intradermally in mice. Moreover, in the human psoriasis SCID mouse model, neutralization of IL-21 reduces both skin thickening and expression of inflammatory molecules, thus supporting the pathogenic role of IL-21 in psoriasis. However, the basic mechanism by which IL-21 promotes skin pathology remains unknown. In this study, we show that CD4+ cells accumulate early in the dermis of IL-21–treated mice and mediate the development of epidermal hyperplasia. Indeed, IL-21 fails to induce skin damage in RAG1-deficient mice and CD4+ cell-depleted wild-type mice. The majority of CD4+ cells infiltrating the dermis of IL-21–treated mice express IFN-γ and, to a lesser extent, IL-17A. Studies in cytokine knockout mice show that IFN-γ, but not IL-17A, is necessary for IL-21–induced epidermal hyperplasia. Finally, we demonstrate that IFN-γ–producing CD4+ cells infiltrating the human psoriatic plaque express IL-21R, and abrogation of IL-21 signals reduces IFN-γ expression in cultures of psoriatic CD4+ cells. Data indicate that IL-21 induces an IFN-γ–dependent pathogenic response in vivo, thus contributing to elucidate a mechanism by which IL-21 sustains skin-damaging inflammation.
    Type of Medium: Online Resource
    ISSN: 0022-1767 , 1550-6606
    URL: Article
    DOI: 10.4049/jimmunol.1003326
    RVK:
    XA 54100
    RVK:
    XA 10000
    Language: English
    Publisher: The American Association of Immunologists
    Publication Date: 2011
    detail.hit.zdb_id: 1475085-5
    Location Call Number Limitation Availability
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