The tolerogenic peptide hCDR1 immunomodulates cytokine and regulatory molecule gene expression in blood mononuclear cells of primary Sjogren's syndrome patients.

Primary Sjogren's syndrome (pSS) is an autoimmune disease characterized by lymphocytic infiltration of exocrine glands. We investigated whether the tolerogenic peptide, hCDR1, that ameliorates lupus manifestations would have beneficial effects on pSS as well. The in vitro effects of hCDR1 on gene expression of pro-inflammatory cytokines and regulatory molecules were tested in peripheral blood mononuclear cells (PBMC) of 16 pSS patients.

Induction and Measurement of Cytotoxic T Lymphocyte Activity.

Cytotoxic T cells (CTLs) are important immune effector cells in the adaptive immune response. It has been well documented that CTLs are important in host immune responses to viral and bacterial intracellular pathogens, tumors, and transplanted tissues. The properties of CTLs have been studied extensively in murine models, and their roles validated in the human setting.

Attenuation of pathogenic immune responses during infection with human and simian immunodeficiency virus (HIV/SIV) by the tetracycline derivative minocycline.

HIV immune pathogenesis is postulated to involve two major mechanisms: 1) chronic innate immune responses that drive T cell activation and apoptosis and 2) induction of immune regulators that suppress T cell function and proliferation. Both arms are elevated chronically in lymphoid tissues of non-natural hosts, which ultimately develop AIDS. However, these mechanisms are not elevated chronically in natural hosts of SIV infection that avert immune pathogenesis despite similarly high viral loads.

Transient increase of interferon-stimulated genes and no clinical benefit by chloroquine treatment during acute simian immunodeficiency virus infection of macaques.

Simian immunodeficiency virus (SIV) infection leads to AIDS in experimentally infected Rhesus macaques similarly to HIV-infected humans. In contrast, SIV infection of natural hosts is characterized by a down-regulation of innate acute responses to the virus within a few weeks of infection and results in limited pathology. Chloroquine (CQ) has been used in the treatment or prevention of malaria and has recently been shown to cause a decrease of immune activation and CD4 cell loss in HIV-infected individuals treated with antiretroviral therapy.

Fatal pancreatitis in simian immunodeficiency virus SIV(mac251)-infected macaques treated with 2',3'-dideoxyinosine and stavudine following cytotoxic-T-lymphocyte-associated antigen 4 and indoleamine 2,3-dioxygenase blockade.

Human immunodeficiency virus (HIV) infection is associated with immune activation, CD4⁺-T-cell loss, and a progressive decline of immune functions. Antiretroviral therapy (ART) only partially reverses HIV-associated immune dysfunction, suggesting that approaches that target immune activation and improve virus-specific immune responses may be needed. We performed a preclinical study in rhesus macaques infected with the pathogenic simian immunodeficiency virus SIV(mac251) and treated with ART.

Overactivation of plasmacytoid dendritic cells inhibits antiviral T-cell responses: a model for HIV immunopathogenesis.

A delicate balance between immunostimulatory and immunosuppressive signals mediated by dendritic cells (DCs) and other antigen-presenting cells (APCs) regulates the strength and efficacy of antiviral T-cell responses. HIV is a potent activator of plasmacytoid DCs (pDCs), and chronic pDC activation by HIV promotes the pathogenesis of AIDS. Cholesterol is pivotal in maintaining HIV envelope integrity and allowing HIV-cell interaction.

Alloantigen-based AIDS vaccine: revisiting a "rightfully" discarded promising strategy.

This report revisits the accidental discovery that protection against simian immunodeficiency virus (SIV) infection in the early successful experimental AIDS vaccine studies in Rhesus macaques was due to antibodies directed against human leukocyte antigens (HLAs). The inactivated virus vaccine approach was discarded because protection was due to the host's immune reaction against the HLA acquired by SIV from the human cell lines in which it was grown, rather than against antigenic determinants of SIV itself. Subsequent studies have revealed that immune recognition of HLA on uninfected leukocytes also induces other factors that inhibit infection by both SIV and the human immunodeficiency virus.

Historical perspective on HIV‐exposed seronegative individuals: has nature done the experiment for us?

Multiple and frequent exposure to the human immunodeficiency virus (HIV) does not necessarily result in HIV infection. Approximately 15% of HIV exposed seronegative individuals repeatedly resist infection, a phenomenon that has been observed in all investigated HIV‐exposed cohorts. This brief report provides a limited historic perspective of the discovery of these cohorts and outlines some of the immunologic and genetic parameters that are associated with resistance.

Elevated systemic levels of inflammatory cytokines in older women with persistent cervical human papillomavirus infection.

Background: Defects in lymphoproliferative responses to mitogens/antigens in women >45 years old with a persistent type-specific human papillomavirus (HPV) infection have been reported.

Methods: To determine whether these defects were associated with altered cytokine profiles, plasma and peripheral blood mononuclear cell (PBMC) culture supernatants from 50 cases (oversampled for their reduced lymphoproliferative ability) and 50 uninfected controls (oversampled for their robust lymphoproliferative ability) were examined for 24 cytokines using multiplexed bead-based immunoassays and ELISA.

Results: The following plasma cytokines were significantly increased in cases relative to controls (cases versus controls; median pg/mL): interleukin (IL)-6, 393.

TLR activation pathways in HIV-1-exposed seronegative individuals.

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).

Defective in vitro IL-2 production in lupus is an early but secondary event paralleling disease activity: evidence from the murine parent-into-F1 model supports staging of IL-2 defects in human lupus.

T cell defects are a well described feature of both human and murine lupus however their exact significance is unclear. Evidence from an induced model of lupus, the P --> F1 model of chronic lupus-like GVHD demonstrates that a secondary inducible T cell defect in in vitro IL-2 and CTL responses occurs early in the course of lupus-like disease and well in advance of clinical disease. Defective Th cell function was probed using a novel approach categorizing the response to two stimuli:1) the MHC self restricted response, termed self +X; and 2) the allogeneic response.

Antiretroviral activity of the aminothiol WR1065 against Human Immunodeficiency virus (HIV-1) in vitro and Simian Immunodeficiency virus (SIV) ex vivo.

Background: WR1065 is the free-thiol metabolite of the cytoprotective aminothiol amifostine, which is used clinically at very high doses to protect patients against toxicity induced by radiation and chemotherapy. In an earlier study we briefly reported that the aminothiol WR1065 also inhibits HIV-1 replication in phytohemagglutinin (PHA)-stimulated human T-cell blasts (TCBs) infected in culture for 2 hr before WR1065 exposure. In this study we expanded the original observations to define the dose-response curve for that inhibition, and address the question of additive effects for the combination of WR1065 plus Zidovudine (AZT).

WR1065 mitigates AZT-ddI-induced mutagenesis and inhibits viral replication.

The success of nucleoside reverse transcriptase inhibitors (NRTIs) in treating HIV-1 infection and reducing mother-to-child transmission of the virus during pregnancy is accompanied by evidence that NRTIs cause long-term health risks for cancer and mitochondrial disease. Thus, agents that mitigate toxicities of the current combination drug therapies are needed. Previous work had shown that the NRTI-drug pair zidovudine (AZT)-didanosine (ddI) was highly cytotoxic and mutagenic; thus, we conducted preliminary studies to investigate the ability of the active moiety of amifostine, WR1065, to protect against the deleterious effects of this NRTI-drug pair.

Combined effect of antiretroviral therapy and blockade of IDO in SIV-infected rhesus macaques.

Increased activity of IDO, which catalyzes the degradation of Trp into kynurenine (Kyn), is observed during HIV/SIV infection, and it may contribute to the persistence of HIV/SIV by suppressing antiviral T cell responses. We administered the IDO inhibitor 1-methyl-d-tryptophan (d-1mT) for 13 days to SIV-infected rhesus macaques receiving antiretroviral therapy (ART). d-1mT treatment increased the plasma levels of Trp, without reducing the levels of Kyn, suggesting only a partial effect on IDO enzymatic activity.

HAART reduces death ligand but not death receptors in lymphoid tissue of HIV-infected patients and simian immunodeficiency virus-infected macaques.

Objective: To determine how antiretroviral therapy (ART) or HAART affects the expression of apoptotic ligands and their death receptors in the blood and lymphoid tissues of HIV-infected patients and simian immunodeficiency virus-infected macaques.

Methods: We analyzed the mRNA expression of death molecules [tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and FasL] and their receptors (DR5 and Fas) in blood and tonsils from HIV-infected patients (HIV positive), HIV-infected patients receiving HAART and HIV-uninfected (HIV negative) donors in a cross-sectional study. We comparatively analyzed mRNA expression of TRAIL and DR5 in blood and lymph nodes collected longitudinally from simian immunodeficiency virus-infected macaques before and after ART.

HIV-induced type I interferon and tryptophan catabolism drive T cell dysfunction despite phenotypic activation.

Infection by the human immunodeficiency virus (HIV) is characterized by functional impairment and chronic activation of T lymphocytes, the causes of which are largely unexplained. We cultured peripheral blood mononuclear cells (PBMC) from HIV-uninfected donors in the presence or absence of HIV. HIV exposure increased expression of the activation markers CD69 and CD38 on CD4 and CD8 T cells.

Fetal-maternal HLA-A and -B discordance is associated with placental RNase expression and anti-HIV-1 activity.

The incidence of maternal-to-fetal human immunodeficiency virus type 1 (HIV-1) transmission is 25-30% in absence of antiretroviral therapy, and is inversely associated with Human leukocyte antigens (HLA) class-I discordance. Based on our earlier report that mixed lymphocyte reactions (MLR) induce a ribonuclease (RNase) that inhibits HIV-1 replication, we proposed that maternal-fetal alloantigen stimulation activates factors that protect the fetus against vertically-transmitted infections. We investigate here whether the degree of mother-infant HLA discordance associates with the ability to produce anti-HIV-1 alloantigen-stimulated factor (ASF), and affects placental RNases.

PDL-1 upregulation on monocytes and T cells by HIV via type I interferon: restricted expression of type I interferon receptor by CCR5-expressing leukocytes.

The programmed death (PD)-1 interacts with its ligand (PDL-1) delivering a negative signal to T cells. During human immunodeficiency virus (HIV)-1 infection PD-1 and PDL-1 expressions are increased. Here we show that monocytes and CCR5(+) T cells of HIV-uninfected donors upregulated PDL-1 upon in vitro exposure to HIV.

Differential effect of type I and type II interferons on neopterin production and amino acid metabolism in human astrocyte-derived cells.

Intrathecal production of neopterin, a pteridine produced by interferon (IFN)-gamma-stimulated monocyte-derived macrophages, is associated with neurological disorders and infections. We investigated whether IFN-alpha/beta, IFN-gamma, or human immunodeficiency virus (HIV) induce neopterin production by human astroglioma cells. IFN-alpha/beta and IFN-gamma, but not HIV, induced neopterin.

Induction and measurement of cytotoxic T lymphocyte activity.

Cytotoxic T lymphocytes (CTL) kill target cells on the basis of cell-surface antigen recognition and are important in the host response to tumors, transplants, and viruses. This unit presents several protocols for generating and measuring CTL activity. The first describes generating CTL against some of the most commonly used target antigens.

Immune activation driven by CTLA-4 blockade augments viral replication at mucosal sites in simian immunodeficiency virus infection.

The importance of chronic immune activation in progression to AIDS has been inferred by correlative studies in HIV-infected individuals and in nonhuman primate models of SIV infection. Using the SIV(mac251) macaque model, we directly address the impact of immune activation by inhibiting CTLA-4, an immunoregulatory molecule expressed on activated T cells and a subset of regulatory T cells. We found that CTLA-4 blockade significantly increased T cell activation and viral replication in primary SIV(mac251) infection, particularly at mucosal sites, and increased IDO expression and activity.

HIV turns plasmacytoid dendritic cells (pDC) into TRAIL-expressing killer pDC and down-regulates HIV coreceptors by Toll-like receptor 7-induced IFN-alpha.

Plasmacytoid dendritic cells (pDC) are key players in viral immunity and produce IFN-alpha after HIV-1 exposure, which in turn regulates TNF-related apoptosis-inducing ligand (TRAIL) expression by CD4(+) T cells. We show here that infectious and noninfectious HIV-1 virions induce activation of pDC into TRAIL-expressing IFN-producing killer pDC (IKpDC). IKpDC expressed high levels of activation markers (HLA-DR, CD80, CD83, and CD86) and the migration marker CCR7.