Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UMLS:C0021051 (immunodeficiency)
71,517 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Macrophages are early targets of human immunodeficiency virus type 1 (HIV-1) infection and serve as potential reservoirs for long-term infection. Through inflammatory mediators and direct cell contact, infected macrophages interact with neighboring cell populations, such as the endothelium, which create a microenvironment favorable for HIV-1 replication. We hypothesize that the transcriptional activator C/EBPbeta is critical for macrophages to respond to endothelial cell-derived signals. We show that endothelial cells significantly enhance C/EBPbeta binding activity and HIV-1 replication in macrophages. This increase in HIV-1 transcription is due to cell-cell contact as well as the production of soluble factors, mediated in part by ICAM-1 and interleukin 6, respectively. Furthermore, C/EBP factors are necessary for endothelial cell-dependent activation of HIV-1 transcription in macrophages, and HIV-1 induction can be inhibited by a C/EBP dominant-negative protein. In addition, C/EBP binding sites are necessary for efficient LTR activity and HIV-1 replication in the presence of endothelial cells. Taken together, these results indicate that endothelial cells, through the activation of C/EBPbeta, provide a microenvironment that supports HIV-1 replication in monocytes/macrophages.
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PMID:Endothelial cells enhance human immunodeficiency virus type 1 replication in macrophages through a C/EBP-dependent mechanism. 1155 3

Cellular interleukin 6 (IL-6) is an important growth factor for Kaposi sarcoma- associated herpesvirus (KSHV)-associated neoplasms, which include human immunodeficiency virus (HIV)-related and -unrelated cases of Kaposi sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman disease (MCD). Increased IL-6 levels are found in tissues affected with these diseases, and KSHV exists in a latent state in the majority of virally infected cells. In addition, acute infection with KSHV up-regulates IL-6 expression in endothelial cells. Thus, the hypothesis was considered that a latent KSHV gene product up-regulates IL-6 expression. To evaluate this hypothesis, the KSHV latency-associated nuclear antigen (LANA) was expressed in human embryonal kidney 293 cells and a bone marrow stromal cell line. LANA up-regulates IL-6 expression by inducing transcription from the IL-6 promoter, and the AP1 response element within the IL-6 promoter is necessary for and mediates IL-6 up-regulation by LANA. Thus, LANA may play a key pathophysiologic role in KSHV-associated neoplasms by functioning to up-regulate expression of IL-6.
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PMID:The Kaposi sarcoma-associated herpesvirus (KSHV) induces cellular interleukin 6 expression: role of the KSHV latency-associated nuclear antigen and the AP1 response element. 1178 Dec 50

Activating cells of the immune system may stimulate human immunodeficiency virus type 1 (HIV-1) replication and contribute to select pathogenic variants in vivo. Here, we examined the possible effect of a major pathway of immune activation, CD40 interaction with its ligand (CD40L), on the susceptibility of monocyte-derived macrophages (MDMs) to various HIV-1 strains. Stimulation of MDMs with CD40L led to reduced replication of R5 HIV-1(Ba-L), whereas this strongly enhanced the replication of X4 HIV-1(Lai) as well as of X4 primary isolates, and this was associated with strong cytopathic effects. The replication of X4 strains was inhibited by stromal cell-derived factor 1, an indication of the restricted usage of CXCR4 as virus coreceptor in this case. CD40L induced the activation of mitogen-activated protein kinases ERK1/ERK2 and stimulated MDMs to secrete RANTES (regulated on activation, normal T cell expressed and secreted), macrophage inflammatory protein 1alpha (MIP-1alpha), MIP-1beta, interleukin 6 (IL-6), IL-1beta, and tumor necrosis factor alpha. From this data, it may be hypothesized that activated macrophages represent a favorable environment for the replication of classically T lymphocyte-tropic X4 variants and, thus, may contribute significantly to the selection of such variants at late stages of clinical HIV-1 infection.
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PMID:CD40-activated macrophages become highly susceptible to X4 strains of human immunodeficiency virus type 1. 1183 43

Multicentric Castleman disease (MCD) is a distinct type of lymphoproliferative disorder associated with inflammatory symptoms and interleukin 6 (IL-6) dysregulation. In the context of human immunodeficiency virus (HIV) infection, MCD is associated with Kaposi sarcoma-associated herpesvirus, also called human herpesvirus type 8 (KSHV/HHV8). Within a prospective cohort study on 60 HIV-infected patients with MCD, and a median follow-up period of 20 months, 14 patients developed KSHV/HHV8-associated non-Hodgkin lymphoma (NHL): 3 "classic" KSHV/HHV8(+) Epstein-Barr virus-positive (EBV(+)) primary effusion lymphoma (PEL), 5 KSHV/HHV8(+) EBV(-) visceral large cell NHL with a PEL-like phenotype, and 6 plasmablastic lymphoma/leukemia (3/3 KSHV/HHV8(+) EBV(-)). The NHL incidence observed in this cohort study (101/1000 patient-years) is about 15-fold what is expected in the general HIV(+) population. MCD-associated KSHV/HHV8(+) NHL fell into 2 groups, suggesting different pathogenesis. The plasmablastic NHL likely represents the expansion of plasmablastic microlymphoma from the MCD lesion and progression toward aggressive NHL. In contrast, the PEL and PEL-like NHL may implicate a different original infected cell whose growth is promoted by the cytokine-rich environment of the MCD lesions.
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PMID:High incidence of Kaposi sarcoma-associated herpesvirus-related non-Hodgkin lymphoma in patients with HIV infection and multicentric Castleman disease. 1189 64

Treatment of patients with human immunodeficiency virus (HIV) protease inhibitors such as ritonavir can result in increases in CD4(+) T-cell counts that are independent of a reduction in HIV-1 viral load. This lack of correlation between the 2 has led to the identification of additional effects of ritonavir that potentially alter HIV disease pathogenesis. Our previous studies indicated that ritonavir directly affects immune cell activation, proliferation, and susceptibility to apoptosis. We show here that ritonavir inhibited the activation and proliferation of primary endothelial cells and decreased the production of tumor necrosis factor alpha (TNF-alpha) interleukin 6 (IL-6), IL-8, and vascular endothelial growth factor, factors that all contribute to tumor neovascularization and to the development of Kaposi sarcoma (KS) lesions. Ritonavir also suppressed the expression of vascular cell adhesion molecule 1, intercellular adhesion molecule 1, and E-selectin, which correlated with a functional decrease in leukocyte adhesion. Transcriptional activation of nuclear factor-kappaB, as induced by the KS-promoting factor TNF-alpha, the HIV-1 Tat protein, or the human herpesvirus 8 protein ORF74, was inhibited by ritonavir. KS-derived cell lines underwent apoptosis in vitro after treatment with ritonavir at concentrations that are obtained in clinical therapy (3-15 microM). In a KS mouse xenotransplantation model, ritonavir inhibited tumor formation and progression by KS-derived cells. Taken together, these data suggest that ritonavir has antineoplastic effects that are independent from its ability to inhibit the HIV protease.
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PMID:Antitumorigenic effects of HIV protease inhibitor ritonavir: inhibition of Kaposi sarcoma. 1198 35

Coinfections with opportunistic and pathogenic bacteria induce human immunodeficiency virus (HIV) replication through microbial antigen activation of NF-kappaB. Here, we assessed whether HIV type 1 protease inhibitors (PI) block microbial antigen activation of NF-kappaB. Human microvessel endothelial cells were transiently transfected with either endothelial cell-leukocyte adhesion molecule NF-kappaB luciferase or interleukin 6 (IL-6) promoter luciferase constructs by using FuGENE 6, and they were treated with PI (nelfinavir, ritonavir, or saquinavir) prior to stimulation with the Toll-like receptor 4 (TLR4) and TLR2 ligands, with lipopolysaccharide (LPS), soluble Mycobacterium tuberculosis factor, or Staphylococcus epidermidis phenol-soluble modulin, respectively, or with tumor necrosis factor alpha (TNF-alpha). Luciferase activity was measured by using a Promega luciferase kit. TNF-alpha release from the supernatant was measured by enzyme-linked immunosorbent assay. Cell death was assessed by lactate dehydrogenase assay. We observed that PI pretreatment blocked the TLR2- and TLR4- as well as the TNF-alpha-mediated NF-kappaB activation, in a dose-dependent manner. PI pretreatment also blocked the LPS-induced IL-6 promoter transactivation and TNF-alpha secretion. These data suggest that PI block HIV replication not only by inhibiting the HIV protease but also by blocking the TLR- and TNF-alpha-mediated NF-kappaB activation and proinflammatory cytokine production. These findings may help explain the immunomodulatory effects of PI, and they suggest an advantage for PI-containing drug regimens in the treatment of HIV-infected patients who are coinfected with opportunistic and pathogenic bacteria.
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PMID:Human immunodeficiency virus type 1 protease inhibitors block toll-like receptor 2 (TLR2)- and TLR4-Induced NF-kappaB activation. 1538 51

Benjamin Castleman first described multicentric Castleman's disease (MCD) in a series of cases in 1954. Interest in MCD has grown in recent years following an association with human immunodeficiency virus (HIV) infection. Castleman's disease is separated into localized disease and MCD. The latter is characterized by polylymphadenopathy and multiorgan involvement. Histologically, Castleman's disease is divided into the hyalinized vascular form and a plasma cell variant, the former being more common in localized disease and the latter more common in MCD. MCD is associated with Kaposi's sarcoma herpesvirus (KSHV) infection, which is alternatively termed human herpesvirus 8 (HHV8). This virus encodes a homologue of interleukin 6 (vIL 6), which may mediate some systemic features of MCD. The diagnosis of Castleman's disease is established by biopsy and treatment is often based on published case reports only, as there are no randomized trials of therapy. Surgery has less of a role in MCD than in localized disease, but debulking by splenectomy may be useful to alleviate haematological sequelae. Systemic treatments for MCD have included chemotherapy, anti-herpesvirus treatments to reduce the KSHV viral load, highly active antiretroviral therapy (HAART) to reduce HIV viraemia and latterly monoclonal antibodies against both IL 6 and CD20. The introduction of HAART has altered the natural history of HIV infection; however, its impact on MCD is difficult to ascertain. Optimization and consensus in treatment of these patients remains a target for the future.
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PMID:Fifty years of multicentric Castleman's disease. 1576 13

Human immunodeficiency virus type 1 (HIV-1) and related primate lentiviruses are known to enter the central nervous system (CNS) during the primary phase of infection. Neuroinvasion by simian immunodeficiency virus and simian human immunodeficiency virus (SHIV) is characterized by transient meningitis and astrocytosis. In this report, we used targeted cytokine cDNA arrays to analyze cortical brain tissue from four pig-tailed macaques inoculated for 2 weeks with pathogenic SHIV(50OLNV) and a normal age-matched pig-tailed macaque. Our results revealed that eight genes were significantly upregulated in all four macaques. These included: leukocyte interferon inducible peptide, corticotrophin releasing factor receptor 1, interleukin 6, CDW40 antigen, cysteine-rich fibroblast growth factor, neurotrophin 3, ciliary neurotrophin factor receptor and cripto-1. The upregulation of three of these genes was confirmed by reverse transcriptase PCR (RT-PCR). Since cripto-1 had not been previously identified within specific cell types within the primate central nervous system, we performed immunohistochemical studies, which revealed the presence of cripto-1 in neurons. RT-PCR studies demonstrated that cripto-1 mRNA was widely expressed in the CNS. These results indicate that immunomodulatory genes are upregulated during the primary phase of infection of the central nervous system. Cripto-1, which acts as a survival factor in tumor cells and may be neuroprotective, is expressed in neurons within the CNS and is upregulated during viral invasion.
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PMID:Early dysregulation of cripto-1 and immunomodulatory genes in the cerebral cortex in a macaque model of neuroAIDS. 1708 29

Because bone marrow histology in multicentric Castleman disease in human immunodeficiency virus-negative patients is not well reported, we investigated sequential bone marrow biopsies of 3 affected human immunodeficiency virus-negative patients, of which one was human herpes virus 8 (HHV8)-positive. The histologic evaluation of the bone marrow revealed lymphoid follicles with regressed germinal centers in 1 patient. Another patient showed tumorlike but bland polyclonal plasmacytosis with large perivascular plasma cell clusters. The HHV8-positive patient revealed interstitial HHV8-positive cells accompanied by a mild plasmacytosis. The atypical lymphoid follicles could be regarded as a bone marrow manifestation of multicentric Castleman disease, whereas the plasmacytosis most likely is the result of excess interleukin 6 production. The presence of HHV8-positive cells within the bone marrow may indicate the dissemination of the virus in a compromised immune system.
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PMID:Bone marrow findings in multicentric Castleman disease in HIV-negative patients. 1732 81

We addressed the role of plasmacytoid dendritic cells (PDC) in protection against AIDS in nonpathogenic simian immunodeficiency virus (SIVagm) infection in African green monkeys (AGMs). PDC were monitored in blood and lymph nodes (LNs) starting from day 1 postinfection. We observed significant declines in blood during acute infection. However, PDC then returned to normal levels, and chronically infected AGMs showed no decrease of PDC in blood. There was a significant increase of PDC in LNs during acute infection. Blood PDC displayed only weak alpha interferon (IFN-alpha) responses to TLR9 agonist stimulation before infection. However, during acute infection, both blood and LN PDC showed a transiently increased propensity for IFN-alpha production. Bioactive IFN-alpha was detected in plasma concomitant with the peak of viremia, though levels were only low to moderate in some animals. Plasma interleukin 6 (IL-6) and IL-12 were not increased. In conclusion, PDC were recruited to the LNs and displayed increased IFN-alpha production during acute infection. However, increases in IFN-alpha were transient. Together with the lack of inflammatory cytokine responses, these events might play an important role in the low level of T-cell activation which is associated with protection against AIDS in nonpathogenic SIVagm infection.
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PMID:Plasmacytoid dendritic cell dynamics and alpha interferon production during Simian immunodeficiency virus infection with a nonpathogenic outcome. 1838 27


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