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

We examined the interplay between cytokines and adjuvants to optimize the induction of CTL by a mucosal HIV peptide vaccine. We show synergy between IL-12 and GM-CSF when administered together with the HIV peptide PCLUS3-18IIIB and cholera toxin (CT) in the induction of CTL activity and protection against mucosal viral transmission. Further, we examine the efficacy of mutant Escherichia coli labile toxin, LT(R192G), as a less toxic adjuvant than CT. LT(R192G) was as effective as or more effective than CT at inducing a mucosal CTL response. Moreover, LT(R192G) was as effective without IL-12 as CT was when combined with IL-12, and the response elicited by LT(R192G) with the vaccine was not further enhanced by the addition of IL-12. GM-CSF synergized with LT(R192G) without exogenous IL-12. Therefore, LT(R192G) may induce a more favorable cytokine response by not inhibiting IL-12 production. In particular, less IL-4 is made after LT(R192G) than CT immunization, and the response is less susceptible to anti-IL-12 inhibition. Thus, the choice of mucosal adjuvant affects the cytokine environment, and the mucosal response and protection can be enhanced by manipulating the cytokine environment with synergistic cytokine combinations incorporated in the vaccine.
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PMID:Interplay of cytokines and adjuvants in the regulation of mucosal and systemic HIV-specific CTL. 1108 85

Nonreplicating vectors are being considered in HIV-1 vaccine design. However, nonreplicating viruses are typically weak immunogens, leading to efforts to target the vaccine to mature dendritic cells (DCs). We have studied a single-cycle form of HIV-1, prepared by pseudotyping envelope-defective HIV-1 plasmids with the envelope from vesicular stomatitis virus (VSV) G protein (VSV-G), to which most humans lack preexisting immunity. The nonreplicating, VSV/HIV-1 efficiently infected the immature stage of DC development, in this case represented by monocytes cultured with GM-CSF and IL-4. A majority of the cells reverse transcribed the HIV-1 RNA, and a minority expressed gag protein. The infected populations were further matured with CD40 ligand, leading to strong stimulation of autologous T cells from HIV-1-infected individuals, but not controls. Enriched CD8(+) T cells from 12/12 donors released IFN-gamma (50-300 enzyme-linked immunospots/200,000 T cells) and proliferated. Macrophages were much less efficient in expanding HIV-1-responsive T cells, and bulk mononuclear cells responded weakly to VSV/HIV-1. CD4(+) T cells from at least half of the donors showed strong responses to VSV/HIV-1-infected DCs. Presentation to CD8(+) T cells, but not to CD4(+), was primarily through an endogenous pathway, because the responses were markedly reduced if envelope-defective virus particles or reverse transcriptase inhibitors were added. Therefore, nonreplicating vaccines can be targeted to immature DCs, which upon further maturation induce combined and robust CD4(+) and CD8(+) immunity.
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PMID:Dendritic cells, infected with vesicular stomatitis virus-pseudotyped HIV-1, present viral antigens to CD4+ and CD8+ T cells from HIV-1-infected individuals. 1108 7

Spontaneous secretion of interleukin 8 (IL-8) was higher in latently infected U1 cells than in acutely infected or uninfected parental U937 cells. However, the induction of IL-8 by various cytokines (IL-1 alpha, TNF-alpha, IL-6, TNF-beta, GM-CSF, IFN-gamma) was significantly reduced in U1 cells. Cytokine modulation of IL-8 production in U937 cells acutely infected with a T cell-tropic strain (IIIB) or monocytotropic strain (ADA) of human immunodeficiency virus 1 (HIV-1) (HIV-1IIIB and HIV-1ADA) was variable and showed strain-specific differences. The obtained results showed that the in vitro induction of IL-8 is impaired in promonocytic cells latently infected with HIV-1 and is differently modulated under acute conditions of infection depending on the IL-8 inducing cytokine and on the infecting virus strain.
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PMID:Cytokine-induced interleukin-8 production is depressed in chronic as opposed to acute human immunodeficiency virus 1 infection of promonocytic cells. 1115 65

Langerhans cells (LC) represent dendritic cells (DC) within mucosal epithelium that are purported initial targets for HIV following sexual exposure to virus. Here, morphologic, phenotypic, functional and HIV infection experiments were performed using monocyte-derived DC cultured in the presence of GM-CSF, IL-4 and TGF-beta1 (G4T-DC), GM-CSF and IL-4 (G4-DC), and G4T-DC incubated for an additional 3 days with CD40 ligand (CD40L-DC). G4T-DC, which demonstrated characteristics of immature LC, could be productively infected by either R5- or X4-HIV strains. Infection levels, however, were markedly lower than those observed in immature G4-DC. Surprisingly, CD40L-DC, which demonstrated features of mature LC, could be productively infected with HIV at higher levels than immature G4T-DC. Productive HIV infection in these three DC populations correlated positively with cell surface expression of CD4, CCR5 and CXCR4. We suggest that low levels of HIV infection in LC-like G4T-DC indicate an inefficient mechanism by which HIV can initially infect individuals, perhaps explaining the relative difficulty in becoming infected during sexual exposure to virus. In addition, enhanced HIV infection in LC-like G4T-DC following CD40L treatment suggests a mechanism by which inflammatory CD40L(+) T cells, if present in mucosal tissue, could lead to increased HIV transmission rates.
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PMID:Low levels of productive HIV infection in Langerhans cell-like dendritic cells differentiated in the presence of TGF-beta1 and increased viral replication with CD40 ligand-induced maturation. 1118 99

Maturation of dendritic cells (DC) is known to result in decreased capacity to produce HIV due to postentry block of its replicative cycle. In this study, we compared the early phases of this cycle in immature DC (iDC) and mature DC (mDC) generated from monocytes cultured with GM-CSF and IL-4, trimeric CD40 ligand (DC(CD40LT)), or monocyte-conditioned medium (DC(MCM)) being added or not from day 5. Culture day 8 cells exposed to X4 HIV-1(LAI) or R5 HIV-1(Ba-L) were analyzed by semiquantitative R-U5 PCR, which detects total HIV DNA. CXC chemokine receptor 4(low) (CXCR4(low)) CCR5(+) iDC harbored similar viral DNA amounts when exposed to either strain. HIV-1(LAI) entered more efficiently into DC(CD40LT) or DC(MCM) with up-regulated CXCR4. CCR5(low) DC(CD40LT) still allowed entry of HIV-1(Ba-L), whereas CCR5(-) DC(MCM) displayed reduced permissivity to this virus. Comparing amounts of late (long terminal repeat (LTR)-gag PCR) and total (R-U5 PCR) viral DNA products showed that HIV-1(Ba-L) reverse transcription was more efficient than that of HIV-1(LAI), but was not affected by DC maturation. Southern blot detection of linear, circular, and integrated HIV DNA showed that maturation affected neither HIV-1 nuclear import nor integration. When assessing virus transcription by exposing iDC to pNL4-3.GFP or pNL4-3.Luc viruses pseudotyped with the G protein of vesicular stomatitis virus (VSV-G), followed by culture with or without CD40LT or MCM, GFP and luciferase activities decreased by 60-75% in mDC vs iDC. Thus, reduced HIV replication in mDC is primarily due to a postintegration block occurring mainly at the transcriptional level. We could not relate this block to altered expression and nuclear localization of NF-kappa B proteins and SP1 and SP3 transcription factors.
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PMID:The maturation of dendritic cells results in postintegration inhibition of HIV-1 replication. 1123 20

Chemokine receptors are subjected to heterologous desensitization by activation of formyl peptide receptors. We investigated the cross-talk between formyl peptide receptors and the chemokine receptor CCR5 in human monocyte-differentiated immature dendritic cells (iDC). Monocytes cultured with GM-CSF and IL-4 for 4 days exhibit markers characteristic of iDC and maintain the expression of both formyl peptide receptors FPR and FPRL1, as well as CCR5. Pretreatment of iDC with W peptide (WKYMVm), a potent agonist for FPR and FPRL1 but with preference for FPRL1, resulted in down-regulation of CCR5 from the cell surface and reduced cell response to the CCR5 ligands through a PKC-dependent pathway. Furthermore, W peptide induced a PKC-dependent phosphorylation of CCR5 and inhibited infection of iDC by R5 HIV-1. Our results indicate that the expression and functions of CCR5 in iDC can be attenuated by W peptide, which activates formyl peptide receptors, and suggest an approach to the design of novel anti-HIV-1 agents.
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PMID:Desensitization of chemokine receptor CCR5 in dendritic cells at the early stage of differentiation by activation of formyl peptide receptors. 1135 33

A study to determine if GM-CSF (Leukine), in addition to standard therapies, will delay HIV disease progression and death by enhancing immune function is in clinical trials around the United States. Participants can be on any standard anti-HIV and anti-opportunistic infection regimens. A phone number is provided for further information.
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PMID:Study of GM-CSF enrolling. 1136 71

The AIDS Vaccine Evaluation Group (AVEG) has begun enrollment in three new clinical trials that are testing a novel route of immunization (AVEG 027), an innovative vaccine strategy (AVEG 028), and a new adjuvant, or vaccine booster (AVEG 033). AVEG 027 is studying an experimental vaccine being applied topically to specific mucosal sites and then measuring the antibodies created at those sites. Since HIV is often transmitted across mucosal surfaces, it is believed a vaccine that induces mucosal antibodies will work better than other types of vaccines. AVEG 028 uses a weakened form of Salmonella bacteria (a bacteria that reproduces exclusively in human cells) to present an HIV protein to the immune system and induce immune responses. Finally, AVEG 033 combines GM-CSF with a canarypox virus-based vector containing HIV genes to determine if GM-CSF can improve the immune response to the vector. Additional information on each trial is provided.
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PMID:Three new AIDS vaccine trials begin testing novel concepts. 1136 91

Dr. Mark Gilbert, Medical Director of the biopharmaceutical company Immunex, explains that Highly Active Antiretroviral Therapy (HAART) has provided a foundation to begin addressing the effects of therapy on the immune system. Immunex is focusing on the role that Leukine, a recombinant, yeast-derived GM-CSF, has on both advanced AIDS and the early onset of HIV. A Phase III trial is evaluating whether Leukine can reduce the incidence of opportunistic infections and death in 300 people with AIDS. Dr. Gilbert discusses the importance of the thymus for T cell development and its effect on immune system functions. Immunex is searching for a method to either maintain or to restore the immune system. Restoring the thymus may restore host immunity; however, very little is known about the thymus. According to Gilbert, the most promising idea for restoring immune function is intermittent low-dose interleukin-2 (IL-2). HIV-positive individuals using HAART therapy should consider talking to a health care provider about immune modulation therapy.
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PMID:A view of the future: Dr. Mark Gilbert of Immunex talks about immune based therapy. Interview by Robert Nielsen. 1136 10

Research has demonstrated that increased expression of CCR5 in monocytes/macrophages increases a person's susceptibility to HIV-1 infection. Activating macrophages by treatment with the cytokine GM-CSF appears to decrease susceptibility to HIV-1 infection by decreasing CCR5 expression. This may explain why HIV patients treated with GM-CSF appear to resist increased HIV-1 replication.
HIV Hotline 1998 Mar
PMID:CCR5 mutations and HIV susceptibility. 1136 56


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