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Query: UMLS:C0038362 (stomatitis)
 8,852 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Live attenuated vaccines prepared from simian immunodeficiency virus (SIV) have provided the best protective immunity in challenge experiments. In animals vaccinated with attenuated SIV, immune responses may be elicited owing to endogenous expression of native SIV proteins and/or antigen presentation in the native replication site of virus. However, replication-competent viral vaccines raise safety concerns for clinical trials in humans. To ensure the safety and maintain the immunogenicity of a live, attenuated vaccine, we have developed a replication-defective HIV pseudotyped with vesicular stomatitis virus G protein (VSV-G). The polymerase gene of HIV was truncated to construct the replication-defective HIV. This pseudotyped HIV can infect many cell types, including human and simian cells, and undergoes only one round of replication. Furthermore, antibody immune response can be detected in mice immunized with VSV-G-pseudotyped replication-defective HIV.
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PMID:Replication-defective HIV as a vaccine candidate. 976 8

Previously we designed novel pseudotyped high-titer replication defective human immunodeficiency virus type 1 (HIV-1) vectors to deliver genes into nondividing cells (J. Reiser, G. Harmison, S. Kluepfel-Stahl, R. O. Brady, S. Karlsson, and M. Schubert, Proc. Natl. Acad. Sci. USA 93:15266-15271, 1996). Since then we have made several improvements with respect to the safety, flexibility, and efficiency of the vector system. A three-plasmid expression system is used to generate pseudotyped HIV-1 particles by transient transfection of human embryonic kidney 293T cells with a defective packaging construct, a plasmid coding for a heterologous envelope (Env) protein, and a vector construct harboring a reporter gene such as neo, ShlacZ (encoding a phleomycin resistance/beta-galactosidase fusion protein), HSA (encoding mouse heat-stable antigen), or EGFP (encoding enhanced green fluorescent protein). The packaging constructs lack functional Vif, Vpr, and Vpu proteins and/or a large portion of the Env coding region as well as the 5' and 3' long terminal repeats, the Nef function, and the presumed packaging signal. Using G418 selection, we routinely obtained vector particles pseudotyped with the vesicular stomatitis virus G glycoprotein (VSV-G) with titers of up to 8 x 10(7) CFU/microgram of p24, provided that a functional Tat coding region was present in the vector. Vector constructs lacking a functional Tat protein yielded titers of around 4 x 10(6) to 8 x 10(6) CFU/microgram of p24. Packaging constructs with a mutation within the integrase (IN) core domain profoundly affected colony formation and expression of the reporter genes, indicating that a functional IN protein is required for efficient transduction. We explored the abilities of other Env proteins to allow formation of pseudotyped HIV-1 particles. The rabies virus and Mokola virus G proteins yielded high-titer infectious pseudotypes, while the human foamy virus Env protein did not. Using the improved vector system, we successfully transduced contact-inhibited primary human skin fibroblasts and postmitotic rat cerebellar neurons and cardiac myocytes, a process not affected by the lack of the accessory proteins.
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PMID:High-titer human immunodeficiency virus type 1-based vector systems for gene delivery into nondividing cells. 976 32

A bicistronic human immunodeficiency virus type 1 (HIV-1)-based vector is described in which the expression of a selectable marker and a second gene of interest are forcibly coupled by means of an internal ribosome entry site. The vector provides high-level expression of the coselected gene in approximately 90% of transduced cells and has been used to express an endoplasmic reticulum-targeted single-chain antibody (intrabody) directed against a subunit of the interleukin-2 receptor, IL-2R alpha. In the established T cell line Kit225 and also in primary human T cells stably transduced with the intrabody vector, the cell surface expression of IL-2R alpha could be reduced to a low or undetectable level. Responsiveness to IL-2 was reduced 10-fold in the IL-2R alpha-negative cells, consistent with a lack of high-affinity IL-2 receptors. Pseudotyping of the HIV-1 core with the vesicular stomatitis virus G protein improved particle stability by two- to three-fold and enhanced vector entry into established T cell lines up to 230-fold. Vector entry into primary human T cells was most efficient when the amphotropic murine leukemia virus envelope was used. The forced, high-expression capability of the bicistronic vector, together with the capacity of HIV-1 vectors to infect nondividing cells, make this an attractive tool for the genetic manipulation of primary cell types.
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PMID:Intrabody-mediated knockout of the high-affinity IL-2 receptor in primary human T cells using a bicistronic lentivirus vector. 979 68

Autologous leukemia cells engineered to express immune-stimulating molecules may be used to elicit antileukemia immune responses. Gene delivery to human B-precursor acute lymphoblastic leukemia (ALL) cells was investigated using the enhanced green fluorescent protein (EGFP) as a reporter gene, measured by flow cytometry. Transfection of the Nalm-6 and Reh B-precursor ALL leukemia cell lines with an expression plasmid was investigated using lipofection, electroporation, and a polycationic compound. Only the liposomal compound Cellfectin showed significant gene transfer (3.9% to 12% for Nalm-6 cells and 3.1% to 5% for Reh cells). Transduction with gibbon-ape leukemia virus pseudotyped Moloney murine leukemia virus (MoMuLV)-based retrovirus vectors was investigated in various settings. Cocultivation of ALL cell lines with packaging cell lines showed the highest transduction efficiency for retroviral gene transfer (40.1% to 87.5% for Nalm-6 cells and 0.3% to 9% for Reh cells), followed by transduction with viral supernatant on the recombinant fibronectin fragment CH-296 (13% to 35.5% for Nalm-6 cells and 0.4% to 6% Reh cells), transduction on human bone marrow stroma monolayers (3.2% to 13.3% for Nalm-6 cells and 0% to 0.2% Reh cells), and in suspension with protamine sulfate (0.7% to 3.1% for Nalm-6 cells and 0% for Reh cells). Transduction of both Nalm-6 and Reh cells with human immunodeficiency virus-type 1 (HIV-1)-based lentiviral vectors pseudotyped with the vesicular stomatitis virus-G envelope produced the best gene transfer efficiency, transducing greater than 90% of both cell lines. Gene delivery into primary human B-precursor ALL cells from patients was then investigated using MoMuLV-based retrovirus vectors and HIV-1-based lentivirus vectors. Both vectors transduced the primary B-precursor ALL cells with high efficiencies. These studies may be applied for investigating gene delivery into primary human B-precursor ALL cells to be used for immunotherapy.
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PMID:Gene delivery to human B-precursor acute lymphoblastic leukemia cells. 980 45

Virus inactivation by cold treatment with beta-propiolactone (BPL) was investigated in human cryo poor plasma and purified IgG concentrates spiked with relevant human viruses or appropriate animal model viruses. The samples were treated with 0.1 or 0.25% BPL for 300 or 480 min, respectively. Residual infectivity was determined by standard microtitration assays on tissue culture cells. The inactivation of all viruses tested was more effective in IgG than in plasma. IgG: R1=4-5.5 log10 for vesicular stomatitis virus (VSV). Semliki Forest virus (SFV), bovine virus diarrhoea virus (BVDV), murine encephalomyelitis virus (MEV), feline calicivirus (FVC), suid parvovirus (PPV), simian virus 40 (SV40); R1=2-4 log10 for suid herpesvirus type 1 (SHV-1), bovine herpesvirus type 1 (BHV-1), human immunodeficiency virus type 2 (HIV-2), simian immunodeficiency virus (SIVagm3). Plasma: R1=3-5 log10 for VSV, SFV, BVDV, SHV-1, MEV:R1=0-3 log10 for HIV-1, SIVagm3 BHV-1, FCV, PPV, SV40. After addition of SIVagm3, HIV-2, and PPV to plasma or IgG, spontaneous inactivation without further addition of BPL was observed. These results demonstrate that treatment with BPL has a limited capacity to inactivate viruses. Different inactivation kinetics were observed in plasma and IgG concentrates. Therefore, virus inactivation by BPL must be tested for individual blood products independently and should not be extrapolated from other model systems.
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PMID:Inactivation of viruses by beta-propiolactone in human cryo poor plasma and IgG concentrates. 981 21

We have identified mutations in the human immunodeficiency virus type 1 (HIV-1) matrix protein (MA) which block infectivity of virions pseudotyped with murine leukemia virus (MuLV) envelope (Env) glycoproteins without affecting infectivity conferred by HIV-1 Env or vesicular stomatitis virus G glycoproteins. This inhibition is very potent and displays a strong transdominant effect; infectivity is reduced more than 100-fold when wild-type and mutant molecular clones are cotransfected at a 1:1 ratio. This phenomenon is observed with both ecotropic and amphotropic MuLV Env. The MA mutations do not affect the incorporation of MuLV Env into virions. We demonstrate that in HIV-1 virions pseudotyped with MuLV Env, the HIV-1 protease (PR) efficiently catalyzes the cleavage of the p15(E) transmembrane (TM) protein to p12(E). Immunoprecipitation analysis of pseudotyped virions reveals that the mutant MA blocks this HIV-1 PR-mediated cleavage of MuLV TM. Furthermore, the transdominant inhibition exerted by the mutant MA on wild-type infectivity correlates with the relative level of p15(E) cleavage. Consistent with the hypothesis that abrogation of infectivity imposed by the mutant MA is due to inhibition of p15(E) cleavage, mutant virions are significantly more infectious when pseudotyped with a truncated p12(E) form of MuLV Env. These results indicate that HIV-1 Gag sequences can influence the viral PR-mediated processing of the MuLV TM Env protein p15(E). These findings have implications for the development of HIV-1-based retroviral vectors pseudotyped with MuLV Env, since p15(E) cleavage is essential for activating membrane fusion and virus infectivity.
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PMID:Cleavage of the murine leukemia virus transmembrane env protein by human immunodeficiency virus type 1 protease: transdominant inhibition by matrix mutations. 981 95

Previous studies showed that the HIV-1 envelope (Env) protein was not incorporated into vesicular stomatitis virus (VSV) virions unless its cytoplasmic tail was replaced with that of the VSV glycoprotein (G). To determine whether the G tail provided a positive incorporation signal for Env, or if sequences in the Env tail prevented incorporation, we generated mutants of Env with its 150-amino-acid tail shortened to 29, 10, or 3 amino acids (Envtr mutants). Cells infected with VSV recombinants expressing these proteins or an Env-G tail hybrid showed similar amounts of Env protein at the surface. The Env-G tail hybrid or the Envtr3 mutant were incorporated at the highest levels into budding VSV virions. In contrast, the Envtr29 or Envtr10 mutants were incorporated poorly. These results defined a signal preventing incorporation within the 10 membrane-proximal amino acids of the Env tail. Confocal microscopy revealed that this signal functioned by causing localization of human immunodeficiency virus type 1 Env to plasma membrane domains distinct from the VSV budding sites, where VSV proteins were concentrated.
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PMID:A plasma membrane localization signal in the HIV-1 envelope cytoplasmic domain prevents localization at sites of vesicular stomatitis virus budding and incorporation into VSV virions. 983 88

The p6(Gag) protein of human immunodeficiency virus type 1 (HIV-1) is produced as the carboxyl-terminal sequence within the Gag polyprotein. The amino acid composition of this protein is high in hydrophilic and polar residues except for a patch of relatively hydrophobic amino acids found in the carboxyl-terminal 16 amino acids. Internal cleavage of p6(Gag) between Y36 and P37, apparently by the HIV-1 protease, removes this hydrophobic tail region from approximately 30% of the mature p6(Gag) proteins in HIV-1MN. To investigate the importance of this cleavage and the hydrophobic nature of this portion of p6(Gag), site-directed mutations were made at the minor protease cleavage site and within the hydrophobic tail. The results showed that all of the single-amino-acid-replacement mutants exhibited either reduced or undetectable cleavage at the site yet almost all were nearly as infectious as wild-type virus, demonstrating that processing at this site is not important for viral replication. However, one exception, Y36F, was 300-fold as infectious the wild type. In contrast to the single-substitution mutants, a virus with two substitutions in this region of p6(Gag), Y36S-L41P, could not infect susceptible cells. Protein analysis showed that while the processing of the Gag precursor was normal, the double mutant did not incorporate Env into virus particles. This mutant could be complemented with surface glycoproteins from vesicular stomatitis virus and murine leukemia virus, showing that the inability to incorporate Env was the lethal defect for the Y36S-L41P virus. However, this mutant was not rescued by an HIV-1 Env with a truncated gp41(TM) cytoplasmic domain, showing that it is phenotypically different from the previously described MA mutants that do not incorporate their full-length Env proteins. Cotransfection experiments with Y36S-L41P and wild-type proviral DNAs revealed that the mutant Gag dominantly blocked the incorporation of Env by wild-type Gag. These results show that the Y36S-L41P p6(Gag) mutation dramatically blocks the incorporation of HIV-1 Env, presumably acting late in assembly and early during budding.
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PMID:Mutational analysis of the hydrophobic tail of the human immunodeficiency virus type 1 p6(Gag) protein produces a mutant that fails to package its envelope protein. 984 2

We have studied the effects of CC-chemokines on human immunodeficiency virus type 1 (HIV-1) infection, focusing on the infectivity enhancement caused by RANTES. High RANTES concentrations increase the infectivity of HIV-1 isolates that use CXC-chemokine receptor 4 for entry. However, RANTES can have a similar enhancing effect on macrophagetropic viruses that enter via CC-chemokine receptor 5 (CCR5), despite binding to the same receptor as the virus. Furthermore, RANTES enhances the infectivity of HIV-1 pseudotyped with the envelope glycoprotein of murine leukemia virus or vesicular stomatitis virus, showing that the mechanism of enhancement is independent of the route of virus-cell fusion. The enhancing effects of RANTES are not mediated via CCR5 or other known chemokine receptors and are not mimicked by MIP-1alpha or MIP-1beta. The N-terminally modified derivative aminooxypentane RANTES (AOP-RANTES) efficiently inhibits HIV-1 infection via CCR5 but otherwise mimics RANTES by enhancing viral infectivity. There are two mechanisms of enhancement: one apparent when target cells are pretreated with RANTES (or AOP-RANTES) for several hours, and the other apparent when RANTES (or AOP-RANTES) is added during virus-cell absorption. We believe that the first mechanism is related to cellular activation by RANTES, whereas the second is an increase in virion attachment to target cells.
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PMID:Enhancement of human immunodeficiency virus type 1 infection by the CC-chemokine RANTES is independent of the mechanism of virus-cell fusion. 984 74

Interactions of human immunodeficiency virus type 1 (HIV-1) with hematopoietic stem cells may define restrictions on immune reconstitution following effective antiretroviral therapy and affect stem cell gene therapy strategies for AIDS. In the present study, we demonstrated mRNA and cell surface expression of HIV-1 receptors CD4 and the chemokine receptors CCR-5 and CXCR-4 in fractionated cells representing multiple stages of hematopoietic development. Chemokine receptor function was documented in subsets of cells by calcium flux in response to a cognate ligand. Productive infection by HIV-1 via these receptors was observed with the notable exception of stem cells, in which case the presence of CD4, CXCR-4, and CCR-5, as documented by single-cell analysis for expression and function, was insufficient for infection. Neither productive infection, transgene expression, nor virus entry was detectable following exposure of stem cells to either wild-type HIV-1 or lentivirus constructs pseudotyped in HIV-1 envelopes of macrophage-tropic, T-cell-tropic, or dualtropic specificity. Successful entry into stem cells of a vesicular stomatitis virus G protein-pseudotyped HIV-1 construct demonstrated that the resistance to HIV-1 was mediated at the level of virus-cell membrane fusion and entry. These data define the hematopoietic stem cell as a sanctuary cell which is resistant to HIV-1 infection by a mechanism independent of receptor and coreceptor expression that suggests a novel means of cellular protection from HIV-1.
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PMID:Intrinsic human immunodeficiency virus type 1 resistance of hematopoietic stem cells despite coreceptor expression. 984 79


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