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

---

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

The ROD strain of the human immunodeficiency virus type 2 (HIV-2) was used to produce monoclonal antibodies. Virus grown in CEM cells was partially purified by ultracentrifugation and solubilized in a buffer containing Triton X-100. BALB/c mice were inoculated intraperitoneally with 50 micrograms of solubilized virus preparations mixed 1:1 with complete Freund's adjuvant. Animals were boosted on day 28 and sacrificed on day 31. Spleen cells from the immunized animals were fused with SP20/Ag 14 myeloma cells and cultured in HAT medium. Following selection of the hybrids of interest by an HIV-2 ELISA procedure, hybridomas were cloned twice by limiting dilution. Six clones were found to produce antibodies that reacted with HIV-2 antigens as judged by ELISA. These antibodies were concentrated by ammonium sulfate precipitation, and analyzed by the Western blot procedure. Monoclonal antibodies specifically reactive to an HIV protein of 68 KD were obtained. These antibodies did not react with an HIV-2 band of 55 KD. These data showed that the monoclonal antibodies recognized the carboxy terminal region (the RNAse H domain) of the HIV-2 retrotranscriptase enzyme.
...
PMID:Production of monoclonal antibodies to human immunodeficiency virus type-2. 128 63

In a search for compounds active against human immunodeficiency virus type 1 (HIV-1), it was found that the novel low-molecular weight immunoenhancer ammonium trichloro(dioxyethylene-O,O'-) tellurate (AS101) suppresses production of HIV-1 in vitro. Treatment of HIV-1-infected peripheral blood mononuclear cells (PBMC) with increasing concentrations of AS101 resulted in substantial inhibition of virus production as measured by both reverse transcriptase (RT) activity and antigen presence in supernatants of treated cells. AS101 had no effect on PBMC viability, growth, or morphology up to a concentration of 15 microM for 14 days. To elucidate a possible mechanism for the inhibition of AS101, we have analyzed the effect of the drug on the catalytic functions associated with HIV RT, namely the RDDP, DDDP, and RNase H activities. RDDP and DDDP activities were impaired by the drug with calculated IC50 value of about 4 microM. On the other hand, the RNase H activity was less sensitive to AS101, with an apparent IC50 value of about 30 microM. The anti-HIV-1 activity of AS101 as reflected by inhibition of the different catalytic functions associated with viral RT, in the absence of drug-related toxicity to lymphocytes, together with its immunomodulating activity strongly argues in favor of its evaluation, as a therapeutic agent for patients with HIV infection.
...
PMID:Inhibition of the reverse transcriptase activity and replication of human immunodeficiency virus type 1 by AS 101 in vitro. 138 Dec 5

A method for the purification of a truncated, biologically active human immunodeficiency virus type 1 (HIV-1) trans-activator (rTAT) from recombinant Escherichia coli is reported here. The purification steps utilized include mild extraction (French press), concentration by ammonium sulfate precipitation, chromatography in 8 M urea on an S-Sepharose fast-protein liquid chromatography column, and finally, resolution by C-4 reverse-phase high-performance liquid chromatography. After the final step, the rTAT is dried and stored under salt-free conditions. Amino acid compositional analysis and N-terminal sequence analysis confirm that the purified protein is rTAT. Unlike other methods reported for purification of recombinant HIV-1 trans-activator, our protocol uses urea instead of guanidine HCl. The rTAT is fully soluble in buffered solutions at concentrations exceeding 10 mg/ml, migrates as a single 14 kDa species on both sodium dodecyl sulfate-polyacrylamide gel electrophoresis (PAGE) and two-dimensional PAGE gels with a pI of 9.3 +/- 0.3. Additionally, the rTAT migrates as a monomer on size-exclusion chromatography columns under native conditions. Finally, purified rTAT exhibits trans-activator activity when introduced into appropriate reporter cells. Since rTAT is monomeric when tested by gel filtration, and yet exhibits biological activity, we conclude that the method of purification we have utilized is distinct from all other methods reported to date.
...
PMID:Purification of an active monomeric recombinant HIV-1 trans-activator. 142 16

A class of synthetic lignins (dehydrogenation polymers of p-coumaric acid, ferulic acid, and caffeic acid) inhibited cytopathogenicity of HIV-1 and HIV-2 infection. The ratio of cytotoxic to anti-HIV (human immunodeficiency virus) doses depended strongly on conditions during polymer preparation. The activity increased when polymers were treated with reducing agent NaBH4, whereas it decreased when treated with oxidizing agent ceric ammonium nitrate. The polymers inhibited expression of HIV-specific antigen in the infected cells and also inhibited HIV-binding to the cells, but not completely, even at doses that almost completely inhibited the HIV-induced cytopathogenic effect. These results suggest that lignin structure, regardless of whether synthetic or natural, may inhibit HIV replication by an unidentified process, and thus prove to be a new class of anti-HIV agents possibly effective in the treatment of AIDS (acquired immunodeficiency syndrome).
...
PMID:Lignified materials as medicinal resources. V. Anti-HIV (human immunodeficiency virus) activity of some synthetic lignins. 142 63

3'-Azido-3'-deoxythymidine (AZT), a nucleoside analog which has potent activity against the acquired immunodeficiency virus, is actively secreted by the mammalian kidney. In order to study the mechanism of renal drug transport, the effect of AZT on the organic cation and organic anion transport systems in rat renal brush border membrane vesicles was examined by using a rapid filtration assay. The following prototypic substrates were used: [3H]N1-methylnicotinamide and [3H]tetraethylammonium for organic cations and p-[3H]aminohippurate for an organic anion. AZT inhibited pH-driven [3H]N'-methylnicotinamide transport (pHi = 6.0, pH0 = 7.5), but not as effectively as mepiperphenidol (MEPI), a known organic cation transport blocker; the corresponding IC50 values for AZT and MEPI were 2500 and 25 microM, respectively. Counterflow studies, which examined the capability of the drug to cross the plasma membrane, indicated that [3H] tetraethylammonium and MEPI trans-stimulated [3H]tetraethyl-ammonium uptake, but AZT did not. To clarify further the actions of AZT on the organic cation transporter, kinetic studies were undertaken. A Hanes-Woolf transformation of the data revealed that both AZT and MEPI inhibited [3H]N'-methylnicotinamide transport in a competitive manner. The specificity of competition was studied by looking at the effect of AZT on the organic anion transporter. Probenecid, a classical inhibitor of organic anion transport, blocked p-[3H]aminohippurate transport, but AZT did not. We conclude that AZT is a weak inhibitor of the renal brush border organic cation transport system.
...
PMID:Effect of 3'-azido-3'-deoxythymidine (AZT) on organic ion transport in rat renal brush border membrane vesicles. 153 Sep 72

Human immunodeficiency virus-1 reverse transcriptase-p66 is surprisingly unstable at 4 degrees C in a typical reverse transcriptase buffer that provides complete stability when enzyme is frozen at -70 degrees C. Incorporation of (rA)n(dT)12-18 template-primer in the buffer vastly improved solution stability of dilute enzyme. Incorporation of 1.0 M ammonium phosphate in the buffer promoted an unexpected and reproducible approximately 260% activation of enzyme. In addition, even enzyme that had been inactivated to 13% of its initial activity could be reactivated to the same approximately 260% higher activity level indicating a reversible interconversion of two forms of the enzyme. The effects of chaotropic and antichaotropic salts coupled with a prior observation of p66 monomer-dimer equilibrium provide suggestive evidence that these two forms of enzyme are monomeric and dimeric p66.
...
PMID:Stabilization and activation of recombinant human immunodeficiency virus-1 reverse transcriptase-P66. 169 Sep 91

Simian immunodeficiency virus protease (SIV-PR) was produced in Escherichia coli with a recombinant expression system in which the mature enzyme autoprocessed from a precursor form. Recombinant SIV and HIV-1 (human immunodeficiency virus, type 1) proteases were purified from bacterial cell lysates by use of sequential steps of ammonium sulfate precipitation and size-exclusion and ion-exchange chromatography. The amino acid composition, amino-terminal sequence, and molecular weight (monomer) of the recombinant SIV-PR were in accord with that of the 99 amino acid polypeptide predicted from the SIVMac-PR nucleotide sequence. The active form of SIV-PR was shown to be dimeric by gel filtration chromatography. Inhibition by pepstatin A, time-dependent inactivation by 1,2-epoxy-3-(4-nitrophenoxy)propane, and pH rate profiles using oligopeptide substrates demonstrated that SIV-PR behaves as an aspartic protease. Recombinant HIV-1 Pr55gag precursor was processed in vitro by SIV-PR and HIV-1 PR with indistinguishable proteolytic patterns upon NaDodSO4-polyacrylamide gel electrophoresis. Oligopeptide substrates for HIV-1 PR were found to be suitable substrates for recombinant SIV-PR with the exception of a peptide containing the site identified for p66/p51 cleavage (Phe*Tyr) within HIV-1 reverse transcriptase (RT). Several synthetic peptide analogue inhibitors of HIV-1 PR were also potent inhibitors of SIV-PR, indicating that SIV infection in macaques and rhesus monkeys should be useful models for the preclinical evaluation of acquired immunodeficiency syndrome (AIDS) therapeutics targeted towards the virally encoded HIV-1 protease.
...
PMID:Purification and biochemical characterization of recombinant simian immunodeficiency virus protease and comparison to human immunodeficiency virus type 1 protease. 188 29

A polyoxomolybdoeuropate PM-104 (NH4)12H2[Eu4(MoO4)(H2O)16(Mo7O24)4].13H2O was found to be a potent inhibitor of the growth of human immunodeficiency virus type 1 (HIV-1), a causative agent of acquired immunodeficiency syndrome (AIDS). On the basis of TI50 [median cytotoxic concentration (CC50)/median effective concentration (EC50)], the in vitro anti-HIV-1 activity of PM-104 is favorably comparable to that of a heteropolyoxotungstate PM-19 K7[PTi2W10O40].6H2O, which is one of the most potent HIV-1 inhibitors among the polyoxometalates so far tested. The heteropolyoxomolybdate with a potent anti-HIV-1 activity is introduced for the first time in this communication.
...
PMID:Antiviral activity of polyoxomolybdoeuropate PM-104 against human immunodeficiency virus type 1. 193 91

Replacing the Pseudomonas exotoxin A (PE) cell binding domain with the human immunodeficiency virus (HIV) gp120 binding domain from CD4 yields a hybrid toxin (CD4-PE) with potential therapeutic use in treating acquired immunodeficiency syndrome (AIDS). To find the most therapeutically potent combination of CD4 and PE four different hybrid toxins composed of one [CD4(122)] or two [CD4(181)] Ig-like CD4 domains and sequences of PE where the binding domain was partially [PE(392)] or completely [PE(364)] removed were constructed and expressed in Escherichia coli. The number of CD4 domains determined the binding affinity to gp120 and in cell viability assays the window between specific and nonspecific cytotoxicity. The length of PE determined the potency of the drug. The optimal hybrid toxin was composed of two Ig-like domains of CD4 and PE(392). Investigation of the internalization mechanism of CD4-PE revealed that the hybrid toxin binds to target cells and is endocytosed within one hour. However, more than 6 hours are required for maximum translation inhibition. In contrast to PE which is inhibited by ammonium chloride treatment, cell toxicity of CD4-PE is not affected by ammonium chloride. Further investigations showed that the acid-induced hydrophobicity change which is required for membrane translocation is also observed with CD4-PE but at significantly higher pH than with PE.
...
PMID:CD4-Pseudomonas exotoxin hybrid proteins: modulation of potency and therapeutic window through structural design and characterization of cell internalization. 206 20

We investigated whether Rous sarcoma virus (RSV) infects cells through a pH-independent or a low-pH-dependent pathway. To do this, the effects of lysosomotropic agents and acid pretreatment on RSV infectivity of, and fusion with, chicken embryo fibroblasts (CEFs) were studied. High concentrations of lysosomotropic agents (ammonium chloride and monensin) did not inhibit virus infectivity: equal titers of RSV were produced in the presence and absence of these agents. Similarly, low-pH pretreatment did not inhibit RSV infectivity. In parallel experiments, lysosomotropic agents and acid pretreatment completely abolished the ability of influenza virus to infect CEFs. To monitor the fusion activity of RSV directly, the viral membrane was labeled with the fluorescent lipid probe octadecyl rhodamine at a self-quenching concentration. Upon fusion with a host cell, the probe is diluted in the cell membrane, resulting in fluorescence dequenching (D. Hoekstra, T. de Boer, K. Klappe, and J. Wilschut, Biochemistry 23:5675-5681, 1984). In this assay, fusion of RSV with CEFs was found to occur in both a time-dependent and a strictly temperature-dependent fashion. No fusion occurred unless cells with prebound virus were warmed to temperatures greater than 20 degrees C. Fusion, but not binding, was abolished if virus was pretreated with low concentrations of glutaraldehyde. High concentrations of ammonium chloride had no effect on fusion of RSV with CEFs but greatly diminished the ability of influenza virus and Semliki Forest virus to fuse with CEFs. Similarly, acid pretreatment of RSV had no effect on fusion with CEFs while markedly inhibiting fusion of both influenza and Semliki Forest viruses. Collectively, our results show that RSV fusion with and hence infection of CEFs does not require exposure of the virus to low pH. In this respect, RSV resembles another retrovirus, human immunodeficiency virus.
...
PMID:Fusion of Rous sarcoma virus with host cells does not require exposure to low pH. 216 89


1 2 3 4 5 6 7 8 Next >>

---