Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0001175 (AIDS)
 120,706 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Functional studies assessed the cytolytic activity of the amino terminal peptide (FP-I; 23 residues 519-541) of the glycoprotein 41,000 (gp41) of the Human Immunodeficiency Virus Type-1 (HIV-1). Synthetically prepared FP-I efficiently hemolyzed human red blood cells at 37 degrees C, with 40% lysis at 32 microM. Kinetic studies indicated that FP-I induced maximal hemolysis in 30 min, probably through tight binding of the peptide with the red cell membrane. The Phe-Leu-Gly-Phe-Leu-Gly (residues 526-531) motif in FP-I apparently plays a critical role in lysis of red cells, since no hemolytic activity was observed for an amino-acid-substituted FP-I in which the unique Phe-Leu-Gly-Phe-Leu-Gly was converted to Ala-Leu-Gly-Ala-Leu-Gly. As neither smaller constituent peptides (e.g., residues 519-524 and residues 526-536) nor a N-terminal flanking peptide (e.g., residues 512-523) induced red cell hemolysis, the entire 23-residue (519-541) sequence of FP-I may be required for hemolytic activity. FP-I was also cytolytic with CD4(+)-bearing Hut-78 cells, with 40% lysis at approx. 150 microM. These results are consistent with an earlier hypothesis that the N-terminal peptide of gp41 may partially contribute to the in vivo cytopathic actions of HIV-1 infection (Gallaher, W.R. (1987) Cell 50, 327-328).
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PMID:The amino-terminal peptide of HIV-1 glycoprotein 41 lyses human erythrocytes and CD4+ lymphocytes. 135 63

An anti-human immunodeficiency virus (anti-HIV) protein capable of inhibiting HIV-1 infection and replication has been isolated and purified to homogeneity from Trichosanthes kirilowii. This protein, TAP 29 (Trichosanthes anti-HIV protein, 29 kDa), is distinct from trichosanthin [also known as GLQ 223 (26 kDa)] in size, N-terminal amino acid sequence, and cytotoxicity. In addition to three conservative substitutions--namely, Arg-29 to Lys, Ile-37 to Val, and Pro-42 to Ser--a total difference of residues 12-16 was found. TAP 29 yielded -Lys-Lys-Lys-Val-Tyr-, whereas trichosanthin has -Ser-Ser-Tyr-Gly-Val-. Although the two proteins exhibit similar anti-HIV activity, as measured by syncytium formation, p24 expression, and HIV reverse transcriptase activity, they differ significantly in cytotoxicity, as measured by their effects on cellular DNA and protein syntheses. At the dose level of the bioassays, 0.34-340 nM, trichosanthin demonstrates a dose-dependent toxic effect on host cells. TAP 29 displays no toxic effect, even at 100 X ID50, whereas trichosanthin demonstrates 38% and 44% inhibition on cellular DNA and protein synthesis, respectively. These results indicate that the therapeutic index of TAP 29 is at least two orders of magnitude higher than that of trichosanthin. Thus TAP 29 may offer a broader safe dose range in the treatment of AIDS.
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PMID:TAP 29: an anti-human immunodeficiency virus protein from Trichosanthes kirilowii that is nontoxic to intact cells. 171 84

The N-terminal region of the human immunodeficiency virus type 1 (HIV-1) gp41 appears to be involved in virus-cell membrane fusion. To study the influence of fusion domain structure on gp41 interaction with artificial lipid membranes, two families of peptides were synthesized. The peptides of the first family starting from the C-terminal Gly-532 of gp160 (BRU isolate) were assembled in a stepwise manner to N-terminus of gp41(Ala-517). These hydrophobic peptides, containing 10-16 amino acid residues (a.a.), were able to form channel-like current fluctuation through planar lipid membranes, and the longest 15-16 a.a. peptides lysed the liposomes. Peptides of the second family beginning from the C-terminal Arg-538 and continuing to Val-510 contained several hydrophilic amino acid residues. These 15-22 a.a. peptides also increased the conductance of planar lipid bilayers and lysed liposomes. The degree of liposome lysis depended upon peptide length and concentration. The attachment of gp120 C-terminal amino acid or peptides to N-terminus of 517-538 peptide resulted in complete loss of activity. The effects of the second family of peptides on membranes were reduced to a great extent at acidic pH. The conjugation of 22 a.a. Lys peptide with bovine serum albumin decreased its lytic activity. The circular dichroism study of these peptides revealed alpha-helix configuration in hydrophobic and aqueous media only for deca- and longer peptides. The electron microscopy of 22 a.a. peptide performed in the aqueous medium showed large spherical aggregates about 0.5-0.7 micron in diameter consisting of long filaments approximately 5 nm in diameter. Other tested peptides could generate only short strings. Thus, the effects of fusion peptides on lipid membranes depends on their sequence and length, secondary and tertiary structures, and freedom of their N-terminus.
AIDS Res Hum Retroviruses 1992 Jan
PMID:Investigation of human immunodeficiency virus fusion peptides. Analysis of interrelations between their structure and function. 173 43

Altered T cell adherence after human immunodeficiency virus 1 (HIV-1) infection may contribute to viral pathogenesis in the acquired immune deficiency syndrome. To address this hypothesis, we assessed mechanisms of T cell adherence to extracellular matrix proteins in vitro. We found that after HIV-1 infection, both chronically infected H9 CD4+ T cells and acutely infected primary peripheral blood lymphocytes acquired the ability to adhere to the extracellular matrix glycoprotein fibronectin, to a lesser extent to type IV collagen and laminin, but not to type I collagen. H9 cells chronically infected with two of the three HIV-1 strains studied showed approximately a sevenfold increase in attachment to fibronectin, while the same cells infected with the human retrovirus HIV-2 did not. Adhesion was accompanied by changes in morphology, including marked spreading and increased filopodia. These alterations were not blocked by the protein kinase C inhibitor H-7, which did inhibit TPA-induced T cell attachment to fibronectin. Monoclonal antibodies against both the alpha 5 and the beta 1 subunits of the classical fibronectin receptor as well as an Arg-Gly-Asp (RGD) peptide inhibited attachment, whereas anti-alpha 4 monoclonal antibodies and the CS1 peptide did not. Binding to collagen IV was also inhibited by the anti-beta 1 monoclonal antibody, but not the other antibodies. Cells metabolically labeled with [35S]methionine and analyzed by immunoprecipitation with polyclonal anti-beta 1 integrin antibody showed a 2.5-fold increase in integrin synthesis in infected cells compared to uninfected controls. This increase in synthesis was associated with an increase in cell surface expression of both alpha 5 and beta 1 integrins by FACS (registered trademark of Becton Dickinson for a fluorescence-activated cell sorter) analysis. Enhanced expression of integrins such as alpha 5 beta 1 may cause T cell adherence to a variety of tissues, where released viral gene products may induce some of the tissue-specific manifestations of HIV-1 infection.
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PMID:HIV-1 infection of human T lymphocytes results in enhanced alpha 5 beta 1 integrin expression. 183 Dec 4

Automated N-terminal microsequencing of immune affinity-purified acquired immunodeficiency syndrome retrovirus polypeptides from infected cells was used to locate the N termini of 64-, 51-, and 34-kilodalton (kDa) polypeptides within the pol open reading frame (ORF) of the proviral DNA. The 64- and 51-kDa proteins had identical N termini (Pro-Ile-Ser-Pro-IIe-Glu-Thr-Val-) positioned 156 residues from the beginning of the pol ORF. The N terminus of the 34-kDa pol gene product, Phe-Leu-Asp-Gly-Ile-Asp-Lys-, mapped 716 residues into the pol ORF. These polypeptides were absent in an RT-negative, CD4-negative, persistently infected cell line (8E5) carrying a single defective copy of a constitutively expressed, integrated proviral DNA.
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PMID:Structural characterization of reverse transcriptase and endonuclease polypeptides of the acquired immunodeficiency syndrome retrovirus. 243 Jan 11

A synthetic peptide (SP-10-IIIB) with an amino acid sequence [Cys-Thr-Arg-Pro-Asn-Asn-Asn-Thr-Arg-Lys-Ser-Ile-Arg-Ile-Gln-Arg-Gly-Pro -Pro-Gly-(Tyr); amino acids 303-321] from the human immunodeficiency virus (HIV) isolate human T-cell lymphotropic virus type III (HTLV-III) HTLV-IIIB envelope glycoprotein gp120 was coupled to tetanus toxoid and used to raise goat antibodies to HIV gp120. Goat anti-SP-10-IIIB serum bound to the surface of HTLV-IIIB-infected CEM T cells but not to the surface of HTLV-IIIRF-infected or uninfected CEM T cells. Anti-SP-10-IIIB antibodies also selectively bound to gp120 from lysates of HTLV-IIIB cells in immunoblot assays. Twenty-one percent of sera (28 of 175) from patients seropositive for HIV contained antibodies that reacted with SP-10-IIIB in RIA. Human anti-SP-10-IIIB antibodies affinity purified from acquired immunodeficiency syndrome (AIDS) patient serum bound to HTLV-IIIB-infected cells and immunoprecipitated gp120. Goat antibodies to SP-10-IIIB neutralized HTLV-IIIB (80% neutralization titer of 1/600), inhibited HTLV-IIIB-induced syncytium formation, but did not neutralize HIV isolates HTLV-IIIRF or HTLV-IIIMN or inhibit syncytium formation with these isolates. Also, goat antiserum to an homologous synthetic peptide [SP-10-IIIRF(A), (Cys)-Arg-Lys-Ser-Ile-Thr-Lys-Gly-Pro-Gly-Arg-Val-Ile-Tyr] from gp120 of HIV isolate HTLV-IIIRF inhibited syncytium formation by HTLV-IIIRF, but did not inhibit syncytium formation by HTLV-IIIB or by HTLV-IIIMN. Thus, the amino acid sequences of SP-10-IIIB and SP-10-IIIRF(A) define homologous regions of gp120 that are important in type-specific virus neutralization. The identification of these type-specific neutralizing epitopes should facilitate the design of a polyvalent, synthetic vaccine for AIDS.
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PMID:Type-specific neutralization of the human immunodeficiency virus with antibodies to env-encoded synthetic peptides. 245 Mar 51

Infection by molecularly cloned HIV-1, in the presence of a high-titre neutralizing monoclonal antibody (MAb), resulted in the selection of plaques in MT4 cells releasing HIV resistant to neutralization by the same MAb. The epitope recognized by the MAb was mapped to the V3 neutralization epitope at amino acids 305-321. The HIV-1 variants showed a reduced binding capacity for the selecting MAb as determined by immunofluorescence. Polymerase chain reaction (PCR) amplification of complementary DNA derived from viral RNA, cloning and sequencing identified a base pair (bp) change C----G at position 6663 in variant 110.5/1, predicting a change at amino acid 308 Arg----Gly. No other changes in the epitope were observed by sequencing three other variants. Differential hybridization of PCR amplified viral RNA and DNA, with oligonucleotides specific for the observed bp change or the 'wild type' sequence, indicated that the variants 110.5/1 and 110.5/7 were genotypically mixed for 308Gly/Arg. Subsequent screening of biologically 'recloned' variants 110.5/1 and 110.5/7 identified two subclones homozygous for the 308Gly change. The Arg----Gly change appears to affect the binding of the antibody to the epitope, since the linear peptide substituting 308Gly for 'wild type' 308Arg was 100 times less potent in blocking the neutralization of parental HIV. Amino-acid residue 308 thus appears to be crucial for antibody binding to the epitope. In addition, mutations distant from the monoclonal antibody binding site may also affect neutralization by antibodies recognizing the V3 loop.
AIDS 1989 Dec
PMID:Characterization of HIV-1 neutralization escape mutants. 248 18

Knowledge of the tertiary structure of the proteinase from human immunodeficiency virus HIV-1 is important to the design of inhibitors that might possess antiviral activity and thus be useful in the treatment of AIDS. The conserved Asp-Thr/Ser-Gly sequence in retroviral proteinases suggests that they exist as dimers similar to the ancestor proposed for the pepsins. Although this has been confirmed by X-ray analyses of Rous sarcoma virus and HIV-1 proteinases, these structures have overall folds that are similar to each other only where they are also similar to the pepsins. We now report a further X-ray analysis of a recombinant HIV-1 proteinase at 2.7 A resolution. The polypeptide chain adopts a fold in which the N- and C-terminal strands are organized together in a four-stranded beta-sheet. A helix precedes the single C-terminal strand, as in the Rous sarcoma virus proteinase and also in a synthetic HIV-1 proteinase, in which the cysteines have been replaced by alpha-aminobuytric acid. The structure reported here provides an explanation for the amino acid invariance amongst retroviral proteinases, but differs from that reported earlier in some residues that are candidates for substrate interactions at P3, and in the mode of intramolecular cleavage during processing of the polyprotein.
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PMID:X-ray analysis of HIV-1 proteinase at 2.7 A resolution confirms structural homology among retroviral enzymes. 268 66

In human lymphocytes three dipeptidyl peptidases were discovered in our laboratory. For a correct demonstration of activities of these enzymes discriminating substrates must be used. Dipeptidyl peptidase IV (DPP IV) is revealed with Gly-Pro-4-methoxy-2-naphthylamide (Gly-Pro-MNA) and Fast Blue B (FBB). It is present in the surface membrane of about 40% lymphocytes of the peripheral blood. Only T-lymphocytes bear the reaction. Reacting lymphocytes belong predominantly to OKT4+ subset. Some OKT8+ lymphocytes also react. With more sensitive substrates (Lys-Pro-MNA, Phe-Pro-MNA and Ala-Pro-MNA) a co-reaction of DPP II was demonstrated "in situ" and in zymograms. In haemoblastoses a positive reaction in cells indicates their derivation from the T-lineage of lymphocytes. A negative reaction does not exclude a T-cell malignancy, however. A decreased number of DPP IV positive lymphocytes in the peripheral blood indicates a diminished immunocompetent potential of T-cells, e.g. immunodeficiency in patients with malignant lymphoma, gastric and colocrectal carcinoma, AIDS, etc. DPP II demonstrated with Lys-Ala-MNA occurs in about 60% of lymphocytes belonging to T and B subsets. It is localized in lysosomes. Although Lys-Pro-MNA is a more sensitive substrate a co-reaction of DPP IV must always be considered. Patients with chronic B-lymphocytic leukaemia displaying a high number of DPP II+ cells usually have a worse prognosis. DPP I assessed with Gly-Pro-MNA and nitrosalicylaldehyde occurs in about 20% of T and B lymphocytes. The number of positively reacting cells increases after corticosteroid therapy. The influence of the treatment on the activity can be shown very well in histograms of DPP I activity measured by computer-assisted microfluorometry.
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PMID:Dipeptidyl peptidases of human lymphocytes. 290 80

The core of the fibronectin cell-attachment site has been shown to be the tetrapeptide sequence Arg-Gly-Asp-Ser (RGDS). This peptide as well as its inverted analogue Ser-Asp-Gly-Arg (SDGR) efficiently inhibit fibronectin-mediated cell attachment in vivo and in vitro. Homology searches in protein data banks revealed the presence of the peptide SDGR in the alpha 2 domain of MHC class I antigens, and a variant of RGDS, Arg-Phe-Asp-Ser (RFDS), was found highly conserved in MHC class I (alpha 1 domain) and class II antigens (beta 1 domain). Three-dimensional models of MHC class I antigens suggested that the two tetrapeptide sequences may be located at the surface of the molecule, readily available for intermolecular contacts. We propose that fibronectin-mediated and MHC-mediated cell-cell interactions have similar molecular bases and that the RGDS-like sequences participate in specific cell adhesion between lymphoid cells. The RFDS tetrapeptide was also found in the sequence of a putative polypeptide chain encoded by the HTLVIII/LAV retrovirus family, the causative agent of AIDS. These amino acid sequence homologies suggest a common molecular basis for specific interactions between the MHC class II antigens, or the AIDS virus, and the T -cell specific T4 glycoprotein.
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PMID:Speculations on sequence homologies between the fibronectin cell-attachment site, major histocompatibility antigens, and a putative AIDS virus polypeptide. 300 64


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