| association of antibodies blocking hiv-1 gp 160-scd4 attachment with virus neutralizing activity in human sera. | sera, from hiv-1 and hiv-2 seropositive individuals, were tested for the presence of antibodies able to inhibit the binding (bi) of hiv-iiib gp 160 (produced in mammalian cells using a vaccinia expression system) to the extracellular portion of the cd4 receptor. a competition enzyme immunoassay (eia) with soluble cd4 (scd4) was used. bi antibodies were highly prevalent among hiv-1 seropositives but not in hiv-2 infected individuals. attempts to localize the binding site for these bi antibodies o ... | 1990 | 1697332 |
| [diagnosis of hepatitis c virus (hcv) infection: diagnostic value of the anti-hcv test]. | different groups of patients were analysed for antibody to hepatitis-c-virus (anti-hcv). a high prevalence was found in individuals with parenteral exposure (chronic non-a, non-b hepatitis, 77.5%, drug addicts 84.5%), while blood donors had a prevalence of 0.51%, this was significantly higher in patients with chronic type b hepatitis (30%), in homosexuals (22.5%) and in patients with different types of autoimmune hepatitis (57.2%). this indicates that differential diagnosis of chronic hepatitis ... | 1990 | 1698329 |
| characterization of the human immunodeficiency virus type-1 reverse transcriptase enzyme produced in yeast. | the reverse transcriptase (rt) of human immunodeficiency virus type-1 (hiv-1) is comprised of two subunits of approximately 66kd and 51kd. we have defined the carboxyl terminus of the 51kd molecule using the 66kd rt and hiv-1 protease (pr) expressed in yeast. precise constructs encoding the 66kd and 51kd molecules were expressed individually, in yeast, at high levels. the purified recombinant subunits were shown to associate into heterodimers that retained both rt and rnase h activities. only th ... | 1990 | 1698361 |
| synthetic peptides containing t and b cell epitopes from human immunodeficiency virus envelope gp120 induce anti-hiv proliferative responses and high titers of neutralizing antibodies in rhesus monkeys. | we have previously described a synthetic peptide (t1-sp10) derived from two noncontiguous regions of htlviiib envelope gp120 (t1, amino acids 428-443; sp10, amino acids 303-321) that induced type-specific anti-hiv neutralizing antibodies and t cell proliferative responses against native hiv gp120 when used as a carrier-free immunogen in goats. in this study, htlviiib t1-sp10 synthetic peptides were used to immunize rhesus monkeys to determine if the peptides were capable of eliciting hiv-specifi ... | 1990 | 1698859 |
| overproduction of human immunodeficiency virus type i reverse transcriptase in escherichia coli and purification of the enzyme. | overexpression of the reverse transcriptase was designed in e. coli. for a high level of expression, hiv protein was expressed as a protein fusion with beta-galactosidase. when the proviral dna fragment covering the 3' half of the gag gene and the entire pol gene was ligated to the 3' end of the lacz gene to fuse the truncated gag to lacz in frame, a small quantity of reverse transcriptase was produced, indicating that frameshifting and post-translational processing have occurred. much more reve ... | 1990 | 1699113 |
| direct comparisons of inhibitor sensitivities of reverse transcriptases from feline and human immunodeficiency viruses. | the sensitivities of reverse transcriptases (rts) from feline immunodeficiency virus (fiv) and human immunodeficiency virus type 1 (hiv) were directly compared. the two enzymes had similar sensitivities to three analogs of dttp, namely, 3'-azido-3'-deoxythymidine 5'-triphosphate, 2',3'-dideoxythymidine 5'-triphosphate, and 2',3'-dideoxy-2',3'-didehydrothymidine 5'-triphosphate. each of these analogs demonstrated competitive inhibition of both enzymes. ki values for inhibition of fiv rt by these ... | 1990 | 1699491 |
| [application of sensitive reverse transcriptase assay to human immunodeficiency virus (hiv) type 2]. | sensitive reverse transcriptase assay was applied to human immunodeficiency virus type 2. the kinetics of this assay, stability of the enzyme and the effect of bsa to this assay indicated that the condition of this assay should be 37 degrees c in reaction temperature. the sensitivity of this assay increased by adding more than 10 micrograms/ml of bsa. the sensitivity of this assay is at least four times more than that of cpe assay using molt-4 cell. other hiv-2 isolate, lav-2 in culture medium w ... | 1990 | 1700034 |
| comparative studies on tat mutants of three primate lentiviruses. | a frame-shift tat gene mutant of human immunodeficiency virus type 1 (hiv-1), which showed no detectable trans-activation potential, was constructed in vitro. upon transfection, this clone directed the synthesis of virus mrnas, gag proteins and virion-associated reverse transcriptase (rt) at a low level as was observed with the tat mutants of hiv-2 and simian immunodeficiency virus isolated from african green monkey (sivagm). using these mutant viruses, trans-activation efficiency of viral gene ... | 1990 | 1700693 |
| functional comparison of transactivation by human retrovirus rev and rex genes. | the effect of rev-responsive element deletion on human immunodeficiency virus type 1 (hiv-1) and type 2 (hiv-2) gene expression was examined. the phenotypes of hiv-1 and hiv-2 provirus dnas lacking the rev-responsive element, as determined by transfection experiments, were indistinguishable from those of virus dnas carrying rev gene mutations. by using rev-response elements derived from these two viruses, we developed two monitoring systems to evaluate the functionality of hiv-1 rev, hiv-2 rev, ... | 1990 | 1700826 |
| soluble cd4 enhances simian immunodeficiency virus sivagm infection. | the cd4 molecule is expressed on t-helper cells and serves as the cellular receptor for the human immunodeficiency virus types 1 and 2 (hiv-1 and hiv-2) and for the simian immunodeficiency viruses sivmac and sivagm. hiv-1, hiv-2, and sivmac infectivity can be blocked by monoclonal antibodies (mabs) directed against the cd4 molecule and by soluble cd4 proteins (scd4). in the present study, we demonstrated not only lack of inhibition, but 10- to 100-fold scd4-dependent enhancement of sivagm infect ... | 1990 | 1700834 |
| no t-cell tyrosine protein kinase signalling or calcium mobilization after cd4 association with hiv-1 or hiv-1 gp120. | the t lymphocyte surface protein cd4 is an integral membrane glycoprotein noncovalently associated with the tyrosine protein kinase p56lck. in normal t cells, surface association of cd4 molecules with other cd4 molecules or other t-cell surface proteins, such as the t-cell antigen receptor, stimulates the activity of the p56lck tyrosine kinase, resulting in the phosphorylation of various cellular proteins at tyrosine residues. thus, the signal transduction in t cells generated through the surfac ... | 1990 | 1701034 |
| search for epitope-specific antibody responses to the human immunodeficiency virus (hiv-1) envelope glycoproteins signifying resistance to disease development. | it is essential for the development of strategies for prevention and therapy of human immunodeficiency virus (hiv-1) infections to define host factors playing a dominant role in determining the clinical outcome of infection. antibodies directed against restricted regions of the hiv-1 glycoproteins gp120 and gp41 are likely to represent important factors involved in host defense against hiv-1. definition of qualitative and quantitative differences in the spectrum of anti-gp120 and anti-gp41 antib ... | 1990 | 1701315 |
| [the enhancement of the penetration of the human immunodeficiency virus into cells with the aid of a helper virus]. | penetration of human immunodeficiency virus (hiv) into the cells of lymphoblastoid t-cell line h9 was studied using 35s-methionine-labeled virus by demonstration of virus-specific proteins in the cytoplasm of the infected cells. purification of the virus by ultracentrifugation through 30% glycerol was shown to lead to virus aggregation and its partial destruction manifested by the loss of gp120 protein, therefore unlabeled concentrated virus was used mainly with subsequent determination of virus ... | 1990 | 1701589 |
| mutational analysis of the dna polymerase and ribonuclease h activities of human immunodeficiency virus type 2 reverse transcriptase expressed in escherichia coli. | we have constructed a plasmid that, when introduced into escherichia coli, induces the synthesis of large quantities of a polypeptide with an apparent molecular weight of 68 kda. the hiv-2 reverse transcriptase (rt) made in e. coli is soluble in bacterial extracts and possesses both rna-dependent dna polymerase and ribonuclease h (rnase h) activities typical of retroviral rts. the hiv-2 rt expression clone was used to generate mutations in hiv-2 rt. there is a strong correlation between the effe ... | 1991 | 1701948 |
| attenuation of human immunodeficiency virus type 1 cytopathic effect by a mutation affecting the transmembrane envelope glycoprotein. | the cytopathic effects of human immunodeficiency virus type 1 (hiv-1) infection are specific for cells that express the cd4 viral receptor and consist of syncytium formation and single-cell lysis. here we report that a mutation (517a) affecting the amino terminus of the hiv-1 gp41 transmembrane envelope glycoprotein resulted in a virus that was markedly less cytopathic than was wild-type hiv-1. in systems in which cell-to-cell transmission of hiv-1 occurred, the replication ability of the 517a v ... | 1991 | 1702159 |
| anti-fas monoclonal antibody is cytocidal to human immunodeficiency virus-infected cells without augmenting viral replication. | a cytotoxic monoclonal antibody (anti-fas mab) against the 200-kda cell surface fas antigen, which is associated with the tumor necrosis factor (tnf) receptor, was examined for its in vitro activity on human immunodeficiency virus (hiv)-infected cells. it was found that both tnf and anti-fas mab selectively killed the chronically hiv-infected cells. uninfected cells were less sensitive to the antibody than those infected with hiv. when the cells were cultured in the presence of anti-fas mab imme ... | 1990 | 1702216 |
| immunogenicity of the human immunodeficiency virus (hiv) recombinant nef gene product. mapping of t-cell and b-cell epitopes in immunized chimpanzees. | the nonstructural nef gene product of human immunodeficiency virus (hiv), p27, is a regulatory "early phase" protein produced by hiv-infected cells. as a possible negative regulator of transcription, it has been suggested that p27 may be involved in the control of hiv proviral latency. immune reactivity to p27 may result in early destruction of hiv-replicating cells before viral assembly or of latently infected cells. it appeared, thus, of interest to investigate the immunogenicity of the molecu ... | 1990 | 1702299 |
| reverse transcriptase.rnase h from the human immunodeficiency virus. relationship of the dna polymerase and rna hydrolysis activities. | human immunodeficiency virus reverse transcriptase.rnase h (rt.rnase h) has an rna hydrolysis specificity which was influenced both by the sequence of the dna primer-rna template and by binding of the polymerase active site to the primer 3' terminus. rt.rnase h selectively hydrolyzed the phosphodiester bond between the 15th and 16th ribonucleotide back from the ribonucleotide that is complementary to the primer 3'-terminal deoxynucleotide. the cleavage site for rt.rnase h remained a fixed distan ... | 1991 | 1702425 |
| the integrity of the stem structure of human immunodeficiency virus type 1 tat-responsive sequence of rna is required for interaction with the interferon-induced 68,000-mr protein kinase. | a number of eucaryotic viruses have devised strategies to minimize the deleterious effects on protein synthesis caused by activation of the interferon-induced, double-stranded-rna-activated protein kinase, p68. in a recent report, we described the down regulation of the p68 protein kinase in cells infected by human immunodeficiency virus type 1 (hiv-1) (s. roy, m. g. katze, n. t. parkin, i. edery, a. g. hovanessian, and n. sonenberg, science 247:1216-1219, (1990). we now present evidence that su ... | 1991 | 1702840 |
| psychosocial aspects of aids in children and adolescents. | the first part of this article addresses the neuropsychiatric aspects of human immunodeficiency virus (hiv) infection in children and adolescents, including developmental delay, depression, and dementia. the specific clinical issues of disclosure of diagnosis and discussion of death with a child are examined. the second part presents aspects of the impact of aids on families, approaches to hiv antibody testing, and therapeutic interventions for the family. | 1991 | 1702886 |
| cross-reactivity with sivmac in east african hiv-1-positive sera: evidence against double infection with hiv-1 and a sivmac/hiv-2-like virus. | igg antibodies reactive with simian immunodeficiency virus isolated from a rhesus monkey suffering from simian acquired immunodeficiency syndrome (sivmac, strain 239, a virus which is very closely related to human immunodeficiency virus type 2-hiv-2) were found in 18 of 120 swedish and 8 of 11 east african confirmed hiv-1 antibody positive (hiv-1 ab+) sera, both by enzyme immunoassay and electrophoretic immunoblotting (p = 1 x 10(-6). in electrophoretic immunoblotting most of the cross-reactivit ... | 1990 | 1703133 |
| contribution of multiple rounds of viral entry and reverse transcription to expression of human immunodeficiency virus type 1. a quantitative kinetic study. | human immunodeficiency virus 1 (hiv-1) infection in vitro has been analyzed by the kinetics of expression of hiv-1 rna and antigens during treatment with antiviral agents. intracellular hiv-1 rna rose from input values of 15 molecules per cell to 28 molecules per cell within 3 h after infection and reached a peak of 13,125 in 5 days. the first detectable increase in levels of hiv-1 capsid protein production was 1 day after infection. virus infection was interrupted at different time points by th ... | 1991 | 1703155 |
| glycosylation governs the binding of antipeptide antibodies to regions of hypervariable amino acid sequence within recombinant gp120 of human immunodeficiency virus type 1. | antibodies raised to an overlapping series of peptides following the amino acid sequence of the external envelope glycoprotein (gp 120) of human immunodeficiency virus type 1 (hiv-1) recognize eight regions in recombinant gp 120 molecules. if the recombinant molecules are glycosylated, three of these regions show a reduced capacity to bind antibody. of the other five regions, two are strain-specific and carbohydrate restricts antibody binding to their n-terminal flanks, and three can be recogniz ... | 1990 | 1703212 |
| many crystal forms of human immunodeficiency virus reverse transcriptase. | many crystal forms of human immunodeficiency virus reverse transcriptase have been obtained by vapour diffusion, microbatch and microdialysis methods. despite their apparent morphological perfection, no x-ray diffraction has been discernible in most cases with these crystals. | 1991 | 1703235 |
| characterization of monoclonal antibodies directed against distinct conserved epitopes of human immunodeficiency virus type 1 core proteins. | two mouse hybridoma cell lines secreting antibodies to the human immunodeficiency virus (hiv) p25 major core protein and its precursors p55 and p41, were developed after immunization with the highly cytopathic zaïrian hiv-1 isolate, ndk. these monoclonal antibodies also react with the gag gene products from hiv-1-bru prototype and present cross reaction with hiv-2-rod, and siv-agm. they map into topographically distinct areas of p25 and define epitopic regions topographically separated from thos ... | 1990 | 1703272 |
| monoclonal idiotypic and anti-idiotypic antibodies to human immunodeficiency virus type 1 envelope glycoprotein. | murine monoclonal antibodies (mabs) gp41-1 (igg2a) and gp41-2 (igg1), directed against the envelope glycoprotein of human immunodeficiency virus type 1 (hiv-1), were produced and characterized. these mabs recognized both gp160 and gp41 and reacted with divergent hiv-1 isolates. surface binding assays using viable hiv-infected cells indicated that these mabs were directed against surface-exposed epitopes. both mabs caused a reduction in reverse transcriptase activity. syngeneic monoclonal antiidi ... | 1991 | 1703562 |
| map of sequential b cell epitopes of the hiv-1 transmembrane protein using human antibodies as probe. | antibodies of individuals infected with the human immunodeficiency virus type 1 (hiv-1) were used to probe the antigenicity of the hiv-1 transmembrane protein of 41 kd (gp41) by antibody-reactive peptide scanning (pepscan). eleven distinct sequential antibody-binding sites were defined by testing reactivity to 339 overlapping nonapeptides spanning the complete gp41 amino acid sequence. such analysis only maps continuous antibody-binding sites of nine amino acids in length and does not identify p ... | 1990 | 1704000 |
| common immunologic determinant between human immunodeficiency virus type 1 gp41 and astrocytes. | monoclonal antibodies against a synthetic 12-amino-acid peptide that comprises the immunodominant domain of human immunodeficiency virus type 1 gp41 (amino acids 598 through 609) reacted with astrocytes found in human and rodent central nervous system tissue. the monoclonal antibodies bound to a 43-kda protein found in central nervous system tissue preparations. these results indicate that human immunodeficiency virus type 1 gp41 contains a common epitope with astrocytes and that an immune respo ... | 1991 | 1704927 |
| reconstitution in vitro of rnase h activity by using purified n-terminal and c-terminal domains of human immunodeficiency virus type 1 reverse transcriptase. | two constituent protein domains of human immunodeficiency virus type 1 (hiv-1) reverse transcriptase were expressed separately and purified to homogeneity. the n-terminal domain (p51) behaves as a monomeric protein exhibiting salt-sensitive dna polymerase activity. the c-terminal domain (p15) on its own has no detectable rnase h activity. however, the combination of both isolated p51 and p15 in vitro leads to reconstitution of rnase h activity on a defined substrate. these results demonstrate th ... | 1991 | 1705027 |
| an antiviral target on reverse transcriptase of human immunodeficiency virus type 1 revealed by tetrahydroimidazo-[4,5,1-jk] [1,4]benzodiazepin-2 (1h)-one and -thione derivatives. | screening of pharmacologically acceptable prototype compounds has recently led to the discovery of a series of ultraselective inhibitors of human immunodeficiency virus (hiv)-1 replication, the tetrahydroimidazo[4,5,1-jk] [1,4]-benzodiazepin-2(1h)-one and -thione (tibo) derivatives. the tibo compounds completely suppress the formation of proviral dna in acutely infected cells, as revealed by polymerase chain reaction (pcr) analysis. tibo derivatives are inhibitory to the reverse transcriptase (r ... | 1991 | 1705038 |
| [analysis of receptor expression on astrocytic cells]. | astrocytes are regarded as matrix of the neuron in central nervous system (cns) and involve nutritional and supporting function of neuron. it was clarified that human and murine cultured astrocytes had fc receptor (fcr) on their cell surface from the study of ea rosette assay, reverse adcc (antibody dependent cellular cytotoxicity) and flow cytometric analysis with anti-fcr monoclonal antibodies (mab) in this study. human glioma cells express fcr iii recognized by mab mg 12 and mouse astrocytes ... | 1990 | 1705127 |
| enhancement of hiv-1 cytocidal effects in cd4+ lymphocytes by the aids-associated mycoplasma. | coinfection with mycoplasma fermentans (incognitus strain) enhances the ability of human immunodeficiency virus type-1 (hiv-1) to induce cytopathic effects on human t lymphocytes in vitro. syncytium formation of hiv-infected t cells was essentially eliminated in the presence of m. fermentans (incognitus strain), despite prominent cell death. however, replication and production of hiv-1 particles continued during the coinfection. furthermore, the supernatant from cultures coinfected with hiv-1 an ... | 1991 | 1705362 |
| strain-specific neutralizing determinant in the transmembrane protein of simian immunodeficiency virus. | monoclonal antibody sf8/5e11, which recognizes the transmembrane protein (tmp) of simian immunodeficiency virus of macaque monkeys (sivmac), displayed strict strain specificity. it reacted with cloned and uncloned sivmac251 but not with cloned sivmac142 and sivmac239 on immunoblots. this monoclonal antibody neutralized infection by cloned, cell-free sivmac251 and inhibited formation of syncytia by cloned sivmac251-infected cells; these activities were specific to cloned sivmac251 and did not occ ... | 1991 | 1705994 |
| human transformed trophoblast-derived cells lacking cd4 receptor exhibit restricted permissiveness for human immunodeficiency virus type 1. | we investigated the nature of interaction of the malignantly transformed cell lines of trophoblast origin bewo, jar, and jeg-3 with three different human immunodeficiency virus type 1 (hiv-1) isolates (rf, 3b, and ndk). after inoculation with cell-free virus, the persistence of infection was determined for 1 month by monitoring the presence of viral dna in the cells by the polymerase chain reaction (pcr). furthermore, the infectious virus in the culture supernatant was assayed with cem-ss cells, ... | 1991 | 1705998 |
| potent and selective inhibition of human immunodeficiency virus type 1 (hiv-1) by 5-ethyl-6-phenylthiouracil derivatives through their interaction with the hiv-1 reverse transcriptase. | in the search for 1-[(2-hydroxyethoxy)-methyl]-6-(phenylthio)thymine (hept) derivatives, we have found several 5-ethyl-6-(phenylthio)uracil analogues to be highly potent and selective inhibitors of human immunodeficiency virus (hiv) type 1. 1-benzyloxymethyl-5-ethyl-6-phenylthiouracil, the most potent congener of the series, inhibits hiv-1 replication in a variety of cell systems, including peripheral blood lymphocytes, at a concentration of 1.5-7.0 nm, which is lower by a factor of 10(3) than t ... | 1991 | 1706522 |
| antiretroviral activity, biochemistry, and pharmacokinetics of 3'-azido-2',3'-dideoxy-5-methylcytidine. | 3'-azido-2',3'-dideoxy-5-methylcytidine (cs-92, azddmec) is an antiviral nucleoside analogue structurally related to 3'-azido-3'-deoxythymidine (azt). cs-92 is a potent and selective inhibitor of hiv-1 reverse transcriptase and hiv-1 replication in human lymphocytes and macrophages. the ec50 for cs-92 in hiv-1-infected human pbm cells was 0.09 microm. in hiv-1-infected human macrophages, the ec50 was 0.006 microm. this compound was also effective against human immunodeficiency virus type 2 in ly ... | 1990 | 1706574 |
| generation and characterization of the human immunodeficiency virus type 1 mutants. | mutations were introduced by recombinant dna techniques into 9 genes of an infectious molecular clone of human immunodeficiency virus type 1. the 24 mutants generated were characterized biochemically and biologically by transfection and infection experiments. none of the mutants which have mutations in gag (p17, p24, and p15 regions), pol (protease, reverse transcriptase, and endonuclease domains), env (gp120 region), tat, or rev were infectious, whereas vif, vpr, vpu, some of env (gp41) and nef ... | 1991 | 1706590 |
| siv, stlv-i and type d retrovirus antibodies in captive rhesus macaques and immunoblot reactivity to siv p27 in human and rhesus monkey sera. | the prevalence of simian immunodeficiency virus (siv), simian t-cell lymphotropic virus type 1 (stlv-i), and type d retrovirus (srv-d) antibodies was determined for 1229 rhesus monkeys (macaca mulatta) from two research colonies. serum samples were tested by using enzyme-linked immunosorbent assay (elisa), immunoblot (ib), and radioimmunoprecipitation assay (ripa). seropositive results for the three retroviruses tested were 0 for siv, 270 (22%) for stlv-i, and 103 (8.4%) for type d retrovirus. o ... | 1990 | 1706606 |
| characterization of serum antibody responses to recombinant hiv-1 gp160 vaccine by enzyme immunoassay. niaid aids vaccine clinical trials network. | an enzyme immunoassay (eia) was developed to measure serum antibody responses of healthy adult volunteers vaccinated with 40 or 80 micrograms of human immunodeficiency virus type 1 (hiv-1) recombinant gp160 (rgp160) vaccine at 0, 1, 6, and 18 months. this assay, which used purified rgp160 as antigen, was compared with the biotech/du pont hiv-1 western blot and the abbott hiv-1 eia. of 33 volunteers who received three doses of rgp160 vaccine, seroresponses were detected in 91% by rgp160 eia, 97% ... | 1990 | 1706607 |
| a capture enzyme immunoassay for detection of hiv-2/siv antigen. | an antigen capture enzyme immunoassay was developed for the demonstration of human immunodeficiency virus type 2 (hiv-2) and simian immunodeficiency virus (siv). the assay (hiv-2 ce) has a sensitivity of approximately 250 pg/ml of hiv-2/siv antigen. the hiv-2 ce was 4-16 times more sensitive than the abbott hiv-1 antigen assay for detection of hiv-2/siv antigen in cell culture supernatant. the sensitivity for detection of hiv-2/siv antigen in serum or plasma was 98.5% in the hiv-2 ce and 95.5% i ... | 1991 | 1706769 |
| human immunodeficiency virus type-1 infection of homosexual men is accompanied by a decrease in circulating b cells. | as part of the multidisciplinary effort to characterize the natural history of human immunodeficiency virus type 1 (hiv-1) infection, the cell-surface phenotypes of lymphocytes from a cohort of homosexual men were analyzed in detail and related to clinical and laboratory parameters associated with hiv-1 infection. the present study represents a cross-sectional analysis of coded specimens from 153 homosexual men, of whom 74 were seronegative and 79 seropositive for hiv-1. fewer circulating b lymp ... | 1991 | 1706770 |
| foscarnet. a review of its antiviral activity, pharmacokinetic properties and therapeutic use in immunocompromised patients with cytomegalovirus retinitis. | the pyrophosphate analogue, foscarnet, selectively inhibits the dna polymerase of human herpes viruses, including cytomegalovirus, and the reverse transcriptase of hiv. viral replication is therefore prevented, but resumes when the drug is cleared from infected cells. in vitro, the combination of foscarnet and zidovudine (azidothymidine) has an additive effect against cytomegalovirus and acts synergistically against hiv. an improvement in cytomegalovirus retinitis is obtained in over 85% of affe ... | 1991 | 1706982 |
| re-evaluation of the involvement of the adhesion molecules icam-1/lfa-1 in syncytia formation of hiv-1-infected subclones of a cem t-cell leukemic line. | the role of the adhesion molecules intercellular adhesion molecule-1 (icam-1) and lfa-1 in human immunodeficiency virus type 1 (hiv-1)-induced cell fusion was investigated in subclones of a t-cell leukemic cell line (cem) with differing abilities to form syncytia. addition of monoclonal antibodies 84h10 directed against icam-1 and mhm23 directed against the common beta subunit of lfa-1 (cd18) resulted in greater than 50% suppression of syncytia formation in cultures of these clones infected with ... | 1991 | 1707641 |
| monoclonal antibodies to conserved regions of the major core protein (gag24) of hiv-1 and hiv-2. | five mouse monoclonal antibodies were raised against a recombinant protein comprising the complete sequence of gag24 protein from htlv-iiib. all monoclonal antibodies recognized the native protein in enzyme-linked immunosorbant assay (elisa) and western blots. all monoclonal antibodies also cross-reacted with an human immunodeficiency virus type 2 (hiv-2) strain in western blots, whereas only one antibody detected hiv-2 p25 in elisa. by using synthetic peptides, cross-reacting epitopes were mapp ... | 1991 | 1707645 |
| pentoxifylline (trental) decreases the replication of the human immunodeficiency virus type 1 in human peripheral blood mononuclear cells and in cultured t cells. | pentoxifylline (trental), used routinely for the treatment of intermittent claudication, has been shown previously to decrease the levels of tumor necrosis factors-alpha (tnf-alpha) rna in cancer patients and to lead to a general improvement of well being. increased tnf-alpha levels have been observed not only in cancer patients but also in cachectic patients with the acquired immunodeficiency syndrome (aids), and tnf-alpha is known to increase the expression of the human immunodeficiency virus ... | 1991 | 1707692 |
| interaction of c-terminal sequences of human immunodeficiency virus reverse transcriptase with template primer. | we have raised a rabbit monospecific antibody (designated c2003) against a synthetic peptide (ctp66) derived from a conserved sequence in the c-terminal portion of the p66 component of human immunodeficiency virus type 1 (hiv-1) reverse transcriptase (rt) (devico, a.l., copeland, t.d., veronese, f.d., oroszlan, s., gallo, r. c., and sarngadharan, m. g. (1989) aids res. hum. retroviruses 5, 51-60). this antibody directly inhibits the polymerase activity of hiv-1 rt and of rts from a variety of re ... | 1991 | 1707875 |
| inhibition of hiv replication in lymphocyte cultures of virus-positive subjects in the presence of sho-saiko-to, an oriental plant extract. | an oriental remedy, sho-saiko-to (sst) consisting of a mixture of aqueous extracts from seven different plants and whose most active component is the chemically defined compound baicalein was tested for its ability to inhibit the production of the human immunodeficiency virus (hiv). the testing was done with cultures of human lymphocytes obtained from hiv-positive asymptomatic subjects and patients with arc or aids. the replication of the virus was monitored by quantitative assay of the reverse ... | 1990 | 1708225 |
| epitopes of human immunodeficiency virus type 1 (hiv-1) envelope glycoproteins recognized by antibodies in the sera of hiv-1-infected individuals. | sera from human immunodeficiency virus (hiv)-infected study subjects and controls were analyzed by enzyme-linked immunosorbent assay using 10 synthetic peptides to identify epitopes of hiv envelope glycoproteins (envgp) that were recognized by antibodies. two epitopes of hiv envgp, envp466 (amino acids 466-481) and envp497 (amino acids 497-509), were recognized by antibodies in the sera of most hiv-infected individuals. the frequency of individuals with detectable serum antibodies to these two e ... | 1991 | 1708316 |
| antibodies to recombinant hiv-1 nef protein detected in hiv-1 infection as well as in nonrisk individuals. | | 1990 | 1708319 |
| inhibition of human immunodeficiency virus type 1 (hiv-1) replication by the dipyridodiazepinone bi-rg-587. | the dipyridodiazepinone human immunodeficiency virus type 1 (hiv-1)-specific reverse transcriptase (rt) inhibitor bi-rg-587 was tested for its ability to inhibit hiv-1 replication in both acutely and chronically infected cell lines. the ability of bi-rg-587 to inhibit steps in the virus replicative cycle other than reverse transcription was also assessed. bi-rg-587 was found to be a potent inhibitor of hiv-1 replication in acutely infected cells (50% inhibitory concentration [ic50] = 37.2 nm), a ... | 1991 | 1708400 |
| dehydroandrographolide succinic acid monoester as an inhibitor against the human immunodeficiency virus. | dehydroandrographolide succinic acid monoester (dasm) is the dehydroandrographolyl ester of succinic acid; and andrographolide, from which dasm is made, is the major diterpenoid lactone found in the chinese medicinal herb, andrographis paniculata. dasm has been found to be an inhibitor against the human immunodeficiency virus (hiv) in vitro. it was nontoxic to the h9 cell at the concentrations of 50-200 (average, 108) micrograms/ml and was inhibitory to the hiv-1 (iiib) at the minimal concentrat ... | 1991 | 1708503 |
| interactions between interferon and the human immunodeficiency virus. | | 1990 | 1708817 |
| bi-rg-587 is active against zidovudine-resistant human immunodeficiency virus type 1 and synergistic with zidovudine. | a series of dipyridodiazepinones have been shown to be potent inhibitors of human immunodeficiency virus type 1 (hiv-1) reverse transcriptase. the lead compound, bi-rg-587, had a 50% inhibitory concentration of 84 nm against hiv-1 reverse transcriptase activity. this compound reduced plaque formation of hiv-1 in hela cells expressing the cd4 receptor by 50% at 15 nm. bi-rg-587 at comparable concentrations inhibited the production of p24 antigen following the acute infection of cem t-lymphoblasto ... | 1991 | 1708976 |
| anti-human immunodeficiency virus synergism by zidovudine (3'-azidothymidine) and didanosine (dideoxyinosine) contrasts with their additive inhibition of normal human marrow progenitor cells. | the anti-human immunodeficiency virus (hiv) activity and hemopoietic toxicity of zidovudine (azt) and didanosine (dideoxyinosine;ddi), alone and in combination, were assessed in a variety of cell types. azt was more potent than ddi as an inhibitor of hiv in vitro. synergistic inhibition of hiv by the combination of these agents was observed in mt4 cells, peripheral blood lymphocytes, and macrophages. toxicity assessment in vitro by using progenitor (erythroid and granulocyte-macrophage) colony-f ... | 1991 | 1708977 |
| expression of active human immunodeficiency virus type 1 protease by noninfectious chimeric virus particles. | to generate nonpathogenic viral particles which express active human immunodeficiency virus type 1 (hiv-1) protease (pr), plasmids containing sequences from the genomes of hiv-1 and moloney murine leukemia virus (m-mulv) were constructed. either the pr coding region alone; the gag, pr, and reverse transcriptase protein-coding regions; or the complete gag and pol protein-coding regions from hiv-1 were substituted for the corresponding regions of a full-length m-mulv clone to yield the chimeric pl ... | 1991 | 1709693 |
| selective antiviral activity of synthetic soluble l-tyrosine and l-dopa melanins against human immunodeficiency virus in vitro. | melanins are pigments found in hair, skin, irides of the eye, and brain. their functions in mammals include protection from exposure to sunlight, camouflage from predators, sexual recognition within species, and possible electron transfer reactants. most natural melanins exist in an insoluble form, which is one reason there is little information on the biological properties of soluble melanins. here, synthetic soluble melanins were obtained by chemical oxidation of l-tyrosine or spontaneous oxid ... | 1991 | 1709802 |
| immune response to a major epitope of p24 during infection with human immunodeficiency virus type 1 and implications for diagnosis and prognosis. | a sequential inhibition enzyme-linked immunoassay (sieia) using a peroxidase-conjugated monoclonal antibody reacting to the sequence aaewdrvhp of p24hiv-1 (amino acids 209 to 217 of p55) was developed in order to detect and determine the titer of antibody to this epitope in various populations of human immunodeficiency virus type 1 (hiv-1)-positive patients. there was a good correlation between sieia and a commercially available competition assay that uses recombinant p24 protein and polyclonal ... | 1991 | 1709947 |
| in vitro efficacy of anti-hiv immunotoxins targeted by various antibodies to the envelope protein. | six different anti-hiv envelope antibodies and one irrelevant control antibody were coupled to ricin a chain and tested for their efficacy in inhibiting hiv tissue culture infections. the anti-hiv antibodies consisted of five monoclonals, three of murine and two of human origin, and one polyclonal preparation prepared by affinity purifying pooled serum antibodies from hiv-infected humans on rgp160. the binding specificity of the antibodies was defined by elisa by using recombinant envelope prote ... | 1991 | 1710247 |
| an igg human monoclonal antibody that reacts with hiv-1/gp120, inhibits virus binding to cells, and neutralizes infection. | a human mab (hmab) termed f105 was obtained by fusion of antibody-producing ebv-transformed cells with the hmma2.11tg/o cell line. f105 is an igg1 kappa antibody that binds to the surfaces of cells infected with all hiv-1 strains tested: mn, rf, iiib, and sf2, but not uninfected cells. the hmab immunoprecipitates gp120 from all four strains. f105 does not react with denatured gp120 on western blots, but does react with viral lysates and purified gp120 dotted onto nitrocellulose filter paper unde ... | 1991 | 1710248 |
| identification of a major human immunodeficiency virus-1 reverse transcriptase epitope recognized by mouse cd4+ t lymphocytes. | delineation of major t helper cell recognition sites of human immunodeficiency virus (hiv-1) proteins represents one important step in the design of an efficient acquired immune deficiency syndrome (aids) vaccine. towards this end, we have explored the immunogenicity of hiv-1bru proteins in the mouse model. preliminary experiments revealed that inbred mice primed with whole inactivated hiv-1 developed strong cd4+ t cell proliferative responses to a variety of recombinant viral proteins including ... | 1991 | 1710563 |
| characterization of human antibody-binding sites on the external envelope of human immunodeficiency virus type 2. | antibody-reactive peptide scanning (pepscan) using overlapping nonapeptides and human sera as probes allows the identification of amino acids contributing significantly to antigen-antibody interaction. five-hundred and two overlapping nonapeptides derived from the human immunodeficiency virus type 2 strain rod (hiv-2rod) external envelope glycoprotein gp125 were synthesized to serve as probes for reactivity with eight sera of hiv-2-infected individuals. fifteen antibody-binding regions were iden ... | 1991 | 1710645 |
| hepatitis c virus antibodies among different groups at risk and patients with suspected non-a, non-b hepatitis. | 4000 sera were tested for antibodies against hepatitis c virus (hcv) by means of an elisa using the c100-3 antigen. 38.9% of patients with non-a, non-b hepatitis following blood transfusion (n = 108) had hcv antibodies. among patients with chronic liver damage of unknown origin (n = 316) 30.4% were anti-hcv positive, and in 2,506 patients with transitional or chronic elevation of transaminases 14.8% showed hcv antibodies. haemophiliacs (n = 26) with 65.4% anti-hcv positives and drug addicts (n = ... | 1991 | 1711018 |
| cd4+ lipid bilayers. a model for human immunodeficiency virus type 1 coat protein binding. | gp120, the coat glycoprotein of the human immunodeficiency virus type 1 (hiv1) binds to a molecule on the surface of a class of t-lymphocytes, cd4, which is also the receptor for major histocompatibility complex class ii (mhcii). to study the events that follow the interaction of gp120 with cd4, we have incorporated cd4 into lipid bilayers and recorded the electrical changes which occur after the addition of gp120. interaction of gp120 to cd4-containing bilayers induces multistate ion-permeable ... | 1991 | 1711033 |
| highly potent and selective inhibition of human immunodeficiency virus type 1 by a novel series of 6-substituted acyclouridine derivatives. | in the search for novel derivatives of 1-[2-(hydroxyethoxy)methyl]-6-(phenylthio)thymine (hept), we have found that several 5-ethyl-6-(3,5-dimethylphenylthio)uracil and 5-ethyl-6-(3,5-dimethylbenzyl)uracil analogues are exquisitely potent and selective inhibitors of human immunodeficiency virus type 1 (hiv-1) replication in a variety of cell culture systems. of this series, 5-ethyl-1-ethoxymethyl-6-(3,5-dimethylbenzyl)uracil (e-ebu-dm) emerged as the most active congener. its 50% inhibitory conc ... | 1991 | 1711148 |
| 9-[(2rs)-3-fluoro-2-phosphonylmethoxypropyl] derivatives of purines: a class of highly selective antiretroviral agents in vitro and in vivo. | a new class of compounds, 9-[(2rs)-3-fluoro-2-phosphonylmethoxypropyl] [(rs)-fpmp] derivatives of purines, is described that has selective activity against a broad spectrum of retroviruses [including human immunodeficiency virus type 1 (hiv-1) and type 2 (hiv-2)] but not other rna or dna viruses. this activity spectrum is completely different from that of the parental compounds, 9-[(2s)-3-hydroxy-2-phosphonylmethoxypropyl] [(s)-hpmp] derivatives of purines, which are active against a broad range ... | 1991 | 1711214 |
| the p15 carboxyl-terminal proteolysis product of the human immunodeficiency virus type 1 reverse transcriptase p66 has dna polymerase activity. | the reverse transcriptase of human immunodeficiency virus type 1 is a heterodimeric protein consisting of two polypeptides with masses of 66 and 51 kda and has, as a second enzymatic activity, rnase h activity. the 66-kda polypeptide can be cleaved by the virus-encoded protease to yield polypeptides of 51 and 15 kda. the latter has been characterized as possessing rnase h activity [hansen, j., schultze, t., mellert, w. & moelling, k. (1988) embo j. 7, 239-243]. we have purified simultaneously th ... | 1991 | 1711222 |
| effect of the calcium channel blocker verapamil on human immunodeficiency virus type 1 replication in lymphoid cells. | cell signaling events are known to affect human immunodeficiency virus type 1 (hiv-1) replication. treatment of lymphoid cem cells with the calcium channel blocker verapamil (25-75 microm) enhanced hiv-1 expression in acute, whole virus infection experiments, despite lowering intracellular calcium levels, ablating the acute rise in intracellular calcium normally seen with infection, and lengthening the doubling time of cell replication. verapamil had no effect on cell surface cd4 expression. tra ... | 1991 | 1711554 |
| comparison of linear antigenic sites in the envelope proteins of human immunodeficiency virus (hiv) type 2 and type 1. | the occurrence of dominant linear antigenic sites in the envelope glycoproteins of human immunodeficiency virus type 2 (hiv-2) was evaluated. twenty-five peptides representing different regions of hiv-2, strain sbl-6669, were synthesized. for comparison the corresponding peptides of hiv-1, strain bru, were also prepared. the peptides were tested in enzyme-linked immunosorbent assay (elisa) with human sera from individuals with proven hiv-1 or hiv-2 infection and simian sera from animals infected ... | 1991 | 1712215 |
| monoclonal antibodies define linear and conformational epitopes of hiv-1 pol gene products. | purified recombinant reverse transcriptase (rt) from human immunodeficiency virus type 1 (hiv-1) was used to raise 21 monoclonal antibodies with anti-rt specificities. the antibodies were characterized using western blotting against native virus and recognized either the p66 or p66, p51 components of rt. further immunoblotting using either cyanogen bromide fragmented rt or truncated mutants of rt along with cross-competition studies enabled the location of various immunogenic regions of rt to be ... | 1991 | 1712217 |
| competition elisa using a human monoclonal antibody for detection of antibodies against human immunodeficiency virus type 1. | a novel competition elisa for detection of antibodies against hiv-1 was developed. the assay is based on competition at the single epitope level and utilises a human monoclonal antibody and an e. coli-produced fragment of the transmembrane glycoprotein gp41. the sensitivity of the assay was 100% in tests on 247 serum samples obtained from 219 individuals previously shown to be hiv-1 antibody positive by both conventional indirect elisa and the immunoblotting test. the patients represented variou ... | 1991 | 1712361 |
| novel non-nucleoside inhibitors of hiv-1 reverse transcriptase. 1. tricyclic pyridobenzo- and dipyridodiazepinones. | novel pyrido[2,3-b][1,4]benzodiazepinones (i), pyrido[2,3-b][1,5]benzodiazepinones (ii), and dipyrido[3,2-b:2',3'-e][1,4]diazepinones (iii) were found to inhibit human immunodeficiency virus type 1 (hiv-1) reverse transcriptase in vitro at concentrations as low as 35 nm. in all three series, small substituents (e.g., methyl, ethyl, acetyl) are preferred at the lactam nitrogen, whereas slightly larger alkyl moieties (e.g., ethyl, cyclopropyl) are favored at the other (n-11) diazepinone nitrogen. ... | 1991 | 1712395 |
| characterization of murine monoclonal antibodies directed against the core proteins of human immunodeficiency virus types 1 and 2. | monoclonal antibodies (mabs) raised against the core proteins of human immunodeficiency virus type 1 (hiv-1; laboratory strain htlv-iiib) and hiv-2 (strain rod) were investigated in a variety of tests, e.g., enzyme-linked immunosorbent assay (elisa), immunostaining of western immunoblots, immunofluorescence, immunoprecipitation, and alkaline phosphatase anti-alkaline phosphatase assay. the mabs were grouped according to their cross-reactions. seven hiv-1-specific mabs reacted exclusively with hi ... | 1991 | 1712863 |
| passive immunization to prevent mother-infant transmission of human immunodeficiency virus: current issues and future directions. | a definitive conclusion regarding the potential for the presence of neutralizing antibody to epitopes of the v3 loop to attenuate or prevent vertical transmission of hiv infection cannot be made based on the results of these four studies. however, the studies provide an intriguing suggestion that it may be possible to identify an epitope or array of epitopes from the v3 loop of judiciously selected hiv isolates that could induce protective immunity against hiv. future collaborative studies are n ... | 1991 | 1712936 |
| human immunodeficiency virus reverse transcriptase ribonuclease h: specificity of trna(lys3)-primer excision. | two model substrates were prepared to examine the mechanism of trna-primer excision catalyzed by reverse transcriptase associated ribonuclease h (rt-rnase h). the first model substrate contained sequences from the hiv genome and was designed to be structurally similar to the dna-extended trna created by initiation of minus-strand dna synthesis during retroviral replication. the dna-extended rna was a template and was annealed to a dna oligonucleotide that primed reverse transcription of the rna ... | 1991 | 1713059 |
| human immunodeficiency virus type 1 infection of endothelial cells in vitro. | in order to establish whether endothelial cells are involved in immunodeficiency virus type 1 (hiv-1) infection, we performed a virological study on endothelial cells isolated from human adipose tissue and infected with hiv-1 in vitro. supernatants from cultures showed a reverse transcriptase activity starting one day after hiv inoculation. viral rescue was significantly impaired in cycloheximide treated cells confirming a de novo synthesis of viral products. | 1991 | 1713288 |
| expression of the heterodimeric form of human immunodeficiency virus type 2 reverse transcriptase in escherichia coli and characterization of the enzyme. | a system for the expression of recombinant human immunodeficiency virus type 2 (hiv-2) reverse transcriptase (rt) in escherichia coli has been developed, which allows purification of the heterodimeric form of the enzyme as well as the separate purification of the two subunits. it is shown that equilibrium formation between monomeric and homodimeric forms of the recombinant 66- and 51-kda subunits is considerably more rapid than in the case of the corresponding homodimeric forms of hiv-1 rt. in a ... | 1991 | 1713589 |
| a cluster of continuous antigenic structures in the transmembrane protein of hiv-1: individual patterns of reactivity in human sera. | we investigated the antigenicity of a highly conserved region in the transmembrane protein of the human immunodeficiency virus type 1 (hiv-1). in order to identify antigenically important residues, amino-acid sequences of synthetic peptides representing this region were varied systematically: single residues were omitted from the sequence of hiv-env 583-599; threonines were substituted for pairs of residues in hiv-env 581-599; the sequences of heptadeca-peptides were shifted by single residues. ... | 1991 | 1713646 |
| oxathiin carboxanilide, a potent inhibitor of human immunodeficiency virus reproduction. | oxathiin carboxanilide (oc), nsc 615985, a compound originally synthesized as a potential fungicide, was demonstrated to be highly active in preventing human immunodeficiency virus (hiv)-induced cell killing and in inhibiting hiv reproduction. virus-infected cd4+ lymphocytes were completely protected by 0.5 microm oc, whereas no toxicity was observed at concentrations below 50 microm oc. production of infectious virus, viral p24 antigen, and virion reverse transcriptase were reduced by oc at con ... | 1991 | 1713689 |
| the use of hematopoietic growth factors in hiv infection and aids-related malignancies. | human immunodeficiency virus (hiv) infection is associated with multiple defects in immune regulation and hematopoiesis. these defects include decreased proliferation of hematopoietic progenitor cells and increased destruction of mature cells. there are also disturbances of regulatory cytokines. as a result, hematopoietic cytopenias are common and the tolerance of myelosuppressive therapy is poor. one successful approach to the management of these clinical problems is the use of hematopoietic gr ... | 1991 | 1713806 |
| deletions in the trna(lys) primer-binding site of human immunodeficiency virus type 1 identify essential regions for reverse transcription. | the initiation of human immunodeficiency virus type 1 (hiv-1) reverse transcription occurs by the extension of a trna primer bound near the 5' end of the genomic rna at a position termed the primer-binding site (pbs). the pbs is an 18-nucleotide region of the hiv-1 genome complementary to cellular trna(lys). to further investigate the sequence requirements for the pbs in reverse transcription, deletions in the pbs were created and subcloned into a plasmid containing the infectious hiv-1 proviral ... | 1991 | 1714513 |
| characterization of monoclonal antibodies against the human immunodeficiency virus matrix protein, p17gag: identification of epitopes exposed at the surfaces of infected cells. | eight monoclonal antibodies reactive with the matrix protein of human immunodeficiency virus type 1 (hiv-1), p17gag, were isolated from rats which had been immunized with solubilized hiv-1 lysate. the epitope specificities of these antibodies were determined with a series of synthetic peptides representing overlapping regions of p17. six of the antibodies were mapped to three distinct regions of p17, while two antibodies (g11g1 and g11h3) reacted only with intact recombinant p17, suggesting that ... | 1991 | 1714518 |
| several cd4 domains can play a role in human immunodeficiency virus infection in cells. | the human immunodefiency virus (hiv) uses the human cd4 glycoprotein as a receptor for infection of susceptible cells. cells expressing a series of mutated forms of the cd4 gene have shown a variability in their ability to support replication of three hiv type 1 (hiv-1) and three hiv-2 strains. moreover, when different stages of virus production were examined by a variety of assays, a consistent delay was observed in all cell lines containing cd4 mutants compared with those with intact full-leng ... | 1991 | 1714523 |
| localization of immunogenic domains in the human immunodeficiency virus type 2 envelope. | highly immunogenic domains have not yet been defined in the extracellular protein of the human immunodefiency virus type 2 (hiv-2) envelope. in this study, six contiguous segments covering the entire hiv-2st envelope were amplified and cloned into a bacterial expression vector to localize the relative immunogenic reactivity of different regions of the molecule by western blot (immunoblot) analysis. our results demonstrate that the extracellular protein of the hiv-2 envelope contains highly immun ... | 1991 | 1714524 |
| the vpx gene of simian immunodeficiency virus facilitates efficient viral replication in fresh lymphocytes and macrophage. | vpx is a unique open reading frame found in simian immunodeficiency virus (siv) and human immunodeficiency virus type 2 (hiv-2) but not in hiv-1. it encodes a 12- to 16-kda virion-associated protein. although vpx is dispensable for viral replication in several established human lymphocyte cell lines, there is no consensus regarding whether this gene is required for efficient viral replication in freshly isolated lymphocytes. we report here that the vpx mutant of sivmac exhibits different degrees ... | 1991 | 1714525 |
| hp 0.35, a cephalosporin degradation product is a specific inhibitor of lentiviral rnases h. | penicillins, cephalosporins and other betalactam antibiotics are widely used antibacterial drugs. recently it was found that some of them also have effects on proliferating eukaryotic cells (neftel, k.a. and hübscher, u. (1987) antimicrob. agents chemother. 31, 1657-1661), and one such effect was shown to be the inhibition of dna polymerase alpha (huynh do,u., neftel, k.a., spadari, s. and hübscher, u. (1987) nucl. acids res. 15, 10495-10506). the data suggested that degradation products of beta ... | 1991 | 1714562 |
| human immunodeficiency virus type 2 vpx protein augments viral infectivity. | the genomes of hiv and siv are complex and contain several accessory genes which modulate viral replication and pathogenicity. one of these genes, vpx, is unique to the hiv-2/siv group of viruses and encodes a virion-associated protein of unknown function. to examine the function of vpx, we constructed a vpx-deficient hiv-2 proviral clone and characterized its in vitro biological properties. following transfection into immortalized t-cell lines, vpx-mutant hiv-2 was fully replication competent a ... | 1991 | 1714662 |
| prevalence of hepatitis c virus antibodies among patients infected with human immunodeficiency virus. | a study was undertaken to determine the prevalence and risk factors for serological evidence of hepatitis c virus (hcv) infection in patients infected with the human immunodeficiency virus (hiv). tests for anti-hcv antibody were carried out by enzyme-linked immunoassay (eia) on 101 hiv-infected patients from two university-based outpatient clinics. anti-hcv antibody reactive samples were tested by using a recombinant immunoblot assay (riba) for hcv antibodies. fourteen of 101 (13.9%) hiv-infecte ... | 1991 | 1715384 |
| characterization of monoclonal antibodies identifying type and strain-specific epitopes of human immunodeficiency virus type 1. | several hybridoma cell lines were raised against the highly cytopathic zaïrian isolate of human immunodeficiency virus (hiv), hiv1-ndk. the specificity of the secreted monoclonal antibodies (mab) was demonstrated by immunoblotting, radioimmunoprecipitation and immunofluorescence. two hybridoma cell lines secreted mab reacting with independent epitopes of the ndk p17 capsid protein and its precursors. one, rl16.24.5, is specific for the ndk isolate whereas the other, rl16.45.1, along with anti-p2 ... | 1991 | 1715507 |
| compatibility of rev gene activity in the four groups of primate lentiviruses. | the compatibility of rev genes derived from various primate immunodeficiency viruses of all distinct subgroups identified was assessed in three experimental systems: complementation experiments between proviral rev and gag mutants, evaluation of the ability of the rev gene products to activate proviral reporters, and examination of the capacity of various viruses to augment marker gene expression in the infected reporter cell lines. in all systems, human immunodeficiency virus type 1 (hiv-1) rev ... | 1991 | 1716025 |
| preliminary studies of photoinactivation of human immunodeficiency virus in blood. | the transmission of human immunodeficiency virus (hiv) by blood or blood components is a major concern in blood banking. a photodynamic flow cell system was designed to inactivate cell-free hiv mixed with blood from a healthy donor. blood containing 4 x 10(3) infectious units of hiv was treated with 10 and 20 micrograms per ml of commercially available dihematoporphyrin ether (dhe) per ml. aliquots of this mixture were then held in the dark or irradiated in a flow cell illuminated at a light ene ... | 1991 | 1716385 |
| electrochemiluminescence detection for development of immunoassays and dna probe assays for clinical diagnostics. | electrochemiluminescence (ecl) has been developed as a highly sensitive process in which reactive species are generated from stable precursors (i.e., the ecl-active label) at the surface of an electrode. this new technology has many distinct advantages over other detection systems: no radioisotopes are used; detection limits for label are extremely low (200 fmol/l); the dynamic range for label quantification extends over six orders of magnitude; the labels are extremely stable compared with thos ... | 1991 | 1716534 |
| [the activation of the transposition cycle ty element by the reverse transcriptase of the human immunodeficiency virus in saccharomyces cerevisiae yeasts]. | | 1991 | 1716549 |
| role of conserved gp41 cysteine residues in the processing of human immunodeficiency virus envelope precursor and viral infectivity. | all animal retroviruses whose nucleotide sequences have been determined contain two or three closely spaced cysteine residues in the extracellular domain of the env-encoded transmembrane protein. using human immunodeficiency virus type 1 gp41 as a working model, the functional significance of these highly conserved cysteines was investigated. we report here that substituting the two conserved cysteine residues in this domain of gp41 with glycine residues resulted in the loss of viral infectivity ... | 1991 | 1717722 |
| nonnucleoside reverse transcriptase inhibitors that potently and specifically block human immunodeficiency virus type 1 replication. | certain bis(heteroaryl)piperazines (bhaps) are potent inhibitors of the human immunodeficiency virus type 1 (hiv-1) reverse transcriptase (rt) at concentrations lower by 2-4 orders of magnitude than that which inhibits normal cellular dna polymerase activity. combination of a bhap with nucleoside analog hiv-1 rt inhibitors suggested that together these compounds inhibited rt synergistically. in three human lymphocytic cell systems using several laboratory and clinical hiv-1 isolates, the bhaps b ... | 1991 | 1717988 |
| human immunodeficiency virus can infect the apical and basolateral surfaces of human colonic epithelial cells. | the gastrointestinal tract is considered to be a major route of infection for the human immunodeficiency virus (hiv). to understand the interaction of hiv with epithelial cells of the intestinal mucosa, we have studied the infection of a human colon cancer cell clone ht-29-d4. the enterocyte-like differentiation of this clone can be modulated in vitro according to the concentration of glucose. we show that: (i) undifferentiated ht-29-d4 cells can be infected by hiv types 1 and 2 (hiv-1 and hiv-2 ... | 1991 | 1718004 |
| effect of evans blue and trypan blue on syncytia formation and infectivity of human immunodeficiency virus type i and type ii in vitro. | polyanionic compounds were used to inhibit infectivity of human immunodeficiency virus in vitro. suramin, evans blue, and trypan blue were shown to inhibit syncytia formation normally observed when hiv-1-infected cells are cocultured with cd4+ cells. the inhibition was more pronounced with evans blue than with any of the other polyanions studied. the inhibitory effect was significantly weaker in hiv-2 systems. however, the reverse transcriptase activities of both types of viruses were inhibited ... | 1991 | 1718343 |
| brefeldin a inhibits the processing and secretion of envelope glycoproteins of human immunodeficiency virus type 1. | the processing and secretion of the envelope glycoproteins of human immunodeficiency virus type 1 (hiv-1) were studied in chronically infected t cells and in primary macrophages treated with an antiviral antibiotic brefeldin a (bfa). bfa blocks the egress of proteins from the endoplasmic reticulum and has a profound effect on the structure of cis/medial golgi. in molt-3 cells infected with the iiib strain of hiv-1 (molt-3/iiib), bfa inhibited the intracellular processing of gp160. the secretion ... | 1991 | 1718346 |
| broadly neutralizing antibodies targeted to mucin-type carbohydrate epitopes of human immunodeficiency virus. | the cancer-related mucin-type carbohydrate neoantigen tn was found on gp160 and gp120 of human immunodeficiency virus (hiv). immunoglobulin g (igg) and igm monoclonal antibodies (mabs) against tn neutralized infection with cell-free virus and blocked fusion between hiv-infected and uninfected cells. this inhibition was found in infection of both lymphocytic cells and monocytoid cells. viruses tested included six hiv-1 and five hiv-2 isolates propagated in different cells, as well as infectious p ... | 1991 | 1719230 |
| chimeric human immunodeficiency virus type 1/type 2 reverse transcriptases display reversed sensitivity to nonnucleoside analog inhibitors. | human immunodeficiency virus type 1 (hiv-1) reverse transcriptase (rt), an important therapeutic target in the treatment of aids, is effectively inhibited by a class of nonnucleoside analog compounds that includes nevirapine (bi-rg-587) and tetrahydroimidazo[4,5,1-jk]-[1,4]benzodiazepin-2(1h)-one and -thione. we show that both tyrosine residues at positions 181 and 188 flanking the putative catalytic site of hiv-1 rt are required for sensitivity of the enzyme to these compounds. hiv-2 rt, which ... | 1991 | 1719542 |
| detection of mutations associated with zidovudine resistance in human immunodeficiency virus by use of the polymerase chain reaction. | a sensitive and specific polymerase chain reaction (pcr)-based assay was developed for four mutations in the reverse transcriptase gene of human immunodeficiency virus type 1 that have been associated with zidovudine resistance. these mutations were correlated in 366 specimens with zidovudine chemotherapy and resistance. mutations at these four codons were detected only after zidovudine therapy. the usual sequence of appearance of mutations was codons 215, 70, 67, and 219, although individual va ... | 1991 | 1720152 |