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

The human immunodeficiency virus (HIV) proteins gp120 and gp41 are the principal immune target in HIV infection. One of the most important trends in the study of AIDS is linked to the mapping of sites involving in the binding to the cell receptor CD4 and in the induction of virus-neutralizing antibodies (VNA). Recent studies have revealed that gp120 as the major domain contains inducing type-specific BNA (PND) and a binding region with CD4 (CD4-BR). PND is located in the hypervariable loop of gp120 (residues 301-336 for a BRU strain), and CD4-BR is in the conservation area (residues 410-450). By using the synthetic fragments from these areas (BRU and MN strains) and HIV-infected persons' sera, the authors established that the immune response to PND and CD4-BR is somewhat interrelated: there is a synchronized response of HIV antibodies to peptides from the two regions in ELISA (r = 0.82). For analysis of this phenomenon, experiments with cross-linked immunoreactivity of rabbit antisera to peptides from PND and CD4-BR with homologous and heterologous peptides were performed by applying three control peptides from HIV and hepatitis B virus. It has been found that there is a cross reactivity between rabbit anti-PND (MN, BRU) and anti-CD4-BR abs. Peptide homological analysis revealed common structural elements for PND and CD4-BR despite significant differences in their proposed functions. There is a large amount of positively charged aa within both PND and CD4-BR which may be involved in gp120-CD4 interaction. Acetylation of Lys residues resulted in complete loss of peptide reactivity.
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PMID:[Peptides from the principal neutralizing and CD4-binding domain: similar immunoreactive properties and structure pattern]. 128 21

The transient expression of the HIV-1 gag genes and a HIV-1 ++trans-activator protein (tat)-encoded was made in cultured CV-1 cells. In recombinant plasmids, the gag gene was under the control of HIV-1 ++trans-activator sequence (tar) and the tat gene was under the control of a 7.5-kd vaccinia promoter. Transactivation of gag gene expression, which was stimulated by a tat gene expression product, was observed in the presence of wild vaccinia virus. The transaction was immunologically evaluated from the binding to monoclonal anti-p17 and anti-p24 antibodies. The findings lead to the discussion whether the regulatory proteins of HIV-1 can express in vaccinia virus vectors.
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PMID:[Expression of HIV-1 tat gene under the control of P 7,5 KD vaccinia virus promoter in CV-1 cells]. 128 22

During the experiments 4 murine and 3 rat hybridomas producing monoclonal antibodies (MAb) against the protein p24 of human immunodeficiency virus type 1 (HIV-1) have been obtained. Using the immunoblotting technique, it was established that all the species of MAb reacted with the same viral proteins which are derivatives of gag gene--p24 and p55. The properties of MAb have been studied in competitive binding. Their ability of binding to different fragments of the gag protein produced by the recombinant plasmids in E. coli cells have been investigated in ELISA. The analysis of the findings suggests that the HIV-1 protein p24 contains at least 3 antigenic epitopes. All species of MAb reacted with 3 different HIV-1 strains and 2 HIV-1 isolates, but failed with 2 different HIV-2 strains. The only MAb NS5E4 can be used as an immunosorbent in the antigenic capture reaction.
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PMID:[Study of antigenic structure of HIV-1 protein p24 using monoclonal antibodies]. 128 23

Specific antibodies to persistent viruses (CMV, EBV, HBV) were detected by ELISA in groups of HIV-infected patients and persons showing indefinite results of the immunoblotting test for HIV-1 antigens, on the one hand, and in HIV-seronegative donors and patients with clinical manifestations of viral infection (CMVI) on the other. The findings indicate that the persons with indefinite immunoblotting test results show elevated blood CMV and HBV antigen levels than in the matched group of seronegative donors. This fact suggests that persistent viral infections might involve in the formation of an indefinite pattern when the sera were tested for HIV. The patients whose sera behaved in such a way represent a clinical risk group for HIV infection and call for further follow-up.
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PMID:[Persistent viruses in serological diagnosis of HIV infection]. 128 24

Some sugar modified analogs of 2'-deoxy-E-5-styryluridine triphosphates were synthesized and examined for their inhibitory effects on eukaryotic DNA polymerases and HIV-1 reverse transcriptase. Among these compounds, 3'-azido-2',3'-dideoxy-E-5-styrylUTP (6) and 2',3'-dideoxy-E-5-styrylUTP (7) showed remarkable inhibitory effects on reverse transcriptase. The mode of action and the influence of the substituent at C-5 of 2',3'-dideoxyUTP analogs will be described.
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PMID:Inhibitory effects of 2'-deoxy-5-styryluridine 5'-triphosphate analogs on retroviral reverse transcriptase and eukaryotic DNA polymerases. 128 6

In preparing for testing a pharmaceutical grade preparation of chimeric (mouse/human) antibody CGP 47,439 in HIV-1 infected individuals, it was administered to Macaca fascicularis (cynomolgus) monkeys to study tolerability, immunogenicity and pharmacokinetics. Four groups of monkeys, three males and three females per group, received respectively four infusions of 0, 1.43, 4.3, and 14.3 mg of CGP 47,439/kg body weight at one-week intervals. The chimeric antibody induced no fever, was tolerated well throughout the 50-day observation period, elicited no tissue damage and no anti-antibody response. The pharmacokinetic profile was similar at all dose levels with a mean T1/2 alpha of 14.2 h (range 11.8-19.3 h) and a mean T1/2 beta of 172.6 h (range 137.2-220.5h). Following four successive antibody infusions serum concentrations of CGP 47,439 increased without reaching a steady state, and its measured concentrations were comparable to the simulated values. Collectively the study has provided safety and pharmacokinetic data that would allow human studies with this antibody in AIDS patients.
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PMID:Mouse/human chimeric anti-HIV-1 gp120 antibody to the principal neutralizing determinant: tolerability and pharmacokinetics in cynomolgus monkeys, Macaca fascicularis. 128 53

Previously, we have reported that conjugation of antisense oligonucleotides to poly(L-lysine) (PLL) lowers their inhibitory concentration in several biological models. We have now tested these conjugates for inhibition of human immunodeficiency virus type 1 (HIV-1) replication. PLL-conjugated oligonucleotides complementary to the translation initiation site of Tat protein protect cells from the cytopathic effect of HIV-1 in acute infection assays. The EC50 of conjugates is approximately 0.15 microM, which represents a strong reduction in concentration as compared to nonconjugated oligonucleotides (EC50 = 20 microM). In contrast with most reports in the literature, we have observed sequence specific antiviral effects with PLL conjugates. This was particularly noteworthy in antiviral experiments performed with HIV-1 isolates presenting heterogeneity in the 5' end of the tat mRNA sequence. Two mismatches at the target site were sufficient to reduce very significantly the antiviral activity of the conjugates but did not modify the effect of nonconjugated oligonucleotides. Unlike free oligonucleotides, PLL-conjugated ones do not interfere with virus penetration and/or reverse transcription as demonstrated by polymerase chain reaction (PCR) analysis of viral DNA.
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PMID:Poly(L-lysine)-conjugated oligonucleotides promote sequence-specific inhibition of acute HIV-1 infection. 128 42

The major neutralizing epitope on the external glycoprotein of HIV-1 was studied with an envelope-specific monoclonal antibody and with a human serum positive for antibodies to HIV-1 proteins, both of which were able to neutralize virus infectivity. The monoclonal antibody reacted specifically with gp120 from HIV-1IIIB, and was shown to neutralize infection of CEM cells by cell-free virions, and inhibited the formation of syncytia normally observed when uninfected cells are cocultured with HIV-1-infected cells. Similar neutralization of viral infection and inhibition of syncytia formation was also demonstrated by the HIV-1-antibody-positive human serum. By examining a number of overlapping peptides from a region of HIV-1 gp120 known to contain a neutralizing epitope, this epitope was localized between amino acids 307 and 320 (V3 loop) in the external glycoprotein molecule. The monoclonal antibody did not interfere with the binding of gp120 to CD4, or with the subsequent step of CD4-induced shedding of gp120 from the viral envelope. However, it blocked the proteolytic cleavage of the V3 loop by thrombin, suggesting that the antibody may be inhibiting the interaction of the loop with other membrane-bound proteins.
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PMID:Characterization of a neutralizing monoclonal antibody to the external glycoprotein of HIV-1. 128 59

The authors report on an anti-hepatitis C virus antibody (HCV Ab) prevalence (6.9%) in 622 homo-bisexual males from Northern Italy, voluntarily attending an HIV and STDs screening program in the period 1984-89. The anti-HCV antibody prevalence shows a significant correlation with: i) presence of serological markers for HBV (O.R. = 3.12, 95% C.I. = 1.53-6.52) and HIV (O.R. = 12.09; C.I. = 6.52-22.52) infection; ii) a stable relationship with an anti-HCV antibody positive partner (O.R. = 7.79; 95% C.I. = 2.50-23.90); iii) more than twenty different male partners per year (O.R. = 2.55; 95% C.I. = 1.17-5.66). These data demonstrate the existence of a sexual transmission of HCV among homosexuals. This route might contribute in maintaining endemic levels of HCV infection in the homo-bisexual population and it might represent an important way of spreading the virus in the general population too.
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PMID:Anti-hepatitis C virus antibodies amongst Italian homo-bisexual males. 128 16

Concurrent infection with HIV-1 and Mycobacterium tuberculosis (TB) is increasingly common in East Africa. In HIV-infected individuals, pulmonary TB tends to occur before the onset of opportunistic infections. A common treatment regimen in developing countries is two months of intramuscular streptomycin combined with twelve months of isoniazid and thiacetazone. TB control programs have found this approach to be of acceptable efficacy with a low incidence of adverse reactions. Anecdotal reports of increasing cases of Stevens-Johnson syndrome, however, prompted a two-month prospective search for cases of severe cutaneous hypersensitivity reactions at Muhimbili Medical Center in Dar es Salaam, Tanzania. Five such patients were admitted to an hospital ward over the two-month period, four of whom were HIV-seropositive and all of whom were being treated with isoniazid and thiacetazone. Two were also receiving streptomycin. Four had extensive mucosal involvement of the eyelids, lips, and mouth, consistent with Stevens-Johnson syndrome. The remaining patient had bullous skin lesions, without mucosal involvement, consistent with an exfoliative dermatitis. On admission, medications were discontinued and patients underwent routine management, including the administration of steroids. Four patients were discharged from the hospital 3-7 weeks after admission with improved conditions. One patient died suddenly after five weeks of hospitalization due to unknown causes. These patients give extra support to observations that thiacetazone is associated with the increased incidence of severe cutaneous hypersensitivity syndrome in people infected with HIV-1. Further studies are needed to quantify the excess morbidity and mortality resulting from this treatment regimen.
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PMID:Severe cutaneous hypersensitivity reactions during treatment of tuberculosis in patients with HIV infection in Tanzania. 128 79


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