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PubMed1992

A comparison of regulatory features in primate lentiviruses.

Historically, research into the regulation of gene expression in primate lentiviruses has focused on human immunodeficiency virus type 1 (HIV-1), the primary cause of acquired immunodeficiency syndrome (AIDS) in humans. The increasing emergence of HIV-2 as a human pathogen, and the importance of the various simian immunodeficiency viruses (SIV) as models for the treatment and prevention of HIV-1-induced disease, suggest that an understanding of gene regulation in these related viruses will become increasingly important. Here, the present state of knowledge in this latter field is reviewed. In general, while the data support the hypothesis that viral gene expression is regulated by very similar mechanisms in all primate lentiviruses, it also is clear that differences in detail do exist. These differences may influence the pathogenic potential of the different strains of primate lentiviruses and must be considered in evaluating SIV as an appropriate in vivo model for HIV-1.

Amino Acid Sequence↗
PubMed1992

Epitopes of human immunodeficiency virus regulatory proteins tat, nef, and rev are expressed in normal human tissue.

The expression of regulatory proteins tat, rev, and nef of human immunodeficiency virus type-1 (HIV-1) and tat of HIV-2 was studied in frozen sections of lymph nodes from HIV-1-infected individuals, and various tissues from uninfected persons. In HIV-1-positive lymph nodes, monoclonal antibodies to HIV-1-tat stained solitary cells in the germinal centers and interfollicular zones, and vascular endothelium. Staining by an anti-nef monoclonal antibody was restricted to follicular dendritic cells, whereas anti-rev antibody bound to fibriohistiocytes and high endothelial venules. The antibodies used labeled several cell types in tissues from uninfected individuals. Anti-HIV-1-tat antibodies labeled blood vessels and Hassall's corpuscles in skin and thymus; goblet cells in intestinal tissue and trachea; neural cells in brain and spinal cord; and zymogen-producing cells in pancreas. Anti-rev antibody stained high endothelial venules, Hassall's corpuscles and histiocytes. One anti-nef antibody solely stained follicular dendritic cells in spleen, tonsil, lymph node and Peyer's patches, whereas two other anti-nef antibodies bound to astrocytes, solitary cells in the interfollicular zones of lymph nodes, and skin cells. The current results hamper the immunohistochemical study for pathogenetic and diagnostic use of HIV regulatory protein expression in infected tissue specimens or cells.

Antibodies, Monoclonal↗
PubMed1992

Replication and apical budding of HIV-1 in mucous-secreting colonic epithelial cells.

The human colonic adenocarcinoma cell line HT29 can be infected with various isolates of human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2). In some cases, the virus was able to perform its complete cycle of replication as demonstrated by the persistent production of mature viral particles in the cell-free culture supernatant. We have cultured HT29 cells chronically infected with the replicative strain HIV1-NDK in a chemically defined serum-free medium. Under these conditions, the cells were able to maintain a high level of viral replication, as demonstrated by reverse transcriptase activities and in situ hybridization studies. By indirect immunofluorescence labeling and electron microscopy, we observed that serum starvation was associated with the differentiation of HIV-1-infected HT29 cells into mucous-secreting cells resembling epithelial goblet cells of the colonic mucosa. These mucous-secreting cells, which accounted for 50% of the overall population, produced mature particles of HIV through their apical membrane in the vicinity of mucous granules. These data suggest that HIV-infected goblet cells in the colonic mucosa may produce the virus in the colorectal lumen; this could explain the route of transmission of HIV in the case of anal intercourse.

Adenocarcinoma↗
PubMed1992

[Study of antigenic structure of HIV-1 protein p24 using monoclonal antibodies].

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.

Acquired Immunodeficiency Syndrome↗
PubMed1992

[Hepatitis C virus antibodies in patients and the normal population].

With regard to the controversial issue of a reduction of transfusion-associated infections by non-remunerated donations, epidemiological data on the prevalence of HIV-1, HIV-2 and hepatitis C virus (HCV) are of particular interest in our country. We investigated four sample categories: (1) healthy employees and workers from Hamburg; (2) hemodialysis patients; (3) hemato-oncological patients, and (4) blood donors, and tried to differentiate between the three disputed vectors of community-acquired (sexually or pregnancy-transmitted), nosocomial and transfusion/transplantation-associated HCV infections. We conclude from our results that--prior to the implementation of blood screening--our carefully selected 'paid blood donors' conferred no higher HCV risks than the general (working) population (0.66 vs. 0.82% HCV antibody prevalence). Besides transfusions/transplantations, significant nosocomial risks apparently exist in hemodialysis units (21.0 vs. 9.5% HCV seroprevalence in polytransfused patients). Preventive measures, e.g. separate dialysis machines for HCV-positive patients, seem to be advisable.

Blood Transfusion↗
PubMed1992

Performance assessment of neonatal dried blood spot testing for HIV antibody.

A study was undertaken to assess the performance of laboratories participating in the UK unlinked anonymised neonatal screening programme for the detection of HIV antibody. A coded panel of 100 contrived dried blood spots prepared form well characterised anti-HIV-1 and anti-HIV-2 positive sera and an anti-HIV negative serum was distributed to eight testing centres. Fifty-one out of 52 anti-HIV-1 positive samples were identified by all eight laboratories: five laboratories identified all 52 specimens. Only one laboratory detected all four anti-HIV-2 positive spots. None of the laboratories reported a seronegative spot as reactive. The sensitivity of anonymised neonatal anti-HIV-1 screening was deemed satisfactory in all participating laboratories but the margin of sensitivity was insufficient to allow pooling of dried blood spot eluates before testing. Technical modifications would be necessary to increase sensitivity for anti-HIV-2 were HIV-2 infection to be reported more frequently in the UK. Performance assessment of the screening programme should be repeated at regular intervals.

AIDS Serodiagnosis↗
PubMedDate not supplied

Salivary and urinary diagnosis of human immunodeficiency viruses 1 and 2 infection in Côte d'Ivoire, using two assays.

This investigation, done at the Institut Pasteur de Cote d'Ivoire 'blind' of the previous serological findings, suggests that GACELISA, a commercial immunoglobulin G capture enzyme immunoassay for anti-human immunodeficiency virus antibody, can be successfully applied to unprocessed saliva and urine specimens. Its accuracy may be as high as that of conventional enzyme assays on serum tested under similar conditions. However, the role of GACPAT, a similar assay, as a cheap alternative screening test for urine remains in doubt unless its non-specificity can be controlled.

HIV Antibodies↗
PubMed1992

A non-radioisotopic reverse transcriptase assay using biotin-11-deoxyuridinetriphosphate on primer-immobilized microtiter plates.

We developed a non-radioisotopic (non-RI) reverse transcriptase assay (RTA). The reverse transcriptase (RT) incorporates biotin-11-deoxyuridine-triphosphate (bio-dUTP) using a poly(rA) template hybridized with oligo(dT) primer that is immobilized on the surface of a 96-well microtiter plate. This assay is thus semi-automated by adapting it to an ELISA testing format. The incorporation of bio-dUTP was enhanced by adding cold dTTP to the reaction mixture, optimally in a molar ratio 4:1 (dTTP:bio-dUTP). This non-RI RTA is more sensitive than the conventional RI assay for the detection of purified Rous-associated virus 2 (RAV-2) and of human immunodeficiency virus type 1 (HIV-1) lysate. Because of its simple procedure, higher sensitivity and non-use of RI materials, the assay can be utilized not only for virological studies but also for routine safety screening of biological products for retroviral contamination.

Avian Leukosis Virus↗
PubMed1992

A new method for measuring reverse transcriptase activity by ELISA.

A new and sensitive assay of reverse transcriptase (RT) activity of retroviruses measures the incorporation of digoxigenin-labelled dUTP in newly synthesized DNA instead of radioactively labelled (3H- or 32P-)dTTP. To avoid difficulties associated with separation of non-incorporated nucleotides from the newly synthesized DNA, biotin-labelled dUTP is added to the reaction mixture in very low concentrations. After reverse transcription, the newly synthesized, doubly labelled DNA is immobilized on streptavidin-coated ELISA wells and evaluated photometrically by binding of peroxidase-conjugated anti-digoxigenin-antibodies (sheep) and subsequent colour development with 2,2'-azino-di[3-ethylbenzthiazolin-sulfonate(6)] (ABTSR) as substrate. For better standardization, it is suggested that RT activity is given in units (one unit of RT is the amount of enzyme incorporating one nanomole of labelled dNTP in 10 min at 37 degrees C into an acid precipitable DNA) rather than in cpm (counts per minute). The method is specific and easy to perform.

Avian Myeloblastosis Virus↗
PubMed1992

HIV-1 ancestry primordial expansions of RRE and RRE related sequences.

The human T-lymphotropic retroviruses HTLV-I and HIV-1/-2 share a complementary patchwork homology in which the RRE regions of HIV-1 and -2 cover 78.1% of a 169 nucleotide (nt) region (PX1,2) positioned precisely between open reading frames PX I and PX II of ATLV (HTLV-I). The sequence character of the PX1,2 region is shown to be influenced by a primordial expansion, CTC2T, originating several hundred nucleotides upstream. A second primordial expansion, AGCU(U/C), is identified and shown to represent 52.1% of the HIV-1 RRE region. It is argued that prior to the present AIDS pandemic the efficiency of the rev receptor was enhanced by an ancestral recombination event.

Base Sequence↗
PubMed1992

(+-)-carbocyclic 5'-nor-2'-deoxyguanosine and related purine derivatives: synthesis and antiviral properties.

Beginning with 3-cyclopenten-1-ylamine hydrochloride, the 5'-nor derivatives of carbocyclic 2'-deoxyguanosine (2), 2'-deoxyadenosine (3), and 2,6-diaminopurine 2'-deoxyribofuranoside (4) have been prepared. These compounds were evaluated for antiviral potential versus herpes simplex virus, varicella-zoster virus, cytomegalovirus, vaccinia virus, vesicular stomatitis virus, and human immunodeficiency virus and found to lack activity. Also, compounds 2-4 were virtually nontoxic toward the host (human diploid fibroblast ESM and HEL) cells. These biological properties may be due to the inability of 2-4 to be phosphorylated to the requisite nucleotide level that is likely to be necessary for biological activity by correlation to carbocyclic 2'-deoxyguanosine (1), which possesses significant antiviral properties as a result of conversion to its 5'-triphosphate derivative.

2-Aminopurine↗
PubMed1992

Selective inhibition of human immunodeficiency viruses by racemates and enantiomers of cis-5-fluoro-1-[2-(hydroxymethyl)-1,3-oxathiolan-5-yl]cytosine.

2',3'-Dideoxy-5-fluoro-3'-thiacytidine (FTC) has been shown to be a potent and selective compound against human immunodeficiency virus type 1 in acutely infected primary human lymphocytes. FTC is also active against human immunodeficiency virus type 2, simian immunodeficiency virus, and feline immunodeficiency virus in various cell culture systems, including human monocytes. The antiviral activity can be prevented by 2'-deoxycytidine, but not by other natural nucleosides, suggesting that FTC must be phosphorylated to be active and 2'-deoxycytidine kinase is responsible for the phosphorylation. By using chiral columns or enzymatic techniques, the two enantiomers of FTC were separated. The (-)-beta-enantiomer of FTC was about 20-fold more potent than the (+)-beta-enantiomer against human immunodeficiency virus type 1 in peripheral blood mononuclear cells and was also effective in thymidine kinase-deficient CEM cells. Racemic FTC and its enantiomers were nontoxic to human lymphocytes and other cell lines at concentrations of up to 100 microM. Studies with human bone marrow cells indicated that racemic FTC and its (-)-enantiomer had a median inhibitory concentration of > 30 microM. The (+)-enantiomer was significantly more toxic than the (-)-enantiomer to myeloid progenitor cells. The susceptibilities to FTC of pretherapy isolates in comparison with those of posttherapy 3'-azido-3'-deoxythymidine-resistant viruses in human lymphocytes were not substantially different. Similar results were obtained with well-defined 2',3'-dideoxyinosine- and nevirapine-resistant viruses. (-)-FTC-5'-triphosphate competitively inhibited human immunodeficiency virus type 1 reverse transcriptase, with an inhibition constant of 2.9 microM, when a poly(I)n.oligo(dC)19-24 template primer was used. These results suggest that further development of the (-)-Beta-enantiomer of FTC is warranted as an antiviral agent for infections caused by human immunodeficiency viruses.

Antiviral Agents↗
PubMed1992

Recombinant antigens in viral diagnosis.

DNA fragments coding for a variety of different viral antigens have been cloned and expressed in Escherichia coli. Selected purified recombinant antigens were used for detection of specific antibodies by means of the ELISA technique. This approach has been used for the development of four different ELISAs for the detection of HIV- and EBV-specific antibodies.

Antibodies, Viral↗
PubMed1992

[Follow-up of blood donors with indeterminate reaction to anti-HIV 1/2 EIA or isolated detection of antibodies to HIV-1 core antigens (anti-p24)].

Over a period of 20 months we identified 10 voluntary blood donors with indeterminate reactions in anti-HIV 1/2 EIA tests. Western blot (WB) patterns of 6 of these 10 donors showed isolated core antibodies (anti-p24), in 4 cases WB patterns were negative. After a median follow-up period of 58 weeks (range 12-93) we have not seen a case of typical seroconversion.

AIDS Serodiagnosis↗
PubMed1992

[Analysis of new criteria for increasing the specificity of commercial Western blots].

We examined the frequency of serum cross-reactivity on Western blot for HIV1 and HIV2. 661 patients with tuberculosis in Abidjan, and 4,899 asymptomatic persons for HIV1 and HIV2 infections were tested. All specimens positive on ELISA for HIV1 or HIV2 were further characterized by synthetic peptide based tests. Confirmed positive samples were tested by HIV1 and HIV2 specific Western blot criteres utilisis. Dual serologic reactivity on synthetic peptide tests was significantly more frequent in HIV positive patients with tuberculosis than asymptomatic subjects. Positive HIV1 Western blots were seen in 61%-86% of specimens positive for HIV2 only on synthetic peptide tests. [Cross-reactivity, to HIV2 Western blots by HIV1 positive specimens was significantly more frequent in patients with tuberculosis than in asymptomatic subjects.] Using recently recommended criteria for HIV1 and HIV2 Western blot interpretation (presence of 2 env bands) reduced the overall proportion of HIV1 positive specimens having a positive HIV2 Western blot from 39% to 14% and HIV2 positive specimens having a positive HIV1 Western blot from 31% to 8%.

Acquired Immunodeficiency Syndrome↗