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

This report compares the immunogenicity of three different preparations of gp120 [the envelope glycoprotein of the human immunodeficiency virus type 1 (HIV-1) virus]: (a) native, fully glycosylated gp120; (b) a nonglycosylated, denatured form of gp120; and (c) a nonglycosylated peptide representing the "immunodominant" third hypervariable region of the gp120 molecule. Results indicate that the native glycosylated form of gp120 induces a maximal anti-HIV response in which a majority of B cells bind to conformation-dependent epitopes but less than one-fifth recognize the V3 loop region.
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PMID:Comparative immunogenicity of gp120-derived proteins and their induction of anti-V3 loop region antibodies. 128 Jun 82

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.
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PMID:Replication and apical budding of HIV-1 in mucous-secreting colonic epithelial cells. 128 Jun 83

Pulmonary immunity has not been studied in children with acquired immunodeficiency syndrome (AIDS) or tuberculosis (TB), even though lungs of both children and adults infected with human immunodeficiency virus (HIV-1) or Mycobacterium tuberculosis are affected frequently and severely. In the present studies, the distributions of T (CD3+, CD4+, CD8+) and B (CD19+) lymphocytes in bronchoalveolar lavage fluid (BALF) and blood of children with AIDS (N = 28) and children with pulmonary TB (N = 18) were determined using direct immunofluorescence (flow microfluorimetry). The distributions of lymphocyte subsets in BALF differed dramatically from those in blood. In pediatric AIDS, reduction of CD4/CD8 ratio was much more pronounced in BALF than in peripheral blood (0.15 +/- 0.04 vs. 0.43 +/- 0.11). This difference was due to selective depletion of BALF CD4+ lymphocytes, rather than to a great influx of CD8+ cells into the lung. In childhood TB, the CD4/CD8 ratio in BALF also was significantly decreased, despite its elevation in blood (1.02 +/- 0.26 vs. 1.96 +/- 0.32). The results show that (1) examination of peripheral blood lymphocytes does not reflect the kind and extent of changes observed in the distribution of pulmonary lymphocyte subsets, and (2) the profound decrease of the CD4/CD8 ratios in BALF of children with AIDS or TB is due to decreased percentages and absolute numbers of BALF CD4+ lymphocytes. The data suggest that analysis of BALF provides a more accurate evaluation of the patient pulmonary immune status than monitoring peripheral blood.
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PMID:Different distributions of lung and blood lymphocyte subsets in pediatric AIDS or tuberculosis. 128 Sep 36

Immunodominant antibody-binding sites were mapped using overlapping synthetic peptides of the structural proteins p17 and p24 of human immunodeficiency virus type 1 (HIV-1). Using sera from HIV-1-infected individuals at a variety of disease states, three major epitopes were identified within p17 and one within p24. Antibodies which recognized these epitopes were present in all risk groups throughout all stages of HIV infection, regardless of the presence of high levels of serum p24 antigen.
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PMID:Immunodominant epitopes of HIV-1 p17 and p24. 128 Sep 55

Three murine monoclonal antibodies (MAbs) F5-2, F5-4, and F5-16 defining three different epitopes on the major core protein p24 of the human immunodeficiency virus type 1 (HIV-1) were epitope mapped using a random fragment expression library representing the p17- and p24-encoding part of the gag open reading frame. F5-2 defined an epitope within amino acids (aa) 14-23 at the N-terminus of p24, and F5-4 defined an epitope within aa 153-174 in the C-terminus of p24. F5-16 did not recognize any of the fusion proteins produced by the expression library indicating that this MAb defines a true conformational epitope on p24. Since the N-terminus of p24 has been reported to be immunosilent in humans, 356 HIV-1 antibody-positive serum samples were tested for reactivity against the region of p24 defined by F5-2. More than one third of the samples recognized this region indicating that it is immunoreactive and, further, the presence of antibodies against this region was associated with a reduced CD4 cell count.
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PMID:Mapping of linear B-cell epitopes on the major core protein p24 of human immunodeficiency virus type 1 (HIV-1). 128 Sep 56

First images on a nanometer scale of reverse transcriptases (RT) of the human immunodeficiency virus (HIV-1) and of the Moloney murine leukemia virus (MuLV) obtained by scanning tunneling microscopy (STM) are reported. The common feature of the observed molecules is a ring-type or horseshoe shape with hole diameters of approximately 30 A. The STM images are compared with high resolution transmission electron microscopy (TEM) and existing structure predictions. The similarities of the structural data obtained by STM and TEM and their agreement with the structure prediction for the RT of HIV-1 shows the principal possibility to image such biomolecules by STM.
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PMID:Direct observation of reverse transcriptases by scanning tunneling microscopy. 128 Sep 57

We have recently demonstrated that human immunodeficiency virus type 1 (HIV-1) recombinant envelope glycoprotein precursor gp160 (rgp160) behaves as a mannosyl/N-acetylglucosaminyl (GlcNAc) binding protein. If such a carbohydrate-binding property were of biological relevance it should be shared by other related primate immunodeficiency viruses such as HIV-2. The present study confirms this hypothesis and extends these findings by showing that HIV-2 recombinant gp140 (rgp140) specifically interacts with three affinity matrices substituted by synthetic or natural carbohydrate structures: D-mannose-divinylsulphone-agarose, para-aminophenyl-beta-D-GlcNAc-agarose and the natural glycoprotein, bovine fetuin, also coupled to agarose. Binding of rpg140 to the matrices was inhibited by alpha-D-Man17-BSA (where BSA is bovine serum albumin), beta-D-GlcNAc47-BSA and fetuin, and by glycopeptides derived from pronase-treated porcine thyroglobulin. Glycopeptides obtained after endoglycosidase H treatment of thyroglobulin had a limited inhibitory effect, whereas beta-D-Gal17-BSA and beta-D-glucan had no effect. These results indicate that, like HIV-1 envelope glycoprotein, HIV-2 rgp140 interacts with high-mannose and with the mannosyl core of complex-type N-linked glycans, as well as with the N-acetylglucosaminyl core of oligosaccharidic structures.
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PMID:Mannosyl/N-acetyl-beta-D-glucosaminyl binding properties of the envelope glycoprotein of human immunodeficiency virus type 2. 128 Oct 21

Zalcitabine is an analogue of the nucleoside deoxycytidine which, when intracellularly converted to an active triphosphate metabolite, inhibits replication of human immunodeficiency virus (HIV). Zalcitabine is thought to act in the early phase of HIV replication by inhibiting reverse transcriptase and terminating the viral DNA chain. In vitro, zalcitabine is one of the more effective nucleoside analogues currently in clinical use for HIV infection, with 0.5 mumol/L concentrations completely inhibiting HIV replication in human T lymphocyte cell lines. In clinical trials, p24 antigen levels decreased and CD4 cell counts increased in patients with acquired immunodeficiency syndrome (AIDS) receiving zalcitabine > or = 0.03 mg/kg/day as monotherapy. Dose-dependent adverse effects that include peripheral neuropathy, stomatitis and rash, restrict long term use at higher dosages, and it is unclear whether zalcitabine monotherapy is as effective as zidovudine in extending survival in HIV-infected patients. Alternating or concomitant therapy with zalcitabine and zidovudine provides effective inhibition of viral replication and disease progression (as measured by improvements in CD4 cell counts) with lower and less toxic dosage regimens. At present, therefore, zalcitabine has a place in AIDS therapy both in combination with zidovudine, and as monotherapy for patients unable to tolerate zidovudine.
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PMID:Zalcitabine. A review of its pharmacology and clinical potential in acquired immunodeficiency syndrome (AIDS). 128 Oct 77

The primary cellular receptor for the human immunodeficiency viruses type 1 (HIV-1) and type 2 (HIV-2) is the CD4 antigen. HIV infection of CD4+ cells is initiated by binding of the virus to the cell surface, via a high affinity interaction between CD4 and the HIV outer envelope glycoprotein, gp120. The development of model systems using soluble recombinant forms of CD4 (sCD4) has allowed kinetic and thermodynamic analyses of CD4 binding to gp120, and study of the post-binding events leading to virus-cell membrane fusion. It has thus been demonstrated that the affinity of sCD4 for gp120 on virions or HIV-infected cells depends on both the primary sequence and the tertiary structure of gp120 in the membrane. With cell-line adapted isolates of HIV-1, sCD4 binding induces conformational changes in gp120, leading to the complete dissociation of gp120 from the transmembrane glycoprotein, gp41, and exposing cryptic epitopes of gp41. Similar observations have been made with cell-anchored CD4; exposure of cryptic gp41 epitopes occurs at the fusion interface between clusters of CD4-expressing and HIV-infected cells. Thus, for HIV-1, CD4 induces exposure of fusogenic components of gp41 which triggers virus-cell membrane coalescence. This is termed receptor-mediated activation of fusion. With primary isolates of HIV-1 and the related lentiviruses, HIV-2 and simian immunodeficiency virus (SIV), the CD4-induced molecular rearrangements in gp120 are more subtle, implying that there is a spectrum of responses to sCD4 binding. The high-affinity binding site on CD4 for gp120 is necessary and probably sufficient for activation of HIV fusion, although other regions of CD4 may indirectly influence viral entry. There are two regions on the envelope glycoproteins which are recognized as playing a role in HIV entry: the N-terminus of gp41 and the gp120 V3 loop. The roles of these domains are discussed.
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PMID:CD4 activation of HIV fusion. 128 Dec 2

We performed a retrospective analysis of longitudinal clinical and immunologic data obtained from 22 children in the early stages of infection with human immunodeficiency virus (HIV) when they developed varicella. We studied the course of HIV infection to determine whether clinical deterioration occurred after chickenpox. We examined the following indices: growth and development; neurologic status; helper T lymphocyte counts; blood values of core (p24) antigen of HIV; changes in the stage of HIV infection; and need for administration of zidovudine. We studied children for a mean of 2.8 years and for as long as 9.8 years after onset of varicella. There was little evidence that chickenpox affected HIV infection. Three (14%) children developed clinical zoster, 2 of whom (9%) had evidence of chronic infection with varicella-zoster virus. One additional child (5%) had 2 episodes of chickenpox. These observations suggest that children with early HIV infection could be considered for immunization with live attenuated varicella vaccine, which would be predicted to decrease their morbidity from varicella-zoster virus.
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PMID:Varicella does not appear to be a cofactor for human immunodeficiency virus infection in children. 128 8


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