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

The effect of increasing concentrations (from 0.01 to 10 micrograms/ml) of HIV-1 envelope glycoproteins gp160, gp120, gp41 and core protein p24 was evaluated on the in vitro growth of enriched hematopoietic progenitors (CD34+ cells). Both gp120 and gp160, at concentrations from 0.01 to 10 micrograms/ml, caused a progressive and significant (p less than 0.05) decrease in viable CD34+ cell count in liquid cultures supplemented with 2 ng/ml of human recombinant (r) interleukin-3 (IL-3), evaluated by means of Trypan-blue exclusion and [3H]thymidine ([3H]TdR) incorporation. In the absence of rIL-3, no inhibitory effects were observed even at the highest gp160 and gp120 concentrations explored (10 micrograms/ml). On the contrary, gp41 and p24 did not affect the number of viable CD34+ cells, either in the presence or in the absence of rIL-3. Moreover, gp160 and gp120, but not gp41 and p24, significantly (p less than 0.05) inhibited the in vitro growth of granulomacrophage progenitors (CFU-GM) in a dose-dependent fashion. These data clearly demonstrate that HIV-1 envelope glycoproteins inhibit the growth of purified hematopoietic progenitors. We propose that HIV-1 can impair hematopoiesis through the interaction of gp120/gp160 with CD34+ cell surface, independently of an infectious process.
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PMID:Inhibitory effect of HIV-1 envelope glycoproteins gp120 and gp160 on the in vitro growth of enriched (CD34+) hematopoietic progenitor cells. 137 Jun 4

To improve evaluation of new antiretroviral drugs in the acquired immunodeficiency syndrome (AIDS), sensitive biological markers that accurately predict response to treatment are needed. Two possible markers are endogenous interferon (E-IFN), which is a cytokine involved in the pathophysiology of AIDS, and serum triglycerides (TG), which are raised in patients with AIDS, possibly reflecting enhanced cytokine activity. E-IFN, TG, body-mass index, CD4 count, and HIV p24 were measured in 19 patients (15 with AIDS, 4 with AIDS-related complex), who were part of the phase II licensing trial of zidovudine (ZDV). 10 received ZDV and 9 received placebo. Rapid, significant, and sustained declines from initial values in E-IFN and TG concentrations were observed in ZDV patients but not in placebo patients. Baseline values of E-IFN and TG concentrations after 4 months on ZDV treatment were both important contributors to long-term survival. The findings suggest that these indicators of abnormal cytokine expression may be useful measures of not only disease severity but also efficacy of antiretroviral therapy in AIDS.
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PMID:Endogenous interferon and triglyceride concentrations to assess response to zidovudine in AIDS and advanced AIDS-related complex. 134 48

Using recombinant fusion proteins representing different regions of the human Sm B/B' polypeptide, the 4B4 monoclonal anti-Sm antibody was found to bind a C-terminus epitope that is proline-rich. 4B4 cross-reacted with the p24 gag protein of HIV-1 and with other polypeptides rich in proline residues, including collagen. BALB/c mice immunized with human collagen not only produced antibodies to the immunizing antigen but also antibodies to Sm. This immune mouse serum also recognized C-terminus B/B' fusion proteins. These data suggest that the Sm B/B' antigen contains a poly-Pro epitope that is shared by several autoantigens and retroviral proteins. These sites may be important in the induction of autoantibodies through molecular mimicry.
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PMID:Cross-reactivity of the B/B' subunit of the Sm ribonucleoprotein autoantigen with proline-rich polypeptides. 137 27

Human endothelial cells isolated from hepatic sinusoids were infected in vitro with human immunodeficiency virus type 1 (HIV-1). An early sign of infection occurring in the culture was the formation of multinucleated cells. By double-labeling immunofluorescence, 5-15% of the cells recognized as endothelial cells owing to the presence of von Willebrand factor were found to contain HIV p24 and gp120 antigens after 2 weeks. Reverse transcriptase activity was released into the medium, and different steps in the process of viral budding were observed by electron microscopy. The virus produced by the endothelial cells was found to be infectious for CEM cells, a human T-cell line. CD4 molecules are present at the surface of the endothelial cells, as demonstrated by immunogold-silver staining and backscattered electron imaging. Treatment with an anti-CD4 antibody abolished productive infection of the sinusoidal endothelial cells. The possibility that endothelial cells of the liver sinusoid are infected in vivo with HIV remains to be clearly shown.
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PMID:Primary cultures of endothelial cells from the human liver sinusoid are permissive for human immunodeficiency virus type 1. 137 78

Antibodies were determined against five synthetic peptides (epitopes) of HIV-1 p17 in the sera of an immunologically and clinically well-characterized cohort (N = 292) of HIV-1 seronegative and HIV-1 seropositive high-risk homosexual men, HIV-1 seropositive i.v. drug abusers (IVDA), and AIDS patients. The synthetic peptides, representing the entire HIV-1 p17 protein sequence were: HGP-33 (aa 1-33), HGP-19 (aa 34-52), HGP-35 (aa 51-85), HGP-30 (aa 85-114), and HGP-17 ala (aa 114-131). The presence of one or more peptide-specific antibodies in the sera of all of the HIV-1 p17-positive subjects indicated that all five peptides contain B-cell epitopes. No antibodies were found in the sera of heterosexual controls, HIV-1 seronegative high-risk men, or asymptomatic HIV-1 seropositive but p17 antibody-negative study subjects. Significant differences in antibody recognition profiles to the peptide epitopes were found among the various study groups. A significantly higher proportion of HIV-1 seropositive IVDA had antibodies specific to HGP-17 ala (aa 114-131), HGP-35 (aa 51-85), and HGP-33 (aa 1-33) compared to the HIV-1 p17-positive asymptomatic homosexuals. The epitope-specific antibody responses reflected the clinical status of the HIV-1-infected study subjects, and declined to nondetectable levels as the patient progressed to ARC/AIDS. This decline preceded by several months the reduction in the antibody titer against the intact HIV-1 p17 and p24 proteins.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Specific antibody responses to synthetic peptides of HIV-1 p17 correlate with different stages of HIV-1 infection. 137 53

Human fetal thymuses were obtained from abortuses of HIV-1 seronegative females. Thymocytes were isolated and cultured for 2 days with PHA. Thereafter, the culture was divided and half of the cells were exposed to the HIV-1 RF isolate for 4 h. After this incubation period, the HIV-1 exposed and nonexposed control cells were cultured in RPMI 1640 supplemented with IL-2 for 30 days and subsequently maintained in RPMI without the addition of growth factors. Long term culture of both HIV-1 exposed and control thymocytes has yielded two cell lines that have been maintained for more than 3 yr without the addition of growth factors. Flow cytometry using mAb that recognize T cell differentiation markers was used to analyze cell phenotypes. The HIV-1 exposed thymocyte cell line (E88/RF) was shown to be HIV-1 infected by p24 ELISA, reverse transcriptase activity, immunocytochemistry, in situ hybridization, polymerase chain reaction, electron microscopy, and to produce infectious particles by a syncytial forming assay. The non-HIV-1-exposed thymocyte cell line (T412) has remained negative by all criteria for HIV-1 infection. Flow cytometry showed the T412 cells to be positive for the T cell markers CD45, CD38, and CD4 but negative for all other markers tested. The E88/RF cells are positive for CD45 and CD38 but negative for CD4 and other markers. These data report the isolation of two human fetal thymocyte cell lines; one uninfected and susceptible to HIV-1 infection, and the other persistently and productively infected with HIV-1 with little cytopathology. These findings suggest that HIV-1 can persistently infect early T cells and may alter T cell differentiation.
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PMID:Persistent productive HIV-1 infection of a CD4- human fetal thymocyte line. 137 48

A number of studies have suggested that HIV infection can be detected in a variety of routinely fixed archival tissues using antibodies to various viral proteins. In order to study this immunocytochemical approach, paraffin sections were examined with a large panel of commercially available monoclonal antibodies against the various HIV proteins (5 antibodies to p24, 1 to p17, 1 to gp41, and 1 to gp120) using a streptavidin-biotin method. A polyclonal antibody against p24 was also tested. Formalin-fixed, paraffin-embedded HIV infected CEM E5 T cells were used as positive controls. Tissues from AIDS patients included 31 kidneys, 8 lymph nodes, 2 spleens and 3 brains. Non-AIDS tissues examined were 6 renal biopsies with focal segmental glomerulosclerosis, 5 with interstitial nephritis, 6 reactive lymph nodes, and a brain with encephalitis, all from patients not known to be at high risk for HIV infection. Additional negative controls included: 1) replacement of primary antibody with a hybridoma derived mouse monoclonal IgG1 standard, 2) omission of the primary antibody, and 3) sections of formalin-fixed paraffin-embedded CEM E5 T cells cultures not infected with HIV. Competition experiments with excess recombinant p24 protein were also performed. False positive staining with the IgG1 standard or with the antibodies to HIV proteins was frequently seen in tissues with pathologic findings (inflammation, hyalin degeneration), particularly following protein digestion. Protein digestion also had a major impact on specific staining. Digestion with proteinase K abolished specific staining for the core proteins of the virus (p17, p24) on the positive control sections.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Conditions affecting the immunohistochemical detection of HIV in fixed and embedded renal and nonrenal tissues. 137 13

Five monoclonal antibodies (MAbs) were raised against the gag proteins of simian immunodeficiency virus (SIV) from African green monkey (SIVagmTYO-7). Two MAbs reacted with the matrix protein p17 and the other three with the core protein p24. Studies on the cross-reactivity of the MAbs revealed that the anti-p24 MAbs detected an epitope shared by the viruses belonging to the human immunodeficiency virus type 2 (HIV-2)/SIVmac group and SIVagmTYO-7 and SIVagmTYO-5. The anti-p17 MAbs recognized an epitope present on all these viruses and on SIVagmTYO-1, HIV-1 and SIVmnd. This finding demonstrates for the first time that the matrix protein, p17 or p18, respectively, of all nine HIV and SIV isolates tested in this study expresses at least one conserved immunogenic epitope recognized serologically. By using synthetic peptides, this epitope was identified at the N terminus of p17. Furthermore, this epitope was analysed by multiple sequence alignments of the peptide with homologous sequences of HIV and SIV p17.
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PMID:Identification of a gag protein epitope conserved among all four groups of primate immunodeficiency viruses by using monoclonal antibodies. 138 99

Linear B cell epitopes were mapped on the major core protein p24 of human immunodeficiency virus type 1 (HIV-1), simian immunodeficiency virus (SIVAGM) and feline immunodeficiency virus (FIV) using a fusion protein-based method and murine monoclonal antibodies reactive against the p24 antigens expressed on the surface of HIV-1- and FIV-infected cells. The results suggest that the sites identified here are encoded at similar positions in the three virus genomes and consist of highly conserved epitopes, which could exhibit immunodominance.
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PMID:Highly conserved epitope domain in major core protein p24 is structurally similar among human, simian and feline immunodeficiency viruses. 138 11

A panel of 20 recombinant Fab fragments reactive with the surface glycoprotein gp120 of human type 1 immunodeficiency virus (HIV-1) were examined for their ability to neutralize MN and IIIB strains of the virus. Neutralization was determined as the ability of the Fab fragments to inhibit infection as measured in both a p24 ELISA and a syncytium-formation assay. One group of closely sequence-related Fab fragments was found to neutralize virus in both assays with a 50% neutralization titer at approximately 1 micrograms/ml. Another Fab neutralized in the p24 ELISA but not in the syncytium assay. The other Fab fragments showed weak or no neutralizing ability. The results imply that virion aggregation or crosslinking of gp120 molecules on the virion surface is not an absolute requirement for HIV-1 neutralization. Further, all of the Fab fragments were shown to be competitive with soluble CD4 for binding to gp120 and yet few neutralized the virus effectively, implying that the mechanism of neutralization in this case may not involve receptor blocking. The observation of a preponderance of high-affinity Fab fragments with poor or no neutralizing ability could have implications for vaccine strategies.
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PMID:Recombinant human Fab fragments neutralize human type 1 immunodeficiency virus in vitro. 138 50


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