Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

CTL and antibody responses to HIV-1 p17 and p24 antigens were monitored from 1986-1991, in 4 hemophiliacs. The patients had been infected with HIV-1 between 1980 and 1984. Two patients have remained asymptomatic while two progressed to AIDS in 1990. CTL were boosted by culturing with peptides from p17 aa 86-115, or p24 aa 265-279; and aa 270-373 or PHA. Lysis was measured on autologous or allogeneic targets pulsed with peptides or infected with recombinant vaccinia virus carrying HIV-1 gag or influenza A matrix genes. Antibodies to p17 and p24 were tested by ELISA using peptides and by Western blotting. High levels of CTL activity to p17 and p24 antigens could be generated only with lymphocytes from the two asymptomatic patients between 1986 and 1989, but these responses were absent in 1990 and 1991. Antibodies to p17 peptides disappeared in parallel with CTL activity. Antibodies to some p24 peptides also declined but most patients retained activity to others. In all patients a > or = 3-fold increase in CD8+ cell numbers occurred over time and accompanied the decline of CTL and antibody responses. The loss of CTL and p17 antibodies occurred irrespective of whether patients remained asymptomatic or progressed to AIDS in the intervening two years.
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PMID:Decline in CTL and antibody responses to HIV-1 p17 and p24 antigens in HIV-1-infected hemophiliacs irrespective of disease progression. A 5-year follow-up study. 128 55

Adherent cells from HIV-infected subjects as well as in vitro HIV-infected normal adherent cells produce spontaneously a 29-kD (p29) factor that inhibits mitogen-induced proliferation of normal T cells. p29 mediates a partial dose-dependent inhibition of total protein synthesis in both nonstimulated and PHA-activated cells that is associated with impaired PHA-induced expression of IL-2 receptor (IL-2R)alpha chain, HLA-class II molecules, and production of IL-2 by these cells; conversely, p29 does not modify the expression of IL-2R beta chain, 4F2, CD9, or transferrin receptor, or the production of IL-1 and TNF alpha by the cells. 1 h preincubation of the cells with p29 is sufficient to detect its biologic activity and added rIL-2 abrogates p29-induced inhibition of IL-2R alpha chain expression; however, p29 does not display any biologic effect on already expressed IL-2R alpha chains. The impaired expression of IL-2R alpha chain mediated by p29 is not due to a decreased accumulation of the corresponding mRNA transcripts, but is associated with a two-fold increase of intracellular cAMP. Binding experiments with 125I-rIL-2 reveals that p29 induces a 50% decrease in the number of both high and low affinity IL-2R per cell. p29 also inhibits alloantigen-induced proliferation of PBMC, whereas it does not modify IL-2-dependent proliferation of 48-h PHA-blasts that already express high affinity IL-2R. These findings indicate that p29 mediates its biologic activity during early stages of T cell activation affecting the expression of high affinity IL-2R and production of IL-2, through a nontranscriptional mechanism involving an increase of intracellular cAMP.
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PMID:Human immunodeficiency virus-infected adherent cell-derived inhibitory factor (p29) inhibits normal T cell proliferation through decreased expression of high affinity interleukin-2 receptors and production of interleukin-2. 132 45

The CTL response to HIV-1 is more vigorous than for any known human pathogen and may be a significant factor in preventing the progression to symptomatic disease. T cell lines, generated by non-specific stimulation with PHA and IL-2, may be reproducibly used to identify HIV-1 isolate-invariant epitopes recognized by the CTL of infected individuals. The CTL response in each of 12 infected individuals to envelope and reverse transcriptase (RT) is dominated by the recognition of one or two viral isolate-invariant epitopes. Seven subjects respond to a single gp160 epitope; three subjects recognize 2 gp160 epitopes. There is a significant increase in recognition of epitopes in the C terminal 104 amino acids of gp41 (p less than 0.002); in fact 40% of the subjects that respond to gp160 recognize the C terminal 20-mer. The CTL-mediated lysis of gp160-expressing targets is MHC restricted, but not all individuals that share the same serologically defined class I-restricting element respond to the same epitope. Recognition of the terminal 20mer is restricted by both A30 and B8. The response to RT in six subjects is distributed over the RT protein. The six subjects recognize four separate regions defined by truncated RT-vaccinia recombinants, but none of the subjects' CTL demonstrate significant recognition of the RT epitope identified in H-2k mice and some humans.
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PMID:Cytotoxic T lymphocytes from HIV-1 seropositive individuals recognize immunodominant epitopes in Gp160 and reverse transcriptase. 137 97

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

The CD25 (IL-2-R alpha) cell surface glycoprotein expressed transiently during T-cell activation is implicated in the high affinity IL-2 receptor. This paper shows that cell-free supernatants from chronically HIV-infected promonocytic cells spontaneously produce a soluble factor which inhibits CD25 expression on PHA-activated human PBMC. We purified the CD25 expression inhibitory activity by a factor 12,350, using XM50 ultrafiltration, Superose 12 molecular sieving chromatography and MonoQ anion-exchange chromatography. Then we associated this activity to one single spot (M(r) 29,000, pI 6.8) on an O'Farrell two-dimensional gel. Our data demonstrate that this protein (M(r) 29,000, pI 6.8) is released from HIV-infected promonocytic cells and suggest that this factor is a new monokine regulating the T-cell activation process.
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PMID:Purification and identification of a CD25 expression inhibitory protein from cell-free supernatants of chronically HIV-infected promonocytic cells. 151 55

By using a fluorescence sandwich ELISA for the quantification of soluble human IL-6R, normal human PBMC were found to be induced to release IL-6R into culture supernatant by stimulation with PHA. Furthermore, certain promonocyte cell lines and human T-cell leukemia virus I (HTLV-I)-positive cell lines produced sIL-6R into culture supernatants constitutively. However, this was not found with HTLV-I negative T cell lines and Burkitt's B cell line. In addition, generation of supernatant IL-6R of the promonocyte cell line was significantly increased 27-fold after PMA treatment and sevenfold after infection with HIV. The released IL-6R molecules were characterized as an apparent m.w. of 50 to 55 kDa by both size-exclusion HPLC and immunoprecipitation of the soluble protein with IL-6R-specific mAb followed by SDS-PAGE analysis. Furthermore, increased levels of serum IL-6R were detected in blood donors seropositive for HIV. Moreover, the released IL-6R could bind efficiently to purified rIL-6 on solid phase and suppressed the proliferative responses of PBMC. These results suggest that the release of soluble IL-6R might be linked to regulatory functions of immune responses induced by IL-6 stimulation during normal and human retrovirus-infected cell growth and differentiation.
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PMID:Human soluble IL-6 receptor: its detection and enhanced release by HIV infection. 154 25

Human T cells express HLA class II molecules upon activation. The factors that regulate the induction of expression of these molecules are for the most part unknown. Here we report preliminary results indicating that tumor necrosis factor-alpha (TNF-alpha) regulates the induction of cell-surface HLA-DR, DO, and DP molecules in human T cells stimulated with PHA. In contrast, recombinant interferon-gamma (rIFN-gamma), recombinant interleukin-1 alpha (rIL-1 alpha), or rIL-4 appear to have no effect on class II expression. The role of class II molecules on activated T cells is discussed in relationship to immunoregulation and the progression of HIV infection. Three non-mutually exclusive hypotheses are discussed. In the first hypothesis, we consider the role of these class II molecules in antigen presentation of endogenously synthesized HIV envelope by CD4+ cells. The second is a clonal inactivation of virus-specific helper T cells that might occur as a consequence of a direct T cell to T cell interaction and a bypass of the "accessory signal" normally delivered by antigen-presenting cells such as macrophages. The third is a molecular mimicry between HIV envelope proteins and HLA class II molecules, which may lead to the development of autoimmunity against CD4+ T-cell-expressing class II molecules.
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PMID:Induction of HLA class II molecules on human T cells: relationship to immunoregulation and the pathogenesis of AIDS. 156 60

The Toronto Sexual Contact Study comprises a cohort of 249 male sexual contacts of men with HIV disease which has been followed every 3 months for almost 5 years. On enrollment 143 were seropositive and 16 seroconverted during the follow-up period. By 31 December 1989, 41 of the 159 seropositive cohort members had developed AIDS. Using Cox relative risk regression models, we investigated the association of a number of laboratory and clinical variables and progression to AIDS. Fixed covariate models examined laboratory variables from the enrollment visit of cohort members, with time calculated from this date. In models assessing time dependent covariates, time was calculated from the estimated date of HIV infection. In the univariate models of either fixed or time dependent covariates, many variables were significantly associated with risk of progression to AIDS (T4 cell count, T4/T8 ratio, blastogenic responses to phytohemagglutinin, concanavalin A, and pokeweed mitogen, serum IgA, appearance of p24 antigen, and the development of oral hairy leukoplakia, thrush, or herpes zoster). Appearance of persistent generalized lymphadenopathy was not associated with increased risk of progression. In the multivariate model which evaluated fixed laboratory covariates, T4/T8 ratio, IgA level, and PHA response at enrollment were significantly associated with elevated risk.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Using serial observations to identify predictors of progression to AIDS in the Toronto Sexual Contact Study. 156 21

Eleven (nine CD4+ and two CD8+) protein purified derivative-specific and eight tetanus toxoid-specific T cell clones (TCC), established from the peripheral blood of healthy persons, were cocultured in vitro with irradiated mononuclear cells from patients infected by HIV in the presence of PHA and polybrene. Two weeks post-HIV exposure, all 17 CD4+, but neither of the two CD8+, TCC exhibited integration of HIV in their genoma, as detected by polymerase chain reaction analysis, and released HIV into their supernatants, as detected by measuring both reverse transcriptase activity and p24 Ag. When co-cultured with either autologous or allogeneic B cells, all CD4+ HIV-infected TCC induced the synthesis of extraordinarily high amounts of IgM, IgG, and IgA. In contrast, their noninfected counterparts could provide helper function for Ig synthesis by autologous B cells only in the presence of the specific Ag (or anti-CD3 antibody), and induced allogeneic B cells to synthesize Ig only upon stimulation with anti-CD3 antibody. The supernatants of HIV-infected TCC failed to stimulate Ig synthesis in B cells. More importantly, when HIV-infected clonal T blasts and B cells were cultured in different chambers separated by a millipore membrane, permeable to molecules but not to cells, Ig synthesis did not occur. The Ig synthesis induced by HIV-infected TCC was also markedly inhibited by the addition in culture of either anti-CD4 or anti-LFA-1 antibody. In contrast, HIV-infected TCC maintained their ability to provide helper function for Ig synthesis in the absence of any stimulus, even after fixation with p-formaldehyde. These data demonstrate that in vitro infection with HIV enables human T cells to stimulate Ig synthesis by B cells by an Ag-nonspecific, MHC-unrestricted, contact-dependent mechanism. This may explain, at least in part, the hypergammaglobulinemia and other phenomena related to polyclonal B cell activation frequently seen in HIV-infected persons.
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PMID:In vitro infection with HIV enables human CD4+ T cell clones to induce noncognate contact-dependent polyclonal B cell activation. 167 84

The effects of long-term zidovudine treatment on functional parameters of cell-mediated immunity were investigated in 15 symptomatic HIV-antibody-positive patients with clinical evidence of opportunistic infections. Mononuclear leukocytes were obtained before administering the drug, and after 3 and 6 months of treatment. The cells were stimulated with lectins in order to assess variations of mitogen-induced lymphocyte proliferation and production of gamma-interferon (IFN) and interleukin-2 (IL-2), and with Newcastle disease virus (NDV) to assess variations of alpha-IFN production. Mean proliferative responses to PHA and Con-A did not show any significant change between baseline, 3 months, and 6 months values (25,158 +/- 11,763, 24,662 +/- 8,955, and 34,924 +/- 16,283 D-cpm, respectively, for PHA, p greater than 0.05; and 5,470 +/- 1,890, 4,953 +/- 2,518, and 4,539 +/- 3,286 D-cpm, respectively, for Con-A, p less than 0.05). Mean response to PWM (9,707 +/- 4,429 D-cpm at entry) increased significantly after 3 months, but returned to baseline values at 6 months (17,039 +/- 5,123 and 10,314 +/- 3,855 D-cpm, respectively, p = 0.016). IL-2 production (5.51 +/- 4.0 I.U. at entry) rose particularly at 3 months and persisted at the same levels at 6 months (9.6 +/- 4.8 and 9.5 +/- 6 I.U., respectively, p less than 0.05). By contrast, a moderate but significant decrease in gamma- and alpha-IFN production was observed (65 +/- 2.2, 35.1 +/- 1.6, and 22 +/- 2 I.U., respectively, for gamma-IFN, p less than 0.05; 60 +/- 3, 64 +/- 2.6, and 12 +/- 1.5 I.U., respectively for alpha-IFN, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of long-term zidovudine treatment on cell-mediated immune response and lymphokine production. 170 62


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