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

Because cytokines have a central role in the regulation and function of the human immune system, expression of several key cytokine genes in HIV infection was compared by quantitative polymerase chain reaction studies in lymphocytes from HIV-seronegative and -seropositive subjects. Elevated levels of IFN-gamma mRNA and lowered IL-2 mRNA were found in the PBMC of eight seropositive men with CD4 T cells over 500/mm3 (mean, 647/mm3), whereas IL-4 and IL-10 mRNA were not changed significantly. PBMC obtained 2 yr later from four of these patients with stable disease status (unchanged CD4 T cell number) showed median mRNA levels that were nearer normal for IFN-gamma and for IL-2. Four other men whose CD4 levels fell more than 200/mm3 in the following 2 yr, however, showed increased IFN-gamma and lowered IL-2. Purified CD4 and CD8 T cells from 10 HIV-seropositive and 10 -seronegative homosexual men were compared. Cytokine gene expression was found to be markedly different in CD4 and CD8 T cells from HIV-seropositive men. In CD8 T cells on a per-cell basis, the levels of cytokine mRNA were substantially lower than in CD4 T cells and were not markedly changed in HIV infection. In the CD4 T cells, on a per-cell basis, the mean mRNA levels of IFN-gamma, IL-10, and TNF-alpha were increased substantially (p < 0.001) in HIV infection. IL-2 gene expression was not increased significantly. Thus, the low IL-2 mRNA expression seen in PBMC is primarily due to the reduced CD4 T cell numbers. Increased expression of IFN-gamma genes in CD4 T cells, however, indicates that these cells may be responsible for substantial amounts of circulating IFN-gamma that occur in HIV infection. The striking difference in the effect of HIV infection on the expression of IFN-gamma and IL-2 genes indicates that these cytokines are under separate control. IL-4 mRNA levels were not changed. IL-10 gene expression, however, was increased more in early HIV infection, with less of an increase later. Expression of all cytokines in CD4 T cells appeared to subside late in HIV infection. However, the balance of cytokine expression was altered in all stages of HIV infection.
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PMID:Elevated IFN-gamma and decreased IL-2 gene expression are associated with HIV infection. 840 54

The injection of DBA/2 parental lymphocytes into adult, immunologically intact (C57BL/6 x DBA/2) F1 hybrid mice results in a chronic graft-vs-host reaction (GVHR) characterized by a deficiency in CD4+ T cell functions and a B cell activation leading to autoantibody production. The discovery that distinct subpopulations of Th cells may regulate the effector immune functions led us to investigate whether the chronic GVHR differentially affects Th subsets. Data are presented indicating that mice undergoing a GVHR spontaneously produced lymphokines of Th2 origin. IL-4 and IL-10 mRNA were detected in the spleens of GVH mice, and IL-4 was shown to be responsible for the increased expression of class II Ag on B cells. Moreover, upon polyclonal activation in vitro, GVH T cells exhibited defective IL-2 and IFN-gamma production but elevated IL-4 production. We conclude that the chronic GVHR is characterized by a selective deficiency in cells secreting IL-2 and IFN-gamma and a hyperactivation of Th2 cells. The simultaneous production of IL-4 and IL-10 might explain the association between B cell hyperactivity and impairment of Th1-like activities in various models that associate autoimmunity and immunosuppression, such as GVHR and HIV infection.
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PMID:Preferential activation of Th2 cells in chronic graft-versus-host reaction. 841 69

Infection with HIV results in an incremental loss of T helper cell (TH) function, which can occur years before CD4 cell numbers are critically reduced and AIDS is diagnosed. All TH function is not affected, however, because B cell activation and hypergammaglobulinema are also characteristic of this period. Recently, in a murine model of AIDS an early loss in production of the CD4 cytokines IL-2 and IFN-gamma was correlated with an increase in the B cell stimulatory cytokines IL-4, IL-5, and IL-10. We therefore assessed the production of IL-4 generated by PBL from HIV-seropositive (HIV+) individuals who did not have AIDS, yet who exhibited different TH functional categories based on their IL-2 production profiles. We observed that the decreases in recall antigen-stimulated IL-2 production were accompanied by an increase in IL-4 production. The loss of recall antigen-stimulated responses in HIV+ individuals could be reversed in vitro by anti-IL-4 antibody. Our results suggest that the TH functions assessed by IL-4 production replace the normally dominant TH function of antigen-stimulated IL-2 production in the progression toward AIDS, and raise the possibility of cytokine cross-regulation in AIDS therapy.
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PMID:Changes in interleukin-2 and interleukin-4 production in asymptomatic, human immunodeficiency virus-seropositive individuals. 845 57

The HIV envelope glycoprotein gp160 has been previously demonstrated to induce differentiation of normal B lymphocytes into Ig-secreting cells; the response is T cell-dependent, and T cells pretreated with gp160 can support B cell differentiation. This study investigates the cell surface molecules and cytokines that play a role in the gp160-induced T-B cell interaction. Utilizing CD4+CD45RO+ cloned T cells as the source of helper cells, we observed that physical contact with B cells is essential for the gp160-induced B cell response; no IgG-secretion occurred if T cells were separated from the B cells by culturing them in Transwell chambers. The expression of T cell-B cell activation molecule, a novel surface molecule associated with T cell activation, was moderately increased by gp160, and antibody to T cell-B cell activation molecule abrogated the gp160-mediated Th cell function. Cell surface molecules LFA-1, ICAM-1, HLA-DR, CD28, and B7 were also involved in the T-B cell interaction since mAb to any of these molecules inhibited the gp160-induced B cell differentiation response. gp160 also induced IL-6R and CD23 molecule expression on B cells when added to cultures of T plus B cells; there was CD23 expression only in cells that formed conjugates with T cells. Paraforamaldehyde-fixed, gp160-pretreated T cells failed to elicit IgG responses in B cells, but did induce CD23 and IL-6R up-regulation on B cells. Addition of exogenous IL-6, but not IL-2 or IL-4, restored the IgG secretion. These findings indicate that the T cell dependence for gp160-induced B cell differentiation responses involves two steps: one requires contact-dependent interaction of several cell surface molecules, and the second requires IL-6 secretion.
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PMID:HIV-gp 160-induced T cell-dependent B cell differentiation. Role of T cell-B cell activation molecule and IL-6. 845 Feb 24

Polyclonal B cell activation is characteristic of HIV infection and occurs in the presence of severe CD4+ lymphocyte depletion. In contrast, CD4+ lymphocytes are the dominant T cell in the reactive lymphoid tissues of patients not infected with HIV. In this study, lymph node biopsies from eight HIV-infected patients with persistent generalized lymphadenopathy syndrome (PGL) were assessed for IL-1 beta, IL-2, IL-4, IL-6, IL-10, interferon-gamma (IFN-gamma) and tumour necrosis factor-beta (TNF-beta) gene expression using the polymerase chain reaction (PCR). The cytokine gene expression of two cases of reactive adenopathy in patients not infected with HIV was assessed for comparison. IFN-gamma was expressed much more strongly in the PGL samples than in control reactive lymphoid tissues, whereas the other cytokines were expressed to a similar extent in both types of tissues. IFN-gamma may have an important role in maintaining the adenopathy of HIV-infected patients. Expression of cytokines such as IL-2, IL-4 and IL-10 in HIV nodes may be adequate to allow the recruitment of naive B cells to the reactive process.
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PMID:Increased expression of interferon-gamma in hyperplastic lymph nodes from HIV-infected patients. 846 56

The transactivating nuclear factor NF-kappa B is believed to be important in the pathophysiology of many cellular systems and mainly during HIV infection. kappa B activation has also been implicated in the process of differentiation as a cell progresses to a more mature and functional stage. As induction of differentiation equals growth retardation we undertook this study in order to establish the role of NF-kappa B in cell growth and maturity. Thus we employed the well described HL-60 cellular system that expresses constitutively basal amounts of NF-kappa B and is susceptible to NF-kappa B induction by various biological or chemical agents. We also used known inducers of differentiation like TNF-alpha, IFN-gamma and IL-4 that interact via their corresponding surface receptors found on HL-60 cells. We first studied by Northern analysis the possible correlation between c-myc and NF-kappa B precursor (p105) mRNA. We witnessed that all three cytokines were able to confer proliferative senescence and down-regulate concomitantly c-myc and NF-kappa B mRNA levels, events chronologically in accord with induction of differentiation as assessed by the induction of HLA-DR surface antigens. It is known that TNF-alpha is capable of inducing nuclear kappa B activity in HL-60 as the cells progress to a more mature stage. Therefore we examined whether the other two cytokines could do the same during the time they lead the cells to a differentiated phenotype. If this was the case, nuclear activation of NF-kappa B should be obtained by the same factors.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:One and two-level regulation patterns affecting NF-kappa B mRNA and nuclear NF-kappa B activity after treatment with TNF-alpha, IFN-gamma and IL-4. 849 Jan 2

The thymus is essential for normal T cell development and is particularly active during fetal and postnatal life. Here we describe in vitro studies of HIV-infected thymocytes cultured with cytokines normally produced in the thymus. Virus expression was determined by measuring p24 antigen levels in the culture supernatants. Addition of IL-2+IL-4 and IL-4+IL-7 to the HIV-infected cultures of both fetal and postnatal thymocytes resulted in various levels of synergistic expression of p24 antigen. When differences in phenotype between HIV-infected and non-infected (sham-treated) cultures from the same specimen were evaluated, there was a decrease in the percentages and absolute numbers of CD4-bearing cells in HIV-infected thymocytes cultured with IL-2+IL-4. Studies were done to determine if synergy in HIV expression was mediated by activation, proliferation or induction or suppression of other cytokines. We found a higher percentage of activated CD4+CD8+/high cells in thymocytes cultured with IL-2+IL-4 and IL-4+IL-7 than in thymocytes cultured with IL-2+IL-7. Proliferation was higher in thymocytes cultured with cytokine combinations but did not correlate with those conditions showing synergy. IL-4 reduced IFN-gamma production by thymocytes cultured with IL-2 in both HIV-infected and non-infected thymocytes. In addition, exogenous IFN-gamma decreased p24 expression by HIV-infected thymocytes when cultured with IL-4 alone, with IL-2+IL-4 or IL-4+IL-7. These results suggest that suppression of IFN-gamma by IL-4 may combine with cell activation and proliferation to produce synergy of virus expression observed with IL-2+IL-4 and IL-4+IL-7.
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PMID:Effects of cytokines on HIV-1 production by thymocytes. 852 3

An in vitro culture system was developed that facilitates detailed studies of the interaction of Human Immunodeficiency Virus (HIV) with dendritic cells (DC). Cultured immature DC were generated from adherent peripheral blood mononuclear cells in the presence of GM-CSF and IL-4. These cells were non-adherent, non-phagocytic and had a veiled surface appearance. They expressed high levels of MHC class I and II proteins, CD1a, B7/BB1 and low levels of CD4, and were known to possess a potent soluble antigen presenting capacity. Upon infection with the HIV-1 strains Lai (lymphocytotropic) and BaL (monocytotropic), the viral RNA was reverse transcribed to complete DNA provirus. However the infection was non-productive as judged from measuring the activity of the virus encoded reverse transcriptase in the culture supernatant. Thus HIV infection was restricted at a step post entry.
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PMID:Infection of cultured immature dendritic cells with human immunodeficiency virus type 1. 852 22

Expression vectors encoding either HIV-1 gp160/rev, gp120, or rev alone were used for direct vaccination of mice and nonhuman primates. Each vaccine elicited long-lived (> 7 months) helper T cell responses in mice and monkeys as measured by in vitro proliferation of splenocytes following recombinant antigen treatment. Cytokine assays of the cell supernatants showed that approximately 100-fold more gamma-interferon than IL-4 was secreted during culture indicating that these vaccines elicited TH1-like responses. CD8+ CTL activities were also observed both in mice and rhesus. The gp120 and gp160/rev vaccines elicited antigen-specific antibodies, although these responses were more variable and lower magnitude for gp160/rev, and gp120 DNA-vaccinated African green monkeys had moderate levels of neutralizing antibodies. No antibodies were found against rev (an intracellular protein) with either rev vaccine. Similar antibody titers were obtained for gp120 by either intramuscular or intradermal injection although T cell responses were generally lower by intradermal route. These results indicate that DNA vaccines may provide a powerful means to elicit cellular and humoral immune responses against HIV.
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PMID:Cytotoxic T lymphocyte and helper T cell responses following HIV polynucleotide vaccination. 854 93

The infectious disease background and particularly the helminth infections that are endemic in Africa could have profound effects on the host immune system. Studies that we have performed on an Ethiopian HIV- immigrant population that has recently reached Israel, lend support to this notion. They have indeed revealed a very high prevalence of helminth and several other infections with an extreme immune dysregulation, consisting of: (i) highly elevated plasma IgE, IgG, placental isoferritin, p75 soluble TNF receptor (sTNFR) levels and very high blood eosinophilia; (ii) increased secretion from phytohaemagglutinin (PHA)-simulated peripheral blood mononuclear cells (PBMC) of the cytokines IL-2, IL-4, IL-10 and p75 sTNFR, and decreased secretion of interferon-gamma (IFN-gamma) and IL-6; (iii) increased and decreased surface expression of p75 TNFR and IL-6 receptor on lymphocytes, respectively. The causal relationship between this immune dysregulation and the infectious background is highly suggestive, and could have far-reaching implications in the resistance to other infections.
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PMID:Immune dysregulation in Ethiopian immigrants in Israel: relevance to helminth infections? 856 6


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