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Query: UMLS:C0001175 (AIDS)
 120,706 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The potential for eliciting humoral and cytotoxic T lymphocyte (CTL) responses to HIV-1 gp120 by gene gun-based DNA immunization in mice was examined. We speculated that the induction of de novo antigen production in the epidermis of BALB/c mice following particle bombardment-based gene delivery would result in both MHC class I- and class II-mediated antigen presentation for the elicitation of CTL and antibody responses, respectively. Following epidermal delivery of microgram quantities of an expression plasmid, gp120 production resulted in the appearance of MHC class I-restricted, CD8+ CTL responses. gp120-specific CTL responses peaked following a booster immunization, then declined with the appearance of gp120-specific IgG responses when additional booster immunizations were administered. This qualitative progression in the nature of gp120-specific immune responses with subsequent immunizations was paralleled by a simultaneous shift in the interferon-gamma and interleukin 4 release profiles following antigen stimulation of splenocytes in vitro. The simultaneous shifts in immune responses and cytokine release profiles indicate that the progression of antigen-specific CTL and IgG responses in gp120 DNA-immunized mice may be mediated through changes in the in vivo production of cytokines, such as those associated with the Th1 and Th2 subsets of CD4+ cells.
AIDS Res Hum Retroviruses 1994 Nov
PMID:A qualitative progression in HIV type 1 glycoprotein 120-specific cytotoxic cellular and humoral immune responses in mice receiving a DNA-based glycoprotein 120 vaccine. 788 98

A gradual reduction in cell-mediated immunity is thought to occur with the progression of human immunodeficiency virus (HIV) infection. This suggests a selective attrition of the Th1 subset. The regulation of the soluble form of the low-affinity receptor for IgE (sCD23) by the opposing actions of interleukin-4 (IL-4) and interferon-gamma (IFN-gamma) allows the assessment of the overall balance of Th1 to Th2 activity in a given disease. In order to investigate this further we employed an enhanced chemiluminescent ELISA to analyse serum levels of sCD23 in male subjects with and without HIV infection. Serum levels of sCD23 were similar in 34 HIV seronegative homosexuals, 39 homosexuals with asymptomatic HIV infection, 27 homosexuals with acquired immune deficiency syndrome (AIDS) and 20 healthy controls. This suggests that HIV has no predilection for either the Th1 or Th2 subsets of CD4 T cells.
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PMID:Serum measurements of soluble CD23 in HIV infection. 790 61

AIDS typically consists of three phases: (1) an acute, infectious mononucleosis-like syndrome followed by (2) a prolonged asymptomatic stage ending in (3) the appearance of frank AIDS. The asymptomatic phase may last for years and its presence suggests a persistent conflagration between the virus and the host's immune response. There is considerable evidence that an immune response develops but the response is ultimately inadequate. From the work of others as well as our own, we have constructed a hypothesis which attempts to explain some aspects of the immune response. We propose that HIV-1 preferentially infects a subset of CD4+ lymphocytes which are then either destroyed or altered in their biological functions. Further, we suggest that this subset represents the CD4+ TH1 lymphocyte population. By decreasing the quantity of IL-2 and interferon-gamma produced by TH1 lymphocytes, the production of cytokines by TH2 cells is increased. One of the cytokines produced by TH2 lymphocytes is IL-10, a polypeptide with significant inhibitory properties towards lymphocytes. Sera from patients with frank AIDS have significant lymphocyte inhibitory activities some of which operate through IL-10. Thus, a gradual shift to a TH2-type response and release of increasing amounts of inhibitors eventually prevents the host from replacing destroyed cells or mounting new and appropriate immune responses.
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PMID:Breaking the asymptomatic phase of HIV-1 infection. 791 Jun 37

We assessed correlations between body mass index and plasma lipids, immune activation markers and the CD4+ T-cell count. The subjects of this cross-sectional study were randomly selected and comprised all those who attended the AIDS Out-Patient Clinic at the University Hospital in Innsbruck in March and April 1992. Patients with signs and symptoms of acute bacterial and secondary opportunistic infections were excluded. We investigated 63 individuals with HIV infection of whom 35 were asymptomatic, 8 had oral candidiasis, 4 had constitutional signs and symptoms and 16 had AIDS, for an association among body mass index, urinary neopterin, soluble tumor necrosis factor receptors (sTNFRs), plasma lipids, and the numbers of CD4+ T cells. The body mass index correlated inversely with urinary neopterin (rs = -0.42, p = 0.0009) and weakly with the numbers of CD4+ T cells (rs = 0.29, p = 0.02) but not with plasma lipids, sTNFRs and beta 2-microglobulin. The results show that body mass index correlates with immune activation. The data suggest that endogenous formation of interferon-gamma may be an important mediator of wasting in HIV infection, since this cytokine is responsible for the observed elevation of neopterin concentrations in body fluids.
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PMID:Correlation of body mass index with urinary neopterin in individuals infected with human immunodeficiency virus. 791 Oct 45

We measured levels of soluble intercellular adhesion molecule 1 (sICAM-1) in paired serum and CSF samples of 110 HIV-1-positive patients with and without neurological symptoms and 40 HIV-negative non-immune neurological controls, and in sera of 26 asymptomatic HIV-1-positive patients. Serum sICAM-1 levels in asymptomatic HIV-1-positive patients were significantly increased in comparison to HIV-negative controls. Moreover, they were significantly higher in HIV-1-positive patients with AIDS-defining diseases than in the asymptomatic HIV-1-positive group. In subgroups of patients with neurological disease, the highest serum values were found in HIV encephalopathy. CSF levels of sICAM-1 were elevated only in HIV-1-positive patients with neurological disease mainly due to passive diffusion through a defective blood-brain barrier. An sICAM-1 index was calculated as a measure for intrathecal production of sICAM-1 but showed no significant differences between patients with and without neurological involvement. However, increased levels of the sICAM-1 index were found in some patients with opportunistic CNS infection of bacterial or fungal origin. Serum and CSF levels of sICAM-1 correlated with neopterin levels, a marker of interferon-gamma-mediated macrophage activation and CSF sICAM-1 levels were inversely correlated to numbers of CD4+ T cells. Elevated serum sICAM-1 levels already in asymptomatic HIV-1-positive individuals add to the evidence for an early immune activation in HIV infection. With the further increase of serum and CSF s-ICAM-1 in patients with AIDS-defining diseases sICAM-1 could serve as a new surrogate marker similar to neopterin.
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PMID:Serum and cerebrospinal fluid levels of soluble intercellular adhesion molecule 1 (sICAM-1) in patients with HIV-1 associated neurological diseases. 791 74

Female C57BL/6 mice were infected with LP-BM5 retrovirus, causing murine AIDS, which is functionally similar to human AIDS. Vitamin E effects on immune functions, cytokine production and nutritional concentrations in retrovirus-infected mice were determined. Retrovirus infection inhibited release of interleukin-2 (IL) and interferon-gamma (IFN) and some immune functions, whereas it stimulated secretion of IL-4, IL-5, IL-6 and tumor necrosis factor-alpha (TNF) and immunoglobulin (Ig) production. Furthermore, retrovirus infection induced some nutritional deficiencies in the tissues. A 15-fold increase in dietary vitamin E largely restored concentrations of some micronutrients (vitamins A and E, zinc and copper) in the liver, intestine, serum and thymus. It also partially restored production of IL-2 and IFN-gamma by splenocytes. Retrovirus-induced elevated production of IL-4, IL-5 and IL-6 by splenocytes in vitro was normalized by vitamin E. Elevated release of IL-6, TNF-alpha, IgA and IgG produced by splenocytes in vitro during murine AIDS were also completely or partially normalized by vitamin E. Vitamin E also prevented retrovirus-induced suppression of splenocyte proliferation and natural killer cell activity. These data indicate that vitamin E supplementation during murine AIDS can help to ameliorate the disorders during murine AIDS, suggesting vitamin E usefulness in treatment of AIDS in humans.
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PMID:Nutritional status and immune responses in mice with murine AIDS are normalized by vitamin E supplementation. 793 12

Female C57BL/6 mice were infected with LP-BM5 retrovirus, causing murine AIDS which is functionally similar to human AIDS. Retrovirus infection targets the thymus producing altered T-cell differentiation via the dysregulation of thymocyte cytokine production. Therefore the effects of dietary vitamin E at various levels were determined on cytokine production by ConA-stimulated thymocytes from uninfected (normal) and retrovirus-infected mice. Dietary supplementation, with a 15-, 150- and 450-fold increase of vitamin E in the diet modulated interleukin-2 (IL) production in both uninfected mice and retrovirus-infected mice. The 150- and 450-fold vitamin E supplementation significantly reduced IL-4 secretion by thymocytes from the uninfected, normal mice. Supplementation at all levels also significantly reduced IL-4 production by thymocytes, which was elevated by the retrovirus infection. Vitamin E significantly reduced IL-6 and interferon-gamma production increased during the progression to murine AIDS. The effects of dietary vitamin E on conA-induced proliferation of thymocytes were consistent with the finding on changes of IL-2 secretion. No effect of dietary vitamin E on thymus weight was observed in both uninfected and retrovirus-infected mice. These data indicate that dietary vitamin E supplementation at extremely high levels can modulate cytokine production by thymocytes. This could affect T-cell differentiation, especially during murine AIDS when cytokine production was partially normalized by vitamin E supplementation.
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PMID:Vitamin E supplementation at various levels alters cytokine production by thymocytes during retrovirus infection causing murine AIDS. 794 Jun 43

Neopterin is a pteridine produced by human mononuclear phagocytes, usually in response to interferon-gamma (IFN-gamma) stimulation. Increasing serum levels of neopterin correlate with clinical progression to AIDS in HIV-infected people, but the factors that contribute to these elevated levels are not established. We performed in vitro experiments to investigate the possibility that HIV-1 infection of mononuclear phagocytes directly induces enhanced neopterin production. We found that HIV-1-infected monocytes and peritoneal macrophages produced neopterin in quantities similar to amounts produced by uninfected cells. The HIV-infected cells responded to stimulation with IFN-gamma as well as uninfected cells, with a 6- to 12-fold increase in neopterin production. We conclude that elevated serum levels of neopterin in HIV-infected individuals are not caused by HIV-1 infection of mononuclear phagocytes but may be a result of the normal response to mononuclear phagocytes to increased levels of IFN-gamma.
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PMID:Neopterin production by HIV-1-infected mononuclear phagocytes. 796 72

We present and analyze a model for the cross-regulation of the Th1 and Th2 helper cell subsets during an immune response by the regulatory cytokines interferon-gamma (IFN)-gamma) and interleukin-10 (IL-10). IFN-gamma, secreted by Th1 cells, can inhibit the proliferation of Th2 cells. Interleukin-10, secreted by Th2 cells, inhibits cytokine production by Th1 cells. Based on these properties, the model shows that responses are expected to be dominated by either Th1 cells or Th2 cells but not both. Which type dominates is shown to depend principally on the relative efficiencies of activation of the responding Th1 and Th2 cells. However, our model, as well as numerous experiments, show that perturbations of the system allow one to switch from a Th2 to a Th1 response, or vice versa. Our model can account for observed outcomes of parasitic infection and may also contribute to our understanding of immune responses to HIV infection as well as to tolerance to self components. It also predicts that in certain parameter ranges vaccination with low doses of live parasites can provide protection against subsequent encounters with high doses that normally induce disease. Experiments by Bretscher et al. (1992, Science 257, 539) on Leishmania major infection are consistent with this prediction. A similar strategy may also be relevant for the design of an AIDS vaccine. Lastly, our results indicate that Th1/Th2 cross-regulation is capable of generating a "sneaking through" phenomenon, and hence it may play a role in tumor immunity.
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PMID:Th1/Th2 cross regulation. 796 33

In the 1980s, substantive experimental data and emerging clinical results suggested that interferon-gamma (IFN-gamma), a T-cell-derived lymphokine with broad macrophage-activating effects, had considerable potential in the treatment of nonviral infections as a host defense-enhancing antimicrobial agent. During the past 6 years, the breadth of the experimental activity with IFN-gamma against nonviral pathogens has been expanded still further, and pilot studies and formal clinical trials using IFN-gamma have been undertaken in the treatment of patients both at risk for and with active infections. Thus far, IFN-gamma has been approved for use as prophylaxis in patients with chronic granulomatous disease. However, IFN-gamma also appears effective as adjunctive therapy for at least one disseminated intracellular infection (visceral leishmaniasis), and in conjunction with conventional therapy, may benefit patients with certain forms of cutaneous leishmaniasis, disseminated Mycobacterium avium complex infection, and lepromatous leprosy. Despite a rationale for its use, IFN-gamma has not yet been tested in tuberculosis or fungal or common bacterial infections nor sufficiently examined in the prevention and/or treatment of the opportunistic infections related to acquired immunodeficiency syndrome. IFN-gamma remains a promising host defense-enhancing cytokine with still unexplored clinical potential.
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PMID:Interferon-gamma and host antimicrobial defense: current and future clinical applications. 797 35


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