Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UMLS:C0021051 (immunodeficiency)
71,517 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

CD8+ and CD8- subsets of peripheral blood natural killer (NK) cells were examined for susceptibility to infection with human immunodeficiency virus type 1 (HIV-1) and for the ability to produce various types of interferon (IFN) and tumor necrosis factor (TNF). HIV-1 was preferentially grown in CD8+ NK cells. The ability of CD8- NK cells to suppress HIV-1 replication was related to their ability to produce alpha IFN (IFN-alpha) upon viral induction. Induction with interleukin-2 resulted in IFN-gamma production in both subsets of NK cells. In the CD8+ subset, IFN-gamma and HIV-1 mutually enhanced the production of TNF alpha, leading to hyperactivation of viral replication, whereas in CD8- NK cells IFN-gamma primed HIV-induced IFN-alpha production. The dichotomous effects of IFN-gamma on HIV-1 replication were dependent on the IFN-alpha-producing ability of the cellular targets. These findings can explain the selective depletion of the CD16+ CD8+ subset that begins early in the in vivo HIV-1 infection.
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PMID:Differential replication of human immunodeficiency virus type 1 in CD8- and CD8+ subsets of natural killer cells: relationship to cytokine production pattern. 837 48

Most studies of apoptosis on T lymphocytes have examined the effects of various stimuli on immature T cells from the thymus. Previous work has indicated that apoptosis of mature memory T cells may be an important pathophysiologic mechanism in diseases such as AIDS, cancer, and autoimmunity. The effect of IL-2 on apoptosis of T cells is not clear. Therefore, we studied the ability of IL-2 to rescue Ag-specific T cells from apoptosis. We found that IL-2, in a dose-dependent manner, prevented T cells from entering apoptosis induced by gamma-irradiation, mitomycin C, or dexamethasone. This effect was specific for IL-2; IL-1 beta, IL-6, or IFN-gamma could not reproduce it. In contrast to Ag-specific T cells, immature T cells and naive mature peripheral T cells could not be rescued by IL-2 from radiation-induced apoptosis. Apoptosis rescue by IL-2 was associated with the induction of bcl-2 mRNA and protein. This induction could not be attributed to the effects of IL-2 on the cell cycle, as T cells that were prevented from cell cycle progression by irradiation showed a similar induction of bcl-2. Rescued cells retained their Ag-specific proliferative capacity and in vivo functions. These findings demonstrate that the apoptotic death of Ag-specific T cell lines, cells which can be regarded as a model for memory T cells, can be prevented with IL-2. This effect may have important therapeutic implications for patients receiving chemotherapy or radiotherapy, and for patients with AIDS who develop immunodeficiency primarily as a result of loss of Ag-specific memory T cells.
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PMID:IL-2 rescues antigen-specific T cells from radiation or dexamethasone-induced apoptosis. Correlation with induction of Bcl-2. 854 1

The Xid immunodeficiency was characterized by a total lack of B1 cells and reduced numbers and functions of B2 cells. In BALB.Xid mice, this defect results in an reduced susceptibility against infections with parasites such as Trypanosoma cruzi and Leishmania major. Since IL-7 acts on the B cell compartment by stimulation of pre-B cell proliferation, we analyzed the effect of recombinant IL-7 on L. major infection in BALB.Xid mice. After application of a single dose of IL-7 simultaneously with the infection, the clinical course in BALB.Xid mice was markedly aggravated, resembling that of normal BALB/c mice. IL-7-induced disease promotion was accompanied by an up to 100-fold higher parasite load in several tissues of these mice. When cytokine production of purified, L. major-specific CD4+ T cells from lesion-draining lymph nodes was examined, the IFN-gamma production seen in untreated BALB.Xid mice was suppressed in IL-7-treated animals. One of the major effects of IL-7 treatment in the lymphoid organs of BALB.Xid mice was the increase of the total number of B220, sIgM and MHC II-positive cells. These cells belonged to the B2 subset, since cells expressing surface molecules characteristic for B1 cells (Mac-1 and Ly-1) remained absent in spleens, lymph nodes and the peritoneum. In conclusion, selective up-regulation of B2 cells by IL-7 in the absence of B1 cells is associated with disease aggravation in L. major-infected BALB.Xid mice.
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PMID:Effect of IL-7 treatment on Leishmania major-infected BALB.Xid mice: enhanced lymphopoiesis with sustained lack of B1 cells and clinical aggravation of disease. 858 86

Comparison of immune responses to infection by a pathogenic or a nonpathogenic immunodeficiency virus in macaques may provide insights into pathogenetic events leading to simian AIDS. This work is aimed at exploring cytokine expression during infection by simian immunodeficiency virus (SIV). We used semiquantitative reverse transcription-PCR to monitor interleukin (IL)-2/interferon (IFN)-gamma (Th1-like), and IL-4/IL-10 (Th2-like) expression in unmanipulated peripheral blood mononuclear cells (PBMCs), during the acute phase of infection of eight cynomolgus macaques (Macaca fascicularis) with a pathogenic primary isolate of SIVmac251 (full-length nef), and of four other cynomolgus macaques by an attenuated molecular clone of SIVmac251 (nef-truncated). All the monkeys became infected, as clearly shown by the presence of infected PBMCs and by seroconversion. Nevertheless, PBMC-associated virus loads and p27 antigenemia in monkeys infected by the attenuated virus clone remained lower than those observed in animals infected with the pathogenic SIVmac251 isolate. A rise of IL-10 mRNA expression occurred in both groups of monkeys coincident with the peak of viral replication. In monkeys infected with the pathogenic SIVmac251, IL-2, IL-4, and IFN-gamma mRNAs were either weakly detectable or undetectable. On the contrary, animals infected by the attenuated virus exhibited an overexpression of these cytokine mRNAs during the first weeks after inoculation. The lack of expression of these cytokines in monkeys infected with the pathogenic primary isolate may reflect early immunodeficiency.
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PMID:Comparative interleukin (IL-2)/interferon IFN-gamma and IL-4/IL-10 responses during acute infection of macaques inoculated with attenuated nef-truncated or pathogenic SICmac251 virus. 862 92

In vitro interactions between interleukin (IL)-12, interferon (IFN)-gamma, and human immunodeficiency virus (HIV) type 1 infection in human macrophages were examined. Macrophages were infected with HIV-1 and cocultured with autologous monocyte-depleted peripheral blood mononuclear cells (PBMC). The addition of autologous PBMC to HIV-1-infected macrophages resulted in an expansive increase in reverse transcriptase (RT) activity; however, when both autologous PBMC and IL-12 were added, RT activity decreased (75%-90%) and high levels of IFN-gamma (9-16 ng/mL) were detected. The addition of anti-IFN-gamma antibodies blocked the IL-12-induced decrease in RT activity. Surprisingly, exogenous IL-12 added to HIV-infected macrophage cultures without autologous lymphocytes resulted in a 50%-60% reduction in RT activity and no detectable increase in IFN-gamma. The addition of anti-IFN-gamma did not inhibit this IL-12-mediated effect. These results suggest that IL-12 is capable of indirectly down-regulating HIV proliferation in macrophage cultures reconstituted with autologous PBMC and of directly suppressing HIV replication in purified macrophage cultures.
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PMID:Interleukin-12 decreases human immunodeficiency virus type 1 replication in human macrophage cultures reconstituted with autologous peripheral blood mononuclear cells. 862 17

Evidence is accumulating that T cells from human immunodeficiency virus type 1 (HIV-1)-infected individuals show accelerated cell death through apoptosis. We have recently demonstrated that the cross-linking of CD4 molecules (CD4XL) results in death of normal peripheral T cells through apoptosis and imbalanced cytokine secretion (ie, induction of tumor necrosis factor-alpha [TNF-alpha] and interferon-gamma [IFN-gamma] in the absence of interleukin-2 [IL-2] or IL-4 secretion). These upregulated cytokines (TNF-alpha/IFN-gamma) largely contributed to upregulation of the apoptosis-inducing cell surface molecule, Fas (APO-1/CD95) and apoptosis induction. The present study investigated the effect of vesnarinone as a novel immunomodulating agent on CD4XL-induced T-cell apoptosis. The addition of vesnarinone to peripheral blood mononuclear cells (PBMC) significantly inhibited CD4XL-induced lymphocyte apoptosis. This apoptosis-inhibitory effect of vesnarinone was associated with the blocking of CD4XL-induced TNF-alpha IFN-gamma secretion and of Fas antigen upregulation. However, vesnarinone did not block effects of exogenously supplemented TNF-alpha/IFN-gamma on Fas induction. These data suggest that vesnarinone inhibits CD4XL-induced TNF-alpha/IFN-gamma secretion, thereby blocking subsequent Fas upregulation and apoptosis induction. Given the potent pathogenic role of imbalanced cytokine secretion observed in HIV-infection, an agent such as vesnarinone may be of therapeutic value in slowing disease progression.
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PMID:Inhibition of CD4 cross-linking-induced lymphocytes apoptosis by vesnarinone as a novel immunomodulating agent: vesnarinone inhibits Fas expression and apoptosis by blocking cytokine secretion. 863 Mar 99

To characterize the mechanism by which interleukin 10 (IL-10) inhibits Th1 responses to intracellular pathogens, we evaluated the interaction between IL-10 and Mycobacterium tuberculosis-induced gamma interferon (IFN-gamma) production by peripheral blood mononuclear cells from persons across the spectrum of tuberculous infection. M. tuberculosis-induced IFN-gamma production was highest in healthy tuberculin reactors, intermediate in human immunodeficiency virus (HIV)-negative tuberculosis patients, and lowest in HIV-infected tuberculosis patients. Neutralizing antibodies to IL-10 increased IFN-gamma production in HIV-infected and HIV-negative tuberculosis patients by enhancing monocyte IL-12 production. Expression of the T-cell-costimulatory molecule CTLA-4 was depressed in M. tuberculosis-stimulated peripheral blood mononuclear cells from tuberculosis patients, and anti-IL-10 and Il-12 upregulated expression of CTLA-4. These findings provide evidence that intracellular pathogens can inhibit Th1 responses and downregulate expression of specific costimulatory molecules.
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PMID:Interleukin-10 downregulates Mycobacterium tuberculosis-induced Th1 responses and CTLA-4 expression. 864

We report the construction and characterization of several replication-competent simian immunodeficiency virus (SIV) vectors with a deletion in the viral nef gene (SIV(delta nef)) that express gamma interferon (IFN-gamma). The expression of the cytokine gene was controlled either by the simian virus 40 early promoter or by the SIV 5' long terminal repeat regulatory sequences, utilizing the nef gene splice signals. To enhance the expression of IFN-gamma, the two in-frame nef start codons were mutated without altering the Env amino acid sequence (SIV(HyIFN)). Plasmids containing full-length proviral genomes were used to obtain high-titer stocks of each recombinant virus in cell cultures. Expression of IFN-gamma by SIV(HyIFN) reached levels as high as 10(6) U/ml after 11 days in culture. The IFN-gamma gene was unstable and sustained deletions after serial passage of SIV(delta nef) vectors in CEM-X-174 cells. The degree of instability appears to depend on size and orientation of the insert and the expression of IFN-gamma. Only one virus, SIV(HyIFN), expressed detectable levels of IFN-gamma up to the sixth passage. Prospects for the use of IFN-gamma and other lymphokines to enhance the safety and efficacy of live attenuated vaccines are discussed.
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PMID:Construction and characterization of replication-competent simian immunodeficiency virus vectors that express gamma interferon. 864 49

One of the major obstacles to the development of successful recombinant vaccines against human immunodeficiency virus (HIV) and other intracellular pathogens is the identification of a safe and effective vaccine delivery system for the induction of cell mediated immunity with soluble protein antigens. In this study it was demonstrated that immunization with a recombinant HIV envelop (env) protein entrapped in biodegradable poly(lactide-co-glycolide) (PLG) microparticles induced consistent HIV-specific CD4+ and CD8+ T-cell responses in mice. Major histocompatibility complex (MHC) class I-restricted cytotoxic T lymphocytes (CTL) responses were detected following a single systemic immunization with gp120 entrapped microparticles and when given by the intranasal (i.n.) route induced HIV-specific CD8+ CTL and secretory IgA. Furthermore immunization with gp120 entrapped in microparticles generated CD4+ T cells that secreted moderate to high levels of IFN-gamma. Therefore, PLG microparticles are a safe and effective means of delivering antigen to the appropriate processing site for the generation of class I-restricted CTL, and are also capable of inducing Th1 cells.
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PMID:Immunization with a soluble recombinant HIV protein entrapped in biodegradable microparticles induces HIV-specific CD8+ cytotoxic T lymphocytes and CD4+ Th1 cells. 870 87

Since the human immunodeficiency virus (HIV-1) is transmitted either parenterally or sexually, both mucosal and systemic immune responses may be required to provide protective immunity. Attenuated Salmonella vectors expressing heterologous antigen can stimulate responses in both compartments. To evaluate the utility of Salmonella vectors as an HIV-1 vector vaccine, a gene expression cassette encoding recombinant HIV-1 gp120 (rgp120) was integrated into the hisOGD locus of Salmonella typhimurium aroA strain, SL3261 (SL3261::120). To test if increased antigen expression potentiates immunogenicity, strains were constructed that express rgp120 from a multicopy asd-stabilized plasmid (SL7207 pYA:120). Immunoblot analysis demonstrated that SL7207 pYA:120 expressed approximately 50-fold more rgp120 than SL3261::120. Oral immunization of BALB/c mice with these strains did not stimulate an env-specific CTL response or a significant rise in antigp120 antibody titer as compared to controls. However, splenic T cells from SL7207 pYA::120 immunized mice proliferated upon restimulation with gp120 in vitro while splenocytes from SL3261::120 immunized mice did not, gp120 restimulated splenic T cells from SL7207 pYA:120 immune mice also produced IFN-gamma but no IL-5. Two conclusions can be drawn from these results. First, high level expression of rgp120 in Salmonella vectors is necessary to stimulate a gp120-specific immune response in mice. Second, Salmonella::rgp120 stimulates a gp120-specific Th1 response in mice. This is the first report to describe the construction of a Salmonella::rgp120 vector vaccine that is immunogenic in mice.
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PMID:Construction and immunogenicity of Salmonella typhimurium vaccine vectors that express HIV-1 gp120. 871 22


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