Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0021051 (immunodeficiency)
 71,517 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chemokines play necessary and important roles in regulating the trafficking of lymphocytes to intra- or interlymphoid tissues as well as to sites of inflammation. The complex migratory patterns of lymphoid lineage cells is governed by subset-specific expression of chemokine receptors and their access to specific ligands. Several chemokine receptors and chemokine receptor-like orphan receptors also serve, in conjunction with CD4, as coreceptors for infection by human and simian immunodeficiency viruses (HIV and SIV). Here we show that the expression pattern of Bonzo/STRL33, an orphan SIV/HIV coreceptor, is highly restricted to the memory subset of T cells and is up-regulated upon stimulation of these cells with IL-2 or IL-15. Both the pattern and the regulation of Bonzo expression closely paralleled that of CC family chemokine receptors CCR5 or CCR6 and inversely correlated with CXCR4 expression. However, in striking contrast to CCR5, Bonzo expression was not down-modulated by PMA or mitogen stimulation of T cells. Targeted replacement of the Bonzo gene with a gene encoding green fluorescent protein in mice revealed that the expression and cytokine regulation of mouse Bonzo are comparable to those of its human counterpart. The similar expression and regulation patterns of Bonzo and the HIV coreceptor CCR5 may have implications for understanding the role of HIV/SIV receptors in viral evolution and pathogenesis.
 ...
PMID:The primate lentiviral receptor Bonzo/STRL33 is coordinately regulated with CCR5 and its expression pattern is conserved between human and mouse. 1097 45

In vivo, human immunodeficiency virus type 1 (HIV-1) is opsonized with complement fragments and virus-specific antibodies (Ab). Thus, HIV is able to interact with complement receptor (CR) - and Fc receptor (FcR) - positive cells such as B cells, follicular dendritic cells or macrophages. In this study we demonstrate that the interaction between B cells and HIV has an impact on autologous primary T cell infection in vitro. We confirmed the presence of complement-fragments and virus-specific Ab on serum-treated HIV using a virus-capture assay. In experiments with CR2-specific Ab we showed that the virus/B cell interaction was mainly dependent on CR2. In infection experiments immobilisation of HIV on stimulated tonsil B cells greatly enhanced the infection of interleukin (IL)-2-activated autologous tonsil T cells. Surprisingly, enhancement of T cell infection by B cell-HIV complexes was observed even in the absence of mitogenic stimuli such as PMA and was independent of the addition of exogenous IL-2. Taken together, these results indicate that primary B cells are able to efficiently transmit opsonised HIV to autologous primary T cells and induce a massive enhancement of infection. These in vitro experiments mimic the in vivo situation in the lymphoid tissue and suggest an alternative mechanism for the infection of primary T cells.
 ...
PMID:B cell-mediated infection of stimulated and unstimulated autologous T lymphocytes with HIV-1: role of complement. 1104 64

A variable degree of humoral immunodeficiency is a common feature in patients with B-cell chronic lymphocytic leukemia (B-CLL). The aim of this study was to explore the possibility that B-CLL cells play a direct role in this phenomenon. To this end, patients' bone marrow (BM) immunoglobulin (Ig)-secreting cells were cocultured with autologous purified B-CLL cells. The results show that tumoral cells inhibited the spontaneous IgG secretion by BM plasma cells, and this effect increased after PMA-induction of B-CLL cells. This inhibitory process was proportional to the number of B-CLL cells added and depended on cellular contact. Adhesion molecules did not appear to be involved in the cellular interaction, because the inclusion of blocking antibody to a variety of these proteins did not reverse the inhibitory phenomenon. However, the addition of monoclonal antibody that blocked the function of either CD95 or CD95L clearly reversed B-CLL cell inhibition on autologous BM plasma cells. These latter cells were shown to express CD95, and B-CLL cells contained detectable quantities of CD95L at the level of messenger RNA and protein. Annexin V-binding experiments revealed increased apoptosis of BM Ig-secreting cells when cocultured with autologous B-CLL cells. Finally, this inhibitory phenomenon might be operative in vivo because (a) there was a good correlation between the intensity of the inhibitory effect in vitro and the serum IgG level exhibited by every patient and (b) B-CLL cells also inhibited in vivo antigen-induced IgG-tetanus toxoid-secreting cells obtained from normal immunized subjects. Collectively, these data suggest that B-CLL cells inhibit autologous CD95-bearing Ig-secreting cells by the interaction with CD95L present on B-CLL cells and, hence, contribute to the state of humoral immunodeficiency that occurs in these patients.
 ...
PMID:Chronic lymphocytic leukemia B cells inhibit spontaneous Ig production by autologous bone marrow cells: role of CD95-CD95L interaction. 1104 99

The SF1 element (nucleotide -135 to -131) in the U3 region of the simian immunodeficiency virus (SIV) 5' to the NF-kappaB binding site plays a role in basal expression of SIV [Winandy et al., J Virol 66:5216-5223, 1992]. Using the electrophoretic mobility shift assay, we have characterized a specific SF1 binding factor (sf1) in the nuclear fractions of transformed T cells as well as monocytic and macrophage leukemic cells. A strong SF1 binding activity was demonstrated in all cell types. The SF1 binding activity was unaffected by treatment with PMA, PHA, or Ca(2+) ionophore. The HIV-1 long terminal repeat (LTR) 5' to the NF-kappaB site contained a homologous element which showed a specific binding complex of different mobility. The sf1 interacting with SIV LTR was composed of multiple proteins judged from UV crosslinking, some of which might be related to Jun/Fos proteins. Copyright 1996 S. Karger AG, Basel
 ...
PMID:AP1-Related Factors Interact with Simian Immunodeficiency Virus Long Terminal Repeats. 1172 97

Hyper IgE syndrome (HIES) is a rare immunodeficiency disorder characterized mainly by high levels of polyclonal IgE in serum and recurrent staphylococcal abscesses of the skin and lungs. The raised IgE levels have led researchers to study the synthesis of cytokines that regulate switching of immunoglobulin production towards IgE such as interleukin-4 (IL-4), IL-12 and interferon-gamma (IFN)-gamma. However, the role of IL-13 in the disease pathogenesis has not been investigated extensively. In this study, we investigated intracellular expression of IL-4 and IL-13 in mononuclear cells and CD4+ cells isolated from patients with HIES and healthy controls. Cells were stained intracellularly with antibodies directed against IL-4 and IL-13 and analysed by flow cytometry before and after activation with PMA and calcium ionophore. The mean proportion of resting or activated IL-4 and IL-13 expressing mononuclear cells were comparable in the two groups as well as the proportion of IL-4 expressing CD4+ cells. In contrast, the mean proportion of IL-13 expressing CD4+ cells was increased significantly in patients with HIES in both the resting and the activated state compared to healthy controls. We conclude that increased expression of IL-13 in CD4+ cells from patients with HIES could account, at least partly, for raised IgE levels in those individuals.
 ...
PMID:Increased expression of interleukin-13 but not interleukin-4 in CD4+ cells from patients with the hyper-IgE syndrome. 1206 9

The viral replication rate in patients infected with human immunodeficiency virus type 1 (HIV-1) is controlled in part by regulation of the transcription of viral genes. The rate of transcription is determined by a complex interplay between cellular and viral proteins and the promoter elements found in the long terminal repeats. Protein phosphatase 2A (PP2A) is a phosphoprotein that plays important roles in the regulation of signal transduction and cell growth. In this report, we demonstrate that overexpression of the catalytic subunit of protein phosphatase 2A (PP2Ac) increases the basal activity of the HIV-1 promoter and, especially, enhances the promoter's response to the protein kinase C (PKC) activator 12-O-tetradecanoyl phorbol-13-acetate (PMA). Additionally, ectopic PP2Ac enhances activation of HIV-1 provirus by PMA. Okadaic acid, a potent inhibitor of PP2A, markedly reduces both HIV-1 enhancer and proviral activation. Fostriecin, a PP2A inhibitor which has been used as an antineoplastic agent in clinical trials, is also able to inhibit PMA-stimulated HIV-1 proviral activation. These observations demonstrate a role for the important cellular phosphatase PP2A in HIV-1 transcription and replication and also suggest that PKC can potentiate the activity of PP2A. PP2A is a potential target for therapeutic intervention in patients infected with HIV-1.
 ...
PMID:Protein phosphatase 2A enhances activation of human immunodeficiency virus type 1 by phorbol myristate acetate. 1252 65

Ultraviolet (UV) radiation is a potent activator of the human immunodeficiency virus (HIV) gene expression in a HeLa cell clone with stably integrated copies of the HIVcat reporter construct. Recently, we have shown that activation of p38 MAP kinase and NF-kappaB is necessary but not sufficient for triggering efficient HIV gene expression in response to UV. Here we demonstrate that St. John's wort is a potent inhibitor of the UV-induced activation of HIV gene expression in HeLa cells. Stably transfected HIVcat/HeLa cells were preincubated with different amounts (25-100 microl) of St. John's wort or gingko biloba extracts for 30 min, then irradiated with UV (30 J/m2). In contrast to ginkgo biloba, St. John's wort inhibited the UV-induced HIV gene expression in a dose-dependent manner. Furthermore, preincubation with St. John's wort (10, 20, and 30 microl) for 30 min before UV (30 J/m2) irradiation, PMA- and UV-induced NF-kappaB activation was completely blocked, whereas ginkgo biloba did not affect the PMA- and UV-induced NF-kappaB activation in HeLa cells. UV activation of p38 MAP kinase was not inhibited by St. John's wort or by ginkgo biloba. However, we found that p38 MAP kinase and JNK1 and -2 were activated by St. John's wort, but p44/42 MAP kinase was not activated by St. John's wort in HeLa cells. Hypericin an active ingredient in St. John's wort also inhibited the UV activation of HIV gene expression in HeLa cells. These results firmly confirm that St. John's wort is a potent inhibitor of the UV-induced activation of HIV gene expression in HeLa cells.
 ...
PMID:Mood-enhancing antidepressant St. John's wort inhibits the activation of human immunodeficiency virus gene expression by ultraviolet light. 1266 47

Like other HIV-1 (human immunodeficiency virus type 1) proteins, Tat undergoes rapid mutation and occurs in numerous sequence variants in nature. Virus isolated from patients often has defects in Tat that lower its activity. The levels of P-TEFb, an essential cellular cofactor for Tat, are elevated by T-cell activation. To test the hypothesis that stimulation of P-TEFb levels might compensate for attenuation of Tat activity, we generated Tat constructs with a range of transactivation function. Transactivation by the Tat mutants correlated with their ability to bind to P-TEFb in vitro. Treatment of U937 cells with the phorbol ester PMA (phorbol myristate acetate) induced P-TEFb and stimulated Tat transactivation for alleles with basal transcription activity above a threshold (>5% compared to wild-type). Highly active alleles (>66% of wild-type) were stimulated to a lesser extent than those with activity in the intermediate range. Thus, attenuation of Tat function, in concert with low levels of P-TEFb activity, could serve to keep the virus in a latent state in quiescent cells yet permit viral replication after cell activation.
 ...
PMID:Differential activation of Tat variants in mitogen-stimulated cells: implications for HIV-1 postintegration latency. 1278 38

Selective IgA deficiency is the most common form of primary immunodeficiency, the molecular basis of which is unknown. To investigate the cause of selective IgA deficiency, we examined what stage of B-cell differentiation was blocked. DNA and RNA were extracted from three Japanese patients with selective IgA deficiency and three with a partial IgA deficiency. In selective IgA deficiency patients, Ialpha germline transcript expression levels decreased and alpha circle transcripts were not detected. Stimulation with PMA and TGF-beta1 up-regulated Ialpha germline and alpha circle transcripts. In some patients, IgA secretion was induced by stimulation with anti-CD40, IL-4 and IL-10. In partial IgA deficiency patients, Ialpha germline, alpha circle transcripts and Calpha mature transcripts were detected in the absence of stimulation. Our findings suggest that the decreased expression level of Ialpha germline transcripts before a class switch might be critical for the pathogenesis of some patients with selective IgA deficiency. However, in patients with a partial IgA deficiency, B-cell differentiation might be disturbed after a class switch.
 ...
PMID:Molecular analysis of B-cell differentiation in selective or partial IgA deficiency. 1508 92

In this report we evaluated CD4(+) T, CD8(+) T and natural killer (NK) cell counts, the levels of naive/memory subsets within the CD4(+) T lymphocyte population, expression of CD38 on T lymphocytes, and CD4(+) and CD8(+) T cell cytokine production in two girls with hyper-IgM (HIM) syndrome. Both girls developed recurrent infections early in infancy, presenting a wide spectrum of clinical manifestations, with a strikingly different disease severity between them. CD4(+) T cell counts were low in both children (patient 1: 214 cells/mm(3) and patient 2: 392 cells/mm(3)), and the CD4/CD8 T cell ratio was 0.4 for patient 1, the patient with the more severe disease, and 1.4 for patient 2. NK cell numbers were low in patient 1 (60 cells/mm(3)) and borderline (286 cells/mm(3)) with regard to normal levels in patient 2. An imbalance of naive and memory/effector cell subsets was found in both girls, with the percentage of CD45RA(+) 27(+) (naive) CD4(+) T lymphocytes being 5.8 and 12.4 for patients 1 and 2, respectively. Expression of CD38 on the surface of T lymphocytes was low in patient 1. Detection of intracellular interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha in CD4(+) and CD8(+) T lymphocytes upon PMA-Io stimulus was preserved in both children. In conclusion, we found low numbers of CD4(+) T lymphocytes and a dramatic redistribution of naive and memory/effector CD4(+) T lymphocytes in two girls with non-X-linked HIM syndrome. Furthermore, we found low expression of CD38 on T lymphocytes and low numbers of NK cells in the patient with the more severe disease, indicating a possible role for these cells in the pathogenesis of this immunodeficiency.
 ...
PMID:An imbalance of naive and memory/effector subsets and altered expression of CD38 on T lymphocytes in two girls with hyper-IgM syndrome. 1508 93


<< Previous 1 2 3 4 5 6 7 8 Next >>