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)

A case of chronic mucocutaneous candidiasis in a Malaysian child who subsequently developed disseminated tuberculosis and toxoplasmosis is described. The phenotype of her peripheral blood mononuclear cells showed discordance for her T cell markers. The presence of a subpopulation of CD2-/CD3+ mononuclear cells leading to an immunodeficiency state is consistent with failure of activation of CD2-mediated alternative pathway resulting in immunodeficiency. Such abnormal CD2-/CD3+ subpopulations have been described in lepromatous leprosy and foetal abortuses.
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PMID:Chronic mucocutaneous candidiasis with deficient CD2 (E receptor) but normal CD3 mononuclear cells. 168 66

The role of the interaction of CD2 molecules with lymphocyte function-associated antigen 3 (LFA-3) in facilitating nominal antigen recognition by T lymphocytes was studied by utilizing an HLA-DR4-restricted CD4+ cytotoxic human T-cell clone specific for human immunodeficiency virus envelope glycoprotein gp120 as a responder and murine fibroblasts transfected with human class II major histocompatibility complex (MHC) and/or human LFA-3 molecules as antigen-presenting cells (APC). Although expression of the DR4 restriction element in fibroblasts is sufficient for T-cell recognition of a gp120 peptide as judged by induction of proliferation coexpression of human LFA-3 on DR4+ APC decreases the molar requirement of nominal antigen by greater than one order of magnitude. Both LFA-3 and the relevant class II MHC molecules are necessary for antigen-independent conjugate formation, but the binding is further enhanced by specific nominal antigen. CD2-LFA-3 interaction is independent of T-cell receptor-MHC interaction and contributes directly to the stabilized conjugate between the T cell and LFA-3-bearing APC; soluble CD2 and monoclonal antibodies to LFA-3 and CD2 reduce T-cell-APC binding to the level mediated by nominal antigen and MHC. During conjugate formation, CD2 but not CD3 molecules are reorganized into the cell-cell interaction site in an antigen-independent manner. Thus, reorganization and/or coassociation of CD2 with CD3 molecules is not essential for T-cell activation.
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PMID:Role of interaction of CD2 molecules with lymphocyte function-associated antigen 3 in T-cell recognition of nominal antigen. 169 Aug 89

In addition to a well-documented depletion of CD4+ T helper cells in later stages of human immunodeficiency virus (HIV) infection, evidence has been provided for a specific unresponsiveness to triggering either by specific antigen in the context of autologous major histocompatibility molecules (self + X) or anti-CD3 monoclonal antibodies (MAb) in both CD4 and CD8 cells from asymptomatic HIV-infected individuals. In the present study we analyzed this unresponsiveness using mitogenic antibodies to distinct T cell membrane receptors. T cells from HIV-infected men who had normal numbers of CD4+ T cells responded poorly to activation signals via the CD3 membrane antigen in both accessory cell-dependent as well as accessory cell-independent culture systems. A similar low response was observed in an anti-CD2-driven system. In contrast, proliferation induced by anti-CD3, anti-CD2, or the phorbol ester Phorbol myristate acetate could be normally enhanced by anti-CD28 MAb. We demonstrated that this unresponsiveness is not due to a failure to induce early events required for activation, such as increased intracellular concentration of free calcium and activation of protein kinase C, but is caused by an imbalance between naive and memory T cells. In HIV-infected asymptomatic men, CD29+ memory T cells are selectively depleted which results in a poor responsiveness to self + X. These findings provide new insights that may have implications for our understanding of the immunopathogenesis of AIDS.
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PMID:Functional and phenotypic evidence for a selective loss of memory T cells in asymptomatic human immunodeficiency virus-infected men. 169 65

Melanins are pigments found in hair, skin, irides of the eye, and brain. Their functions in mammals include protection from exposure to sunlight, camouflage from predators, sexual recognition within species, and possible electron transfer reactants. Most natural melanins exist in an insoluble form, which is one reason there is little information on the biological properties of soluble melanins. Here, synthetic soluble melanins were obtained by chemical oxidation of L-tyrosine or spontaneous oxidation of L-beta-3,4-dihydroxyphenylalanine (L-dopa). Replication of human immunodeficiency virus types 1 and 2 (HIV-1 and HIV-2) was inhibited by soluble melanin in two human lymphoblastoid cell lines (MT-2 and H9) and in phytohemagglutinin-stimulated human T cells. Effective concentrations of 0.15-10 micrograms/ml had no cell toxicity. Melanin blocked infection by cell-free virus and interfered with HIV-induced syncytium formation and cytopathic effects when fusion-susceptible, uninfected cells, were mixed with chronically infected cells. Melanin also impeded the HIV-1 envelope surface glycoprotein, and T cell specific monoclonal antibody leu-3a (CD4), but not leu-5b (CD2), from binding to the surface of MT-2 cells. No effect on HIV-1 reverse transcriptase activity in viral lysates was observed. These results identify a unique biological property of melanin, and suggest that soluble melanins may represent a new class of pharmacologically active substances which should be further investigated for potential therapeutic utility in the treatment of Acquired Immune Deficiency Syndrome (AIDS).
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PMID:Selective antiviral activity of synthetic soluble L-tyrosine and L-dopa melanins against human immunodeficiency virus in vitro. 170 2

Heterotypic adhesion of T lymphocytes to monocytes, B lymphocytes, or other target cells is mainly mediated by LFA-1 and CD2 molecules. Low-affinity binding of resting T cells can be transiently up-regulated by cross-linking of CD3. We have previously found that binding of specific ligands to CD4 can down-regulate adhesion of resting T cells to B cells. We now show that the enhanced adhesiveness of CD4+ T cells induced by CD3 cross-linking using plastic-bound anti-CD3 antibody can also be inhibited by several CD4 ligands. i.e. anti-CD4 antibodies, the gp160 env protein of human immunodeficiency virus, as well as by putative CD4 ligands, i.e. synthetic peptides analogous to the gp160-binding site to CD4 (positions 418-434 and 449-464) and a 12-mer synthetic peptide (DR-12) analogous to positions 35-46 of HLA class II beta subunit and including the highly conserved Arg-Phe-Asp-Ser (RFDS) sequence. After CD3 cross-linking, maximal binding of T cells to HLA class II-positive and -negative B cells was similar, although binding to HLA class II-negative B cells was more prolonged. T cells that were passively induced to up-regulate adhesion by binding of a CD11a-specific antibody NKIL16, known to enhance LFA-1-dependent adhesiveness, were less sensitive to the inhibitory effect of the DR-12 peptide, whereas the inhibitory effects of gp160 were preserved. The kinetics of adhesion of NKIL16-pretreated T cells was not influenced by HLA class II expression at the B cell surface. Together, these results strongly suggest that CD4-HLA class II interaction may down-regulate low-affinity adhesion of resting T cells and, to some extent, high-affinity adhesion of T cells actively induced by CD3 cross-linking but not passively induced by an anti-CD11a antibody.
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PMID:Regulation of LFA-1-mediated T cell adhesion by CD4. 182 86

A synthetic peptide containing env amino acid (aa) sequence 581 to 597 of the transmembrane protein gp41 of human immunodeficiency virus type 1 (HIV-1) was tested for its effect on protein kinase C (PKC) and cytoplasmic free Ca2+ [( Ca2+]i) influx-dependent immune functions. We have previously shown that this peptide inhibits PKC-mediated phosphorylation and T-cell receptor-mediated [Ca2+]i influx as well as lymphoproliferation. In this study we demonstrate that the HIV-1 gp41 peptide aa581-597 inhibits lymphoproliferation stimulated via the distinct T-cell-activation molecules CD3, CD2, and CD28, as well as direct stimulation mediated by phorbol ester combined with ionomycin. Further, aa581-597 inhibits both PKC-dependent interleukin 2 (IL 2) production and the [Ca2+]i influx-dependent but PKC-independent induction of IL 2 receptor expression. The HIV-1 gp41 peptide also induces dramatic morphologic changes in lymphocytes, characterized by cytoplasmic ballooning and the acquisition of adherence to plastic, and these changes are dependent on both the length and the temperature of exposure. The results of this study suggest that the HIV-1 gp41 sequence aa581-597 acts at multiple sites to inhibit both PKC activity and [Ca2+]i influx, resulting in the abrogation of several distinct immune functions that are critical for an intact immune response and are defective in HIV-1-infected individuals.
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PMID:A synthetic peptide with sequence identity to the transmembrane protein GP41 of HIV-1 inhibits distinct lymphocyte activation pathways dependent on protein kinase C and intracellular calcium influx. 183 84

Primary membrane T cell immunodeficiencies (ID) have recently been characterized. In this paper we describe the main findings about the leukocyte adhesion deficiencies (LAD), the ID with low expression of the T cell receptor/CD3 complex, and the Omenn's syndrome. LAD is a consequence of mutations in the beta-chain-encoding gene of the leukocyte adhesion proteins. Functional consequences mainly affect phagocytic cells which are incapable of transendothelial migration. Effector T lymphocyte functions are, however, also impaired, i.e., helper T cell activity and cytotoxicity. The latter defect may account for the inability of LAD patients to reject HLA nonidentical bone marrow. Low expression of the T cell receptor CD3 complex is a rare entity characterized by a profoundly diminished expression of the whole complex on all T cells. The basic defect has not yet been unravelled. Interestingly, such T cells differentiate normally and can be activated by some antigens while anti-CD3 and anti-CD2 antibodies are not efficient. In five patients with Omenn's syndrome (combined immunodeficiency with eosinophilia), oligoclonal T cells were detected in blood, skin, and gut. These T cells are also in vivo activated. Since in one family, one sibling presented with typical SCID, i.e., alymphocytosis, and another with the Omenn's syndrome, it is proposed that the latter syndrome may correspond to a form of leakiness of SCID as found in the mice SCID model.
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PMID:Primary membrane T cell immunodeficiencies. 183 82

We have characterized CD4-CD8- double-negative (DN) alpha beta TCR+ T cells from a patient with immunodeficiency, lymphocytosis, lymphadenopathy, and hepatosplenomegaly. The majority of peripheral blood lymphocytes were DN alpha beta TCR+ T cells as evaluated by FACS and biochemical analysis. The DN T cells showed the following phenotype: alpha beta TCR+, gamma delta TCR-, CD2+, CD3+, CD4-, CD5+, CD7-, CD8-, CD16-, CD25-, CD26-, CD28+, CD45RO-, CD45RA+, CD57+, and HLA-DR+. Both southern blot analysis of TCR genes and FACS analysis applying a panel of V beta and V alpha monoclonal antibodies (MoAbs) indicated a polyclonal T-cell expansion. Thymic biopsy showed normal histology, whereas lymph node biopsy samples showed altered histological and immunohistological patterns with markedly expanded paracortical areas containing the DN T cells of the same phenotype as found in peripheral blood T cells. In functional studies, the DN T cells showed a profoundly reduced proliferative response upon stimulation with mitogens as well as MoAbs against the TCR/CD3 complex, CD2, and CD28, respectively. Addition of exogenous interleukin-2 (IL-2) only minimally augmented the proliferative response. In contrast, the addition of a combination of Ca2+ ionophore and phorbol 12-myristate 13-acetate (PMA) restored the proliferative response of the DN T cells to almost normal levels. This observation strongly suggests that the protein kinase C activity of the DN T cells was intact, but that the normal mechanism for transmembrane signal transduction was impaired in these unusual DN T cells.
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PMID:Phenotypical and functional characterization of double-negative (CD4-CD8-) alpha beta T-cell receptor positive cells from an immunodeficient patient. 183 26

The expression of human immunodeficiency virus type 1 (HIV) is enhanced after T cell activation due to the interaction of cell-encoded nuclear factors with binding sites in the viral long terminal repeats (LTR). We studied the minimal signal transduction requirements for induction of HIV transcription during T cell activation. Monoclonal antibodies (mAb) against the T cell receptor/CD3 complex induced interleukin (IL) 2 production as well as HIV-LTR-directed gene expression in Jurkat T cells. Addition of cyclosporin A or buffering of intracellular Ca2+ changes did not abolish this LTR-directed gene expression but did block IL 2 production. In contrast, interference with protein kinase C (PKC) activation did inhibit both IL 2 production and LTR-driven gene expression. Under all conditions HIV-LTR-directed gene expression correlated with gene expression induced by the NF-kB binding enhancer, but not by the NF-AT or OCT-1 binding sites. In accordance with observations by Verweij, Geerts and Aarden on the CD28 co-stimulatory activation of IL2 transcription via an NF-kB-like activity, stimulation of the CD2, CD28 and CD44 accessory molecules was tested to mimick physiological activation signals independent of T cell receptor triggering. mAb directed against CD2 and CD44 only marginally induced the LTR. Next, non-mitogenic stimulation by mAb against CD28 clearly induced the HIV-LTR- and NF-kB- but not NF-AT- and OCT-1-driven chloramphenicol acetyltransferase CAT expression, showing a direct effect on gene expression via this receptor. Taken together, this report shows that non-mitogenic T cell activation signals are sufficient to induce HIV transcription. The finding that these signals may be delivered by receptors that are not dependent on antigen-specific activation may have important implications for our understanding of HIV pathogenesis.
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PMID:Non-mitogenic T cell activation signals are sufficient for induction of human immunodeficiency virus transcription. 184 14

We investigated mechanisms by which the soluble native envelope glycoprotein gp120 of the human immunodeficiency virus (HIV-1) suppresses antigen-driven T cell responses. For this study, exogenous interleukin-2 (IL-2)-independent, antigen-specific, CD4 positive, human T-cell clones were developed by cyclic restimulation with soluble tetanus toxoid antigen. In the presence of soluble antigen and antigen-presenting cells (APC), T-cell clones proliferated and secreted IL-2. Purified gp120 suppressed the proliferative responses of the T-cell clones with concomitant suppression of IL-2 secretion; proliferative responses of CD8+ T cells preincubated with gp120 were not inhibited. A short pulse of 20 minutes with gp120 was sufficient to inhibit the proliferative response of the T-cell clones. Anti-CD3 monoclonal antibody (MoAb)-driven proliferation of the T-cell clones was also suppressed by gp120, but responses elicited by mitogens, phorbol myristate acetate (PMA) plus calcium ionophore, ionomycin, anti-CD2 MoAbs, and a combination of anti-CD3 plus anti-CD28 MoAb driven responses remained unaffected. Investigation of signal transduction events showed that antigen-driven early activation signals via translocation of protein kinase C (PKC), increase in intracellular inositol phosphates, and increase in intracellular calcium were suppressed in gp120 pretreated, tetanus toxoid antigen-stimulated T-cell clones. One mechanism of immune suppression by gp120 may involve interference with the initiation of signal transduction through the T-cell receptor complex.
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PMID:Inhibition of functional properties of tetanus antigen-specific T-cell clones by envelope glycoprotein GP120 of human immunodeficiency virus. 196 13


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