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)

We analyzed at clonal level the functional profile of circulating or skin-infiltrating T lymphocytes from two individuals infected with the human immunodeficiency virus type 1 (HIV-1), suffering from a Job's-like syndrome (eczematous dermatitis, recurrent skin and sinopulmonary infections, and hypergammaglobulinemia E) and showing virtually no circulating CD4+ T cells. Most of the CD3+ T cell clones generated from both patients were CD4- CD8+ TCR alpha beta +. The others were CD4- CD8- TCR alpha beta + which exhibited reduced mRNA expression for the CD8 molecule or no mRNA expression for either CD4 or CD8 molecules. The great majority of both CD4- CD8+ and CD4- CD8- did not produce interferon (IFN) gamma and exhibited reduced cytolytic activity. Rather, most of them produced large amounts of both interleukin (IL) 4 and IL-5 and provided B cell helper function for IgE synthesis. These data suggest that a switch of cytolytic CD8+ T cells showing a Th1-like cytokine secretion profile to cells that make Th2-type cytokines, exhibit reduced cytolytic potential, and provide B cell helper function can occur in the course of HIV-1 infection. These cells may contribute to the reduced defense against viral infections and intracellular parasites and account for the elevated IgE serum levels, eosinophilia, and the allergic-like clinical manifestations seen in a proportion of HIV-1-infected individuals.
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PMID:Th2-like CD8+ T cells showing B cell helper function and reduced cytolytic activity in human immunodeficiency virus type 1 infection. 804 28

We have previously reported a new spontaneous recessive mutation that induces a generalized lack of lymph nodes (LNs) and Peyer's patches (PPs) accompanied by immunodeficiency in mice (gene symbol, aly). In this study, we have analyzed gut-associated lymphatic tissues of the mutant aly/aly mice and have compared the intestinal intraepithelial T lymphocytes (IEL) in aly/aly and normal aly/+ littermate mice. Immunohistochemical studies revealed that colonization of IEL and lamina propria T cells takes place in the absence of PPs and IgA-producing B cells in the lamina propria. Absolute numbers of Thy-1- IEL-alpha beta and -gamma delta are not altered in aly/aly mutant mice, whereas absolute numbers of Thy-1+ IEL-alpha beta and -gamma delta in aly/aly mice are about half of those in aly/+ mice. In IEL-alpha beta from aly/aly mice, the major CD8 alpha alpha+ and CD8 alpha beta+ subsets are maintained, whereas CD4+ and CD4+, CD8+ subsets are reduced. Although the population size of major CD8 alpha alpha+ and CD4-, CD8- IEL-gamma delta subsets is slightly reduced, the use of TCR-gamma- and -delta-chain variable gene segments by IEL-gamma delta remains almost the same in aly/aly mice. The constitutive cytolytic activity of IEL-alpha beta and -gamma delta is attenuated sharply in the aly/aly condition. This activity is, however, augmented significantly after in vitro stimulation with anti-CD3 mAb. These results indicate that most of the IEL subpopulations develop independently of passage through PPs and mesenteric LNs and that the aly mutation interrupts cytotoxic IEL development during relatively late differentiation steps that convert cytotoxic precursors to the constitutively cytolytic state.
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PMID:Development of intestinal intraepithelial T lymphocytes is independent of Peyer's patches and lymph nodes in aly mutant mice. 805 6

New fluorescent monoclonal antibody-dye conjugates permit three-color immunofluorescence analysis of leukocytes in whole blood using a single laser flow cytometer. The fluorochrome used in this study is a tandem conjugate of phycoerythrin (PE) and Cyan-5, which is excitable at 488 nm with a maximum in the emission spectrum at > 650 nm and it can be used together with PE and fluorescein isothiocyanate (FITC). The directly labelled monoclonal antibodies are incubated with unseparated anticoagulated blood and subsequently erythrocytes are lysed by a standardized automated procedure. The resulting leukocyte suspension can then be analyzed for three different surface markers in an individual sample of 100 microliters blood. When compared simultaneously with single-color analysis triple-color immunofluorescence yielded identical quantitative and qualitative results on various lymphocyte subpopulations. The efficacy of this method was evaluated by analyzing leukocytes of 42 healthy donors for the following markers: CD3, CD4, CD8, CD14, CD16, CD19, CD25, CD38, CD45RO, CD45RA, CD56, CD57, TCR-gamma/delta and HLA-DR. Of special interest was the finding that CD45RA and CD45RO are differently expressed in CD4 and CD8 cells. The reliability and convenience of this three-color analysis will make it possible to do more sophisticated examinations of subpopulations and their relevance in the monitoring of autoimmune diseases, immunodeficiency syndromes including AIDS and malignant disorders such as leukemias.
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PMID:Triple immunofluorescence flow cytometry, using whole blood, of CD4+ and CD8+ lymphocytes expressing CD45RO and CD45RA. 810 28

Defective T cell activation has been recognized in a number of patients with primary immunodeficiencies (ID). A distal defect resulting in abnormal production of IL2, IL3, IL4 and IFN gamma was found to be associated with reduced binding of the NF-AT transcription factor to the promoters of the genes coding for these lymphokines. Defect in early steps of T cell activation have been described in primary IDs, consisting in defective calcium flux and phosphoinositides turnover following TCR/CD3 ligation. We herein report a primary ID found in a 13 year old girl. It consists in a partially defective T cell proliferation which could be related to a defective Tyrosine phosphorylation.
Immunodeficiency 1993
PMID:Functional T cell immunodeficiency characterized by defective TCR/CD3 induced tyrosylphosphorylation. 816 86

Defects in T cell function are known to be present in a subset of patients with CVID, but the true nature of these defects still has to be revealed. In prior studies we described that T cells from these patients show an impaired proliferative response following activation with recall antigens (E. coli, Tet. Tox., TBE and PPD). Gene expression of IL2 and IFN-gamma in patients' T cells following antigenic stimulation was significantly reduced compared to controls, while IL-2R transcripts were normal. To further characterize the defect we examined T cell responses to bacterial enterotoxins, collectively termed superantigens. Following stimulation with optimal (10 ng/ml p < 0.05) as well as suboptimal (1 ng/ml p < 0.0025) concentrations of staphylococcal enterotoxin A (SEA), proliferative response and cytokine release (IL-2 and IFNg) were significantly decreased in patients' T cells as compared to controls'. When patients' T cells were stimulated with staph. enterotox. C3 (SEC3) an even more pronounced difference between patients' and controls' T cells could be observed (10 ng/ml p < 0.002, 1 ng/ml p < 0.0005). Our data indicate that, in addition to the defect in antigen-induced T cell activation, T cells of CVID patients express a broader impairment in the interaction between the antigen presenting cell and the TCR.
Immunodeficiency 1993
PMID:Activation of CVID patients' T cells with conventional antigens and superantigens. 816 91

The analysis of the T cell repertoires involved in local or systemic immune responses is beginning to play an important role in many clinical situations. These include autoimmunity, response to viral or bacterial superantigens, alloimmunity including allograft rejection, and tumor immunity. Here we analyze circulating T cell repertoires by determining TCR beta-chain gene complexity using a modification of V beta family-specific PCR. This approach, called CDR3 size spectratyping, uses the size heterogeneity of the CDR3 as a further source of specificity in TCR analysis. It has been used here to analyze the complexity and stability of circulating T cell repertoires in normal adults, including bone marrow donors, and bone marrow transplant recipients. Normal spectratypes are both complex and stable. The repertoire complexity of marrow recipients correlates with their state of immune function. Contractions and gaps in repertoires are revealed in individuals suffering from recurrent infections associated with T cell impairment. Spectratype analysis is applicable to other studies of specific repertoire skewing such as may be associated with immunodeficiency or found at sites of immune activity.
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PMID:Circulating T cell repertoire complexity in normal individuals and bone marrow recipients analyzed by CDR3 size spectratyping. Correlation with immune status. 817 27

Immediately after infection of the targeted cell by HIV-1, proviral gene expression is limited to the three regulatory proteins, Tat, Rev, and Nef, with the nef transcript representing nearly 80% of total expression. Additionally, simian immunodeficiency virus Nef has been shown to be essential for high in vivo titer and the development of immunodeficiency. Recent findings demonstrate that the negative effects of Nef expression, as first defined in transformed T cell lines, are not present when Nef is expressed in primary human T cells or in T cells from transgenic mice, in which one sees moderate positive enhancements of HIV replication and the T cell activation process, respectively. We find that Nef expression in an Ag-specific murine T cell hybridoma results in both the down-modulation of CD4, as seen in primary cells and human T cell lines, and a positive enhancement of the TCR response to stimuli. Examination of a CD4- cell demonstrated that the positive enhancement is independent of CD4 expression or modulation. CD4 down-modulation is shown to be caused by a post-Golgi, acid-dependent process, which dramatically decreases the lifespan of the CD4 molecule. The TCR, Thy Ag, and CD45 remained unchanged in their surface expression. These findings suggest that Nef alters the normal routing and residencies of the CD4 molecule and that the positive effect of Nef on T cell activation is independent of this modulation.
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PMID:HIV-1 Nef activity in murine T cells. CD4 modulation and positive enhancement. 817 29

Human X-linked severe combined immunodeficiency disease (SCID) is an immunodeficiency disorder in which T cell development is arrested in the thymic cortex. B lymphocytes in children with X-linked SCID seem to differentiate normally. X-linked SCID is associated with a mutation in the gene that encodes the IL-2R gamma-chain. Because TCR-beta gene recombination is a pivotal initial event in T lymphocyte ontogeny within the thymus, we hypothesized that a failure to express normal IL-2R gamma could lead to impaired TCR-beta gene recombination in early thymic development. PCR was used to determine the status of TCR-beta gene-segment rearrangements in thymic DNA that had been obtained from children with X-linked SCID. The initial step in TCR-beta gene rearrangement, that of D beta to J beta recombination, was readily detected in all thymus samples from children with X-linked SCID; in contrast, V beta to DJ beta gene rearrangements were undetectable in the same samples. Both D beta to J beta and V beta to DJ beta TCR genes were rearranged in the thymic tissues obtained from immunologically normal children. We conclude that TCR beta-chain gene rearrangement is arrested in children with X-linked SCID. Our results suggest a causative relationship between the failure of TCR beta-chain gene rearrangements to proceed beyond DJ beta rearrangements and the production of a nonfunctional IL-2R gamma-chain.
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PMID:Arrested rearrangement of TCR V beta genes in thymocytes from children with X-linked severe combined immunodeficiency disease. 820 53

A wide spectrum of different immunologic abnormalities have been postulated as being responsible for the impairment of specific antibody production and the decrease in all or selected immunoglobulin isotypes present in common variable immunodeficiency (CVID). These abnormalities include impaired B cell differentiation and/or function, defective macrophage function, and significant T cell defects. The aim of the present study was to delineate whether the accessory molecule CD28 is involved in the impaired antigen response of T cells from patients with CVID. Our results demonstrate that CD28 costimulation was functional in T cells stimulated with anti-CD3 or anti-TCR MoAb, but could not correct the impaired response of patients' peripheral blood T cells to tetanus toxoid. Analysis of patients' long-term cultured T cells further confirmed these results. Exogenous rIL-2, another costimulus, augmented but did not correct the defective proliferation and lymphokine production in patients' antigen-driven peripheral blood T lymphocytes or in long-term cultured T cells. These findings indicate that the CD28 signalling pathway in these patients' T cells is unimpaired, and that costimulation via CD28 cannot correct the defect occurring in the course of TCR-mediated T cell activation.
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PMID:The costimulatory signal CD28 is fully functional but cannot correct the impaired antigen response in T cells of patients with common variable immunodeficiency. 830 93

Studies to assess the possibility that the HIV may encode a superantigen that plays a role in the depletion of functional CD4+ lymphocytes in the infected individual have yielded discrepant results. The problem in performing conclusive examinations of this issue may be attributed, at least in part, to the difficulty of prospectively studying individuals from before their infection until the time of profound CD4+ lymphocyte loss. To determine whether the AIDS virus deletes particular subpopulations of V beta-expressing lymphocytes, we have employed an animal model of AIDS, the simian immunodeficiency virus (SIV)-infected macaque monkey. Rhesus monkeys were experimentally infected with SIVmac and studied prospectively. A PCR-based quantitative method for assessing TCR repertoire was employed to analyze the expression of 24 V beta and 30 V alpha gene families in the monkeys. Although circulating PBL were increased in number by 3 wk after SIVmac infection, the expanded lymphocyte populations exhibited no significant perturbation in their TCR V beta repertoires. PBL obtained from monkeys before and 0.5 to 3 years after infection displayed no significant change in V beta and V alpha gene family expression. Finally, no deletion of V beta-expressing cell subpopulations could be demonstrated in purified CD4+ lymphocytes from infected monkeys. This was true even for monkeys whose blood contained less than 200 CD4+ lymphocytes/microliters. These results indicate that the TCR repertoire is conserved in SIVmac-infected rhesus monkeys and suggests that mechanisms other than superantigen-induced deletion must be responsible for CD4+ lymphocyte loss in these animals.
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PMID:Conserved T-cell receptor repertoire in simian immunodeficiency virus-infected rhesus monkeys. 839 99


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