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Biomedical subjects

D Jullien

Publications and source records attributed to D Jullien.

At least 19 recordsLinked to original sources
PubMed1999

CD1 expression by dendritic cells in human leprosy lesions: correlation with effective host immunity.

A potential role for the CD1 family of lipid Ag-presenting molecules in antimicrobial immunity in vivo was investigated in human leprosy skin lesions. Strong induction of three CD1 proteins (CD1a, -b, and -c) was observed in dermal granulomas in biopsy samples of involved skin from patients with the tuberculoid form of leprosy or with reversal reactions, which represent clinical patterns of disease associated with active cellular immunity to Mycobacterium leprae. In contrast, lesions from patients with the lepromatous form of the disease who lack effective cell-mediated immunity to the pathogen did not show induction of CD1 proteins. Thus, expression of CD1 correlated directly with effective immunity to M. leprae, as assessed by the clinical course of infection. CD1a, -b, and -c could be induced to similar levels on monocytes from the blood of either tuberculoid or lepromatous leprosy patients. This suggested that the absence of expression in lepromatous lesions was most likely due to local factors at the site of infection as opposed to a primary defect of the CD1 system itself. The majority of cells expressing CD1 in leprosy lesions were identified as a population of CD83+ dendritic cells. Initial in vitro studies of the Ag-presenting function of CD1+CD83+ monocyte-derived dendritic cells showed that such cells were highly efficient APCs for CD1-restricted T cells. These results indicate that the CD1 system can be up-regulated in human infectious diseases in vivo, and may play a role in augmenting host defense against microbial pathogens.

Antibodies, Monoclonal↗
PubMed1998

B7-1, but not CD28, is crucial for the maintenance of the CD4+ T cell responses in human leprosy.

We used human leprosy as a model to compare patterns of costimulatory molecule expression in respect to the clinical/immunologic spectrum of disease. We found that B7-1, B7-2, and CD28 transcripts dominated in tuberculoid leprosy patients, who have potent T cell responses to Mycobacterium leprae. In contrast, CTLA-4 was more strongly expressed in lesions from lepromatous patients, who manifest specific T cell anergy to the leprosy bacterium. T cell clones from tuberculoid lesions were CD4+CD28+ or CD4+CD28-, and T cell clones from lepromatous lesions were predominantly CD8+CD28-. The M. leprae-specific recall response of CD4+ T cell clones from tuberculoid lesions was blocked by anti-B7-1 mAb, but not by anti-B7-2 mAb or CTLA-Ig. However, anti-CD28 and anti-CTLA-4 mAbs did not block activation of clones from tuberculoid lesions, suggesting that B7-1 may utilize another costimulatory pathway. Peripheral blood T cell responses in the lepromatous form were strongly regulated by CD28 during T cell activation, in contrast to the tuberculoid form. Thus, B7-1 costimulation could play a role in maintaining a strong immune response to the pathogen.

Abatacept↗
PubMed1998

IL-15 enhances the response of human gamma delta T cells to nonpeptide [correction of nonpetide] microbial antigens.

Human gamma delta T cells have the ability to rapidly expand and produce IFN-gamma in response to nonpeptide Ags of microbial pathogens, in particular a class of compounds known as the prenyl phosphates. We investigated the ability of IL-15, a T cell growth factor, to modulate prenyl phosphate-induced gamma delta T cell proliferation and cytokine production. IL-15 significantly enhanced the expansion of gamma delta T cells in the peripheral blood after stimulation in vitro with isopentenyl pyrophosphate. Moreover, using gamma delta T cell clones, we determined that IL-15-induced T cell proliferation was dependent on the IL-2R beta chain but not the IL-2R alpha chain. We therefore studied the IL-15R alpha chain expression in human gamma delta T cells in the presence or absence of nonpeptide Ags. We found IL-15R alpha mRNA expression in IL-15-stimulated and Ag-stimulated human gamma delta T cells but not in resting gamma delta T cells. Although IL-15 itself had little effect on the production of IFN-gamma, IL-15 plus IL-12 acted synergistically to augment IFN-gamma production by gamma delta T cells. Moreover, we showed that this increase in IFN-gamma could be explained by the dual activation of STAT1 and STAT4 by IL-15 and IL-12, respectively. Taken together, these results suggest that IL-15 may contribute to activation of human gamma delta T cells in the immune response to microbial pathogens.

Antigens, Bacterial↗
PubMed1998

Three distinct sub-nuclear populations of HMG-I protein of different properties revealed by co-localization image analysis.

We have studied the nuclear distribution of the non-histone HMG-I protein by indirect immunofluorescence in several human and murine somatic cell lines and in growing mouse oocytes. We show that HMG-I, a high mobility-group protein which interacts in vitro with the minor groove of AT-rich B-DNA, is found exclusively in the nucleus and that this localization corresponds to a complex distribution. By comparing the HMG-I-dependent fluorescence signal with the chromatin density determined by Hoechst 33342 or propidium iodide staining, we present evidence for the existence of three HMG-I sub-populations whose contribution to the total fluorescence can be determined using a newly developed quantitative co-localization image analysis program: foci that correspond to regions of heterochromatin, intense dots located within decondensed chromatin, and a more diffuse component extending throughout the nucleoplasm. In addition, we show that these sub-populations differ in their sensitivity to nuclease digestion and in vivo displacement by the minor-groove binder Hoechst 33342. Finally, double immunolabeling of RNA polymerase II-dependent transcription and HMG-I shows that the intense dots are not correlated with sites of high transcriptional activity. We discuss the possibility that these three sub-populations reflect distinct and separable biological functions of the HMG-I protein.

3T3 Cells↗
PubMed1998

Coagulation factor XIII in scleroderma.

The ability of blood coagulation factor XIII (FXIII) to affect collagen synthesis and degradation led to its use in the treatment of scleroderma. Encouraging initial results were achieved principally in terms of skin sclerosis, musculoskeletal involvement and weakness. Further assessment of this treatment in scleroderma was abandoned when, following the HIV epidemic, FXIII use became strictly regulated. Safer concentrates are now available which may allow us to reconsider this therapy. This paper, which briefly reviews available data related to FXIII use in scleroderma and which proposes general rules for prescribing, is aimed at generating an open debate as to the need to widen the regulated use of FXIII to scleroderma.

Adult↗
PubMed1998

[Ofuji's papulo-erythroderma: treatment with cyclosporin A].

BACKGROUND: Papuloerythroderma of Ofuji is an uncommon condition characterized by diffuse pruriginous eruptions of infiltrating papulae. The large folds are not involved. The eruptions are associated with lymphopenia and eosinophilia. Very few cases have been reported in the literature and because of their heterogeneous nature, there is some debate as to whether this is a single clinical entity or a particular presentation of erythrodermia; Immunomodulation is recommended. CASE REPORT: A 73 year-old man of asian origin living in France presented chronic pruriginous erythrodermia with flat purplish-brown confluent papulae which did not involve the large folds. Eosophilia and lymphopenia were present. The biopsy specimen evidenced dermal infiltration with CD4+CD45+RO+ T cells, eosinophils and DC1a+ dendritic cells. Further explorations did not reveal any sign favoring lymphoma, carcinoma or underlying infection. Dermocorticoids, PUVA-therapy and interferon-alpha were ineffective. Considerable clinical improvement was obtained with cyclosporine A. DISCUSSION: We used ciclosporine A in our patient after repeated failure of other therapies reported to be effective in this dermatosis. Despite the favorable outcome, this therapeutic approach should be used with prudence.

Aged↗
PubMed1997

Mouse CD1 is mainly expressed on hemopoietic-derived cells.

The mouse CD1 (mCD1) is a class I-like molecule that is encoded outside the MHC. Recent studies demonstrate that mCD1 presents hydrophobic peptides to CD8+ T cells and also that it is recognized by a population of NK1.1+ T cells that are thought to play an immunoregulatory role because of their ability to secrete IL-4. It has previously been reported that mCD1 is expressed predominantly by intestinal epithelial cells, although most NK1.1+ T cells are located elsewhere. We, therefore, have generated new mAbs to mCD1 to investigate its tissue distribution. The principal site of mCD1 expression in normal mice is on cells in the hemopoietic series, including constitutive expression on nearly all T and B cells, on macrophages, and on dendritic cells. Other than bone marrow-derived cells, mCD1 is not widely expressed and is not detectable on great majority of intestinal epithelial cells. The B cells, but not the T cells, from beta2m-deficient mice can be recognized by two mCD1 autoreactive T hybridomas. Therefore, although we could not detect a beta2m-independent form of mCD1 using these mAbs, mCD1 in a different conformation or a mCD1-related molecule is likely to be expressed in the absence of beta2m on some cell types. The pattern of expression of mCD1 correlates with the distribution of NK1 T cells and is consistent with an important Ag-presenting function for this molecule.

Animals↗
PubMed1997

Interferon-gamma differentially regulates interleukin-12 and interleukin-10 production in leprosy.

The ability of monocytes to influence the nature of the T cell response to microbial pathogens is mediated in part by the release of cytokines. Of particular importance is the release of IL-12 and IL-10 by cells of the monocyte/macrophage lineage upon encountering the infectious agent. IL-12 promotes cell mediated immunity (CMI) to intracellular pathogens by augmenting T-helper type 1 responses, whereas IL-10 downregulates these responses. The ability of IFN-gamma to modulate the balance between IL-12 and IL-10 production was examined by studying leprosy as a model. In response to Mycobacterium leprae stimulation, IFN-gamma differentially regulated IL-12 and IL-10 production resulting in upregulation of IL-12 release and downregulation of IL-10 release. Furthermore, we determined that the mechanism by which IFN-gamma downregulates IL-10 was through the induction of IL-12. The data suggest a model of lymphocyte-monocyte interaction whereby the relative presence or absence of IFN-gamma in the local microenvironment is a key determinant of the type of monocyte cytokine response, and hence the degree of CMI in the host response to infection.

Down-Regulation↗
PubMed1997

IL-15, an immunomodulator of T cell responses in intracellular infection.

IL-15 is a novel cytokine with potent T cell growth factor activity. Here, we investigated the role of IL-15 in the human immune response to intracellular infection by studying patients leprosy. We found that IL-15 mRNA and protein were more strongly expressed in immunologically resistant tuberculoid patients than in with unresponsive and susceptible lepromatous patients. In vitro, Mycobacterium leprae induced IL-15 secretion from peripheral blood monocytes. Furthermore, rIL-15 by itself and in combination with rIL-2 or rIL-7 augmented PBMC proliferative responses to the pathogen. Although rIL-15 expanded the CD3-CD56+ (NK) subset, rIL-15 combined with M. leprae induced the expansion of CD3+CD56+ T cells. Immunohistologic analysis of leprosy skin lesions indicated that the frequency of CD56+ cells was greatest in the group of patients with high IL-15 expression, and that >90% of the CD56+ cells in lesions were CD3+ T cells. Therefore, IL-15 augments the local T cell response to human intracellular pathogen.

Cytoplasm↗
PubMed1997

cDNA sequence and expression pattern of the Drosophila melanogaster PAPS synthetase gene: a new salivary gland marker.

PAPS synthetase is a bifunctional enzyme containing both ATP sulfurylase and APS kinase activities required for the biosynthesis of PAPS, the sulfate donor in sulfation reactions. Here we report the sequence of the Drosophila melanogaster PAPS synthetase, the first gene implicated in the sulfation pathway to be described in that organism, and the characterization of its specificity of expression in embryos. Whole-mount in situ hybridization reveals that DmPAPSS is a novel salivary gland marker. At the end of embryogenesis, expression of DmPAPSS is also observed at the entry and exit of the gut and the posterior spiracles. We discuss the possibility that the pattern of expression of the DmPAPSS gene might reflect a major role for sulfation in mucus biosynthesis at the end of Drosophila embryogenesis.

Amino Acid Sequence↗
PubMed1996

Cross-regulatory roles of interleukin (IL)-12 and IL-10 in atherosclerosis.

T cell cytokines are known to play a major role in determining protection and pathology in infectious disease. It has recently become clear that IL-12 is a key inducer of the type 1 T cell cytokine pattern characterized by production of IFN-gamma. Conversely, IL-10 down-regulates IL-12 production and type 1 cytokine responses. We have investigated whether IL-12 and IL-10 might be involved in a chronic inflammatory reaction, atherosclerosis. In atherosclerotic plaques, we found strong expression of IFN-gamma but not IL-4 mRNAs as compared to normal arteries. IL-12 p40 mRNA and IL-12 p70 protein were also found to be abundant in atherosclerotic plaques. IL-12 was induced in monocytes in vitro in response to highly oxidized LDL but not minimally modified LDL. The cross-regulatory role of IL-10 was indicated by the expression of IL-10 in some atherosclerotic lesions, and the demonstration that exogenous rIL-10 inhibited LDL-induced IL-12 release. These data suggest that the balance between IL-12 and IL-10 production contributes to the level of immune-mediated tissue injury in atherosclerotsis.

Aorta↗
PubMed1996

Effect of IGF-I on phosphatidylinositol 3-kinase in soleus muscle of lean and insulin-resistant obese mice.

Insulin and IGF-I induced a similar stimulation of glucose transport in isolated soleus muscle. These actions require phosphatidylinositol (PI) 3-kinase activation since the PI 3-kinase inhibitor, wortmannin, blocked the stimulation by both peptides. We compared IGF-I with insulin in the ability to activate PI 3-kinase in the isolated soleus muscle from lean and gold thioglucose-induced obese insulin-resistant mice. In muscles from lean mice, IGF-I and insulin were able to activate PI 3-kinase with a similar time course, the effects being maximal within 3-5 min of stimulation. However, the IGF-I concentrations required to obtain similar effects on PI 3-kinase were about 10 times higher than the corresponding insulin doses. To determine through which receptor IGF-I was activating PI 3-kinase, the ability of IGF-I to activate both its own receptor and insulin receptor was simultaneously measured. Whatever the dose used (100 or 500 nmol/l), IGF-I activated to a nearly similar extent both the tyrosine kinase activity of its own receptor and that of the insulin receptor, suggesting that IGF-I was not only activating its receptor but was also able to stimulate the insulin receptor kinase. In muscles of obese insulin-resistant mice, although the defect of PI 3-kinase activation in response to IGF-I was relatively less pronounced (45%) than in response to insulin (70%) when compared with lean mice, PI 3-kinase stimulation was still markedly altered in response to IGF-I.

Androstadienes↗
PubMed1995

Overexpression of IL-10 in atopic dermatitis. Contrasting cytokine patterns with delayed-type hypersensitivity reactions.

The skin lesions of patients with atopic dermatitis provide a model to study immunoregulation in human allergy. To determine the local cytokine pattern of cells present (both endogenous and recruited) at the site of disease, we extracted RNA from skin biopsy specimens from patients with atopic dermatitis, allergic contract dermatitis, and positive tuberculin reactions and used PCR to assay for cytokine mRNA. cDNAs were normalized to the intensity of the CD3 delta PCR product as a marker of T cell mRNA. We found overexpression of IL-10 mRNA in atopic dermatitis lesions, in comparison with allergic contact dermatitis lesions and tuberculin reactions. In contrast, IL-4 mRNA was most strongly expressed in allergic contact dermatitis lesions and IFN-gamma mRNA was the predominant cytokine in tuberculin reactions. Using an anti-IL-10 mAb with immunoperoxidase, we localized IL-10 protein to large mononuclear cells in the dermal infiltrate of atopic lesions. After immunomagnetic sorting of mononuclear cell populations from PBMC of atopic dermatitis subjects, IL-10 mRNA as measured by PCR was found to be strongly expressed in CD14+ cells. Spontaneous release of IL-10 from PBMC-derived adherent cells was greater in atopic dermatitis donors than normal controls. We therefore renormalized skin biopsy cDNA according to the level of beta-actin PCR product, as a marker of total cellular mRNA, and found by PCR that IL-10 was nevertheless greatest in atopic dermatitis subjects. We conclude that the relative overexpression of IL-10 in atopic dermatitis greatest in atopic dermatitis subjects. We conclude that the relative overexpression of IL-10 in atopic dermatitis may contribute to the up-regulation of humoral responses and the down-regulation of Th1 responses.

Adult↗