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El Azami El Idrissi M, Ladant D, Leclerc C. The adenylate cyclase of Bordetella pertussis: a vector to target antigen presenting cells. Toxicon 2002; 40:1661-5. [PMID: 12457876 DOI: 10.1016/s0041-0101(02)00205-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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52
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Leclerc C, Perhirin M, Bossard AE, Lebrun C. [Laryngeal mask for adenoidectomy: some useful cautions]. ANNALES FRANCAISES D'ANESTHESIE ET DE REANIMATION 2002; 21:451. [PMID: 12078446 DOI: 10.1016/s0750-7658(02)00631-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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53
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Leclerc C, Perhirin M, De Rugy MG, Valdazo A. [Severe laryngeal injury due to a nasogastric tube]. ANNALES FRANCAISES D'ANESTHESIE ET DE REANIMATION 2002; 21:306-9. [PMID: 12033100 DOI: 10.1016/s0750-7658(02)00608-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
We report the case of a 71-year-old woman where nasogastric tube provoked a severe laryngeal injury, revealed by acute respiratory distress. Direct laryngoscopic findings included arytenoid edema, postcricoid ulceration and bilateral vocal cord paralysis in adduction. A tracheotomy was performed. Several months later, no improvement was noted because of a cricoid necrosis. Physiopathology, prophylaxis and management are discussed.
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54
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Nicolas MT, Leclerc C, Moreau M. [Calcium and bioluminescent probes]. JOURNAL DE LA SOCIETE DE BIOLOGIE 2002; 195:261-9. [PMID: 11833463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Ca2+ is an universal second messenger in numerous cell physiological processes. Aequorin, a bioluminescent calcium-binding protein is used today as a cellular probe to measure and image variations in calcium concentrations. The paper describes the characteristics and the use of aequorin as a luminescent calcium probe, and the future in the use of this protein for calcium imaging.
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55
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Savignac M, Moreau M, Leclerc C, Paulet P, Druet P, Pelletier L. [Calcium-dependent pathways involved in the production of cytokines in lymphocytes]. JOURNAL DE LA SOCIETE DE BIOLOGIE 2002; 195:309-17. [PMID: 11833469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
CD4+ T lymphocytes are divided in Th1 cells producing IFN gamma and Th2 cells that synthetize IL-4. This paper describes signaling pathways activated following T cell receptor (TCR) engagement and emphasizes differences that can account for differential cytokine production. This paper focuses on a new signaling pathway involved in IL-4 synthesis. This pathway couples the TCR to PKC that controls a calcium entry through dihydropyridine sensitive calcium channels. The calcium response is sufficient to initiate IL-4 gene transcription. Differing from that of IL-4, IFN gamma gene expression always requires MAP-kinase activation in addition to a calcium signal.
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56
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Leclerc C, Rizzo C, Daguzan C, Néant I, Batut J, Augé B, Moreau M. [Neural determination in Xenopus laevis embryos: control of early neural gene expression by calcium]. JOURNAL DE LA SOCIETE DE BIOLOGIE 2002; 195:327-37. [PMID: 11833471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
In amphibian embryos the central nervous system derives from the dorsal region of the ectoderm. Molecular studies led to the formulation of the "neural default model" in which neural development is under the inhibitory control of members of the BMP family. These growth factors also act as epidermis inducers. The neural fate is revealed by factors secreted by the Spemann Organizer such as noggin, chordin, follistatin, Xnr3 and cerberus which act by blocking BMP signalling. We propose a new model for neural cell determination in which a signalling pathway controlled by an increase in intracellular calcium suppresses the epidermis fate and activates the neural fate instead. This increase in calcium is due to an influx through calcium channels of the L-type, expressed in ectodermal cells during gastrulation. The possible involvement of a calcium-dependent phosphatase (calcineurin) to inhibit the epidermis fate and a calcium-calmodulin kinase (CaMkinase II) which activates the neural fate is discussed.
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Schlecht G, Leclerc C, Dadaglio G. Induction of CTL and nonpolarized Th cell responses by CD8alpha(+) and CD8alpha(-) dendritic cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 167:4215-21. [PMID: 11591742 DOI: 10.4049/jimmunol.167.8.4215] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Two distinct dendritic cell (DC) subpopulations have been evidenced in mice on the basis of their differential CD8alpha expression and their localization in lymphoid organs. Several reports suggest that CD8alpha(+) and CD8alpha(-) DC subsets could be functionally different. In this study, using a panel of MHC class I- and/or class II-restricted peptides, we analyzed CD4(+) and CD8(+) T cell responses obtained after i.v. injection of freshly purified peptide-pulsed DC subsets. First, we showed that both DC subsets efficiently induce specific CTL responses and Th1 cytokine production in the absence of CD4(+) T cell priming. Second, we showed that in vivo activation of CD4(+) T cells by CD8alpha(+) or CD8alpha(-) DC, injected i.v., leads to a nonpolarized Th response with production of both Th1 and Th2 cytokines. The CD8alpha(-) subset induced a higher production of Th2 cytokines such as IL-4 and IL-10 than the CD8alpha(+) subset. However, IL-5 was produced by CD4(+) T cells activated by both DC subsets. When both CD4(+) and CD8(+) T cells were primed by DC injected i.v., a similar pattern of cytokines was observed, but, under these conditions, Th1 cytokines were mainly produced by CD8(+) T cells, while Th2 cytokines were produced by CD4(+) T cells. Thus, this study clearly shows that CD4(+) T cell responses do not influence the development of specific CD8(+) T cell cytotoxic responses induced either by CD8alpha(+) or CD8alpha(-) DC subsets.
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58
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Fayad KP, Simao-Beaunoir AM, Gauthier A, Leclerc C, Mamady H, Beaulieu C, Brzezinski R. Purification and properties of a beta-1,6-glucanase from Streptomyces sp. EF-14, an actinomycete antagonistic to Phytophthora spp. Appl Microbiol Biotechnol 2001; 57:117-23. [PMID: 11693907 DOI: 10.1007/s002530100780] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Extracellular enzymes with glucanase activities are an important component of actinomycete-fungus antagonism. Streptomyces sp. EF-14 has been previously identified as one of the most potent antagonists of Phytophthora spp. A beta-1,6-glucanase (EC 3.2.1.75; glucan endo-1,6-beta-glucosidase) was purified by four chromatographic steps from the culture supernatant of strain EF-14 grown on a medium with lyophilized cells of Candida utilis as main nutrient source. The glucanase level in this medium followed a characteristic pattern in which the rise of beta-1,6-glucanase activity always preceded that of beta-1,3-glucanase. The molecular mass of the enzyme was estimated to be 65 kDa and the pI approximately 5.5. It hydrolyzed pustulan by an endo-mechanism generating gentiobiose and glucose as final products. Laminarin was not hydrolyzed indicating that the enzyme does not recognize beta-1,6-links flanked by beta-1,3-links. No significant clearing of yeast cell walls in liquid suspensions or in agar plates was observed indicating that this beta-1,6-glucanase is a non-lytic enzyme. This is the first beta-1,6-glucanase characterized from an actinomycete.
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59
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Badou A, Savignac M, Moreau M, Leclerc C, Foucras G, Cassar G, Paulet P, Lagrange D, Druet P, Guéry JC, Pelletier L. Weak TCR stimulation induces a calcium signal that triggers IL-4 synthesis, stronger TCR stimulation induces MAP kinases that control IFN-gamma production. Eur J Immunol 2001; 31:2487-96. [PMID: 11500833 DOI: 10.1002/1521-4141(200108)31:8<2487::aid-immu2487>3.0.co;2-l] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Th1 and Th2 cells produce different cytokines and have distinct functions. Th1/Th2 cell differentiation is influenced, among other factors, by the nature of TCR-MHC interactions. However, how the TCR transduces a signal resulting in IFN-gamma or IL-4 production is a matter of debate. For example, some authors reported a loss of calcium signaling pathway in Th2 cells. We used a T cell hybridoma producing IL-4 upon weak TCR stimulation and both IL-4 and IFN-gamma for strong TCR engagement as a model to study how TCR signaling pathways are differentially activated in both conditions of stimulation and how this influences the production of cytokines. We show that: (1) the calcium response is identical following weak and strong TCR stimulation; (2) mitogen-activated protein kinase(MAPK) activation is a gradual phenomenon depending upon the strength of TCR activation; (3) a calcium response, even weak, triggers IL-4 expression; (4) IFN-gamma synthesis requires not only a calcium response but also MAPK activation. The MAPK pathway is dispensable for IL-4 production, although it amplifies IL-4 synthesis upon strong TCR stimulation; (5) TCR-induced IL-4 production also depends on calcium signaling in Th2 cells, while IFN-gamma synthesis is dependent, in addition, on MAPK activation in Th1 cells.
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60
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Fayolle C, Osickova A, Osicka R, Henry T, Rojas MJ, Saron MF, Sebo P, Leclerc C. Delivery of multiple epitopes by recombinant detoxified adenylate cyclase of Bordetella pertussis induces protective antiviral immunity. J Virol 2001; 75:7330-8. [PMID: 11462005 PMCID: PMC114968 DOI: 10.1128/jvi.75.16.7330-7338.2001] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
CyaA, the adenylate cyclase toxin from Bordetella pertussis, can deliver its N-terminal catalytic domain into the cytosol of a large number of eukaryotic cells and particularly into professional antigen-presenting cells. We have previously identified within the primary structure of CyaA several permissive sites at which insertion of peptides does not alter the ability of the toxin to enter cells. This property has been exploited to design recombinant CyaA toxoids capable of delivering major histocompatibility complex (MHC) class I-restricted CD8(+) T-cell epitopes into antigen-presenting cells and to induce specific CD8(+) cytotoxic T-lymphocyte (CTL) responses in vivo. Here we have explored the capacity of the CyaA vector carrying several different CD8(+) T-cell epitopes to prime multiple CTL responses. The model vaccine consisted of a polyepitope made of three CTL epitopes from lymphocytic choriomeningitis virus (LCMV), the V3 region of human immunodeficiency virus gp120, and chicken ovalbumin, inserted at three different sites of the catalytic domain of genetically detoxified CyaA. Each of these epitopes was processed on delivery by CyaA and presented in vitro to specific T-cell hybridomas. Immunization of mice by CyaA toxoids carrying the polyepitope lead to the induction of specific CTL responses for each of the three epitopes, as well as to protection against a lethal viral challenge. Moreover, mice primed against the vector by mock CyaA or a recombinant toxoid were still able to develop strong CTL responses after subsequent immunization with a recombinant CyaA carrying a foreign CD8(+) CTL epitope. These results highlight the potency of the adenylate cyclase vector for induction of protective CTL responses with multiple specificity and/or broad MHC restriction.
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61
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Leclerc C, Gérard JL, Bricard H. [Intraoperative memory. A study of its incidence in general anesthesia in 326 patients]. ANNALES FRANCAISES D'ANESTHESIE ET DE REANIMATION 2001; 20:592-9. [PMID: 11530746 DOI: 10.1016/s0750-7658(01)00446-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVES Measuring the incidence of intraoperative recall in our hospital. STUDY DESIGN Prospective study. PATIENTS AND METHODS Three hundred and twenty-six patients who underwent a general anaesthesia for elective surgery on selected sites (general, urology, ORL, gynaecology and obstetrical, vascular and cardiac, thoracic) were interviewed on the first or the second postoperative day using a standard questionnaire. When recall was suspected, the anaesthetist was consulted and the anaesthetic record was looked at in order to evaluate the authenticity of any recollections. RESULTS Four patients mentioned an anomaly evoking intra-operative recall. The reduction in the anaesthetic level would explain authentic recollection for one patient. The recollection of another patient could not be truly verified. The site was the same for these two cases and the anaesthetic protocol for digestive surgery comprised curare and droperidol. The recollections for the two other patients did not correspond to the intraoperative period. The incidence of this phenomenon on the totality of sites was 0.6 per cent. CONCLUSION This result conforms to other studies. This phenomenon is a quality indicator, but probably under estimated. Although retrospective, this evaluation is quick and easy. This research in post-operative period should be systematic in order to find the reason and to propose an early course of action for these patients. An analysis of the anaesthetic protocol is necessary when the frequency of intraoperative recall is too high.
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Savignac M, Badou A, Moreau M, Leclerc C, Guéry JC, Paulet P, Druet P, Ragab-Thomas J, Pelletier L. Protein kinase C-mediated calcium entry dependent upon dihydropyridine sensitive channels: a T cell receptor-coupled signaling pathway involved in IL-4 synthesis. FASEB J 2001; 15:1577-9. [PMID: 11427491 DOI: 10.1096/fj.00-0733fje] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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63
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Leclerc C. [Is ketamine useful for anesthesia in morbid obesity?]. ANNALES FRANCAISES D'ANESTHESIE ET DE REANIMATION 2001; 20:422-3. [PMID: 11392258 DOI: 10.1016/s0750-7658(01)00391-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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64
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Webb SE, Moreau M, Leclerc C, Miller AL. Calcium in development: from ion transients to gene expression. Bioessays 2001; 23:372-4. [PMID: 11268044 DOI: 10.1002/bies.1053] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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65
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Guermonprez P, Fayolle C, Karimova G, Ullmann A, Leclerc C, Ladant D. Bordetella pertussis adenylate cyclase toxin: a vehicle to deliver CD8-positive T-cell epitopes into antigen-presenting cells. Methods Enzymol 2001; 326:527-42. [PMID: 11036662 DOI: 10.1016/s0076-6879(00)26074-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
MESH Headings
- Adenylate Cyclase Toxin
- Adenylyl Cyclases/metabolism
- Amino Acid Sequence
- Animals
- Antigen-Presenting Cells/immunology
- Artificial Gene Fusion
- Bacterial Proteins/genetics
- Bacterial Proteins/isolation & purification
- Base Sequence
- Bordetella pertussis/genetics
- CD8-Positive T-Lymphocytes/immunology
- Chickens
- Cytotoxicity, Immunologic
- Epitopes/genetics
- Female
- Genes, Reporter
- Macrophages, Peritoneal/immunology
- Melanoma, Experimental/genetics
- Melanoma, Experimental/immunology
- Melanoma, Experimental/therapy
- Mice
- Mice, Inbred C57BL
- Molecular Sequence Data
- Ovalbumin/immunology
- Protein Precursors/genetics
- Protein Precursors/isolation & purification
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/isolation & purification
- Recombinant Proteins/biosynthesis
- Recombinant Proteins/isolation & purification
- T-Lymphocytes, Cytotoxic/immunology
- Transfection
- Tumor Cells, Cultured
- Virulence Factors, Bordetella/genetics
- Virulence Factors, Bordetella/isolation & purification
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66
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Lo-Man R, Vichier-Guerre S, Bay S, Dériaud E, Cantacuzène D, Leclerc C. Anti-tumor immunity provided by a synthetic multiple antigenic glycopeptide displaying a tri-Tn glycotope. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 166:2849-54. [PMID: 11160353 DOI: 10.4049/jimmunol.166.4.2849] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In many cancer cells the alteration of glycosylation processes leads to the expression of cryptic carbohydrate moieties, which make them good targets for immune intervention. Identification of cancer-associated glycotopes as well as progress in chemical synthesis have opened up the way for the development of fully synthetic immunogens that can induce anti-saccharide immune responses. Here, we synthesized a dendrimeric multiple antigenic glycopeptide (MAG) containing the Tn Ag O:-linked to a CD4(+) T cell epitope. This MAG is based on three consecutive Tn moieties (tri-Tn) corresponding to the glycotope recognized by an mAb (MLS 128) produced against the LS180 colon carcinoma cell line. The Abs induced by this MAG recognized murine and human tumor cell lines expressing the Tn Ag. Prophylactic vaccination using MAG provided protection of mice against tumor challenge. When used in active specific immunotherapy, the MAG carrying the tri-Tn glycotope was much more efficient than the mono-Tn analogue in promoting the survival of tumor-bearing mice. Furthermore, in active specific immunotherapy, a linear glycopeptide carrying two copies of the tri-Tn glycotope was shown to be poorly efficient compared with the dendrimeric MAG. Therefore, both the clustering of carbohydrate Ags and the way they are displayed seem to be important parameters for stimulating efficient anti-saccharide immune responses.
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MESH Headings
- Animals
- Antibodies, Neoplasm/biosynthesis
- Antibodies, Neoplasm/metabolism
- Antigens, Tumor-Associated, Carbohydrate/administration & dosage
- Antigens, Tumor-Associated, Carbohydrate/chemistry
- Antigens, Tumor-Associated, Carbohydrate/immunology
- Antigens, Tumor-Associated, Carbohydrate/metabolism
- Antineoplastic Agents/administration & dosage
- Antineoplastic Agents/chemical synthesis
- Antineoplastic Agents/immunology
- Antineoplastic Agents/metabolism
- Binding Sites, Antibody
- Breast Neoplasms/immunology
- Breast Neoplasms/prevention & control
- CD4-Positive T-Lymphocytes/immunology
- Cancer Vaccines/administration & dosage
- Cancer Vaccines/chemical synthesis
- Cancer Vaccines/immunology
- Carbohydrate Sequence
- Epitopes, T-Lymphocyte/administration & dosage
- Epitopes, T-Lymphocyte/chemistry
- Epitopes, T-Lymphocyte/immunology
- Epitopes, T-Lymphocyte/metabolism
- Female
- Glycopeptides/administration & dosage
- Glycopeptides/chemical synthesis
- Glycopeptides/immunology
- Glycopeptides/metabolism
- Humans
- Immunotherapy, Active
- Injections, Intraperitoneal
- Jurkat Cells
- Mice
- Mice, Inbred BALB C
- Molecular Sequence Data
- Neoplasm Transplantation
- Poliovirus/immunology
- Tumor Cells, Cultured
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Coëffier E, Clément JM, Cussac V, Khodaei-Boorane N, Jehanno M, Rojas M, Dridi A, Latour M, El Habib R, Barré-Sinoussi F, Hofnung M, Leclerc C. Antigenicity and immunogenicity of the HIV-1 gp41 epitope ELDKWA inserted into permissive sites of the MalE protein. Vaccine 2000; 19:684-93. [PMID: 11115689 DOI: 10.1016/s0264-410x(00)00267-x] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The highly conserved amino acid sequence ELDKWA of HIV-1 gp41 has been inserted into Escherichia coli MalE protein which had been shown to be an adequate carrier to present foreign epitopes to the immune system. We first investigated whether eight different permissive sites of MalE are able to tolerate an insertion of 7-50 residues encoding this epitope. Secondly, antigenicity of the epitope inserted in MalE protein was estimated from monoclonal antibody 2F5 binding analysis using the BIAcore(R) technology and its immunogenicity in mice was measured as the ability of hybrid proteins to elicit antibodies against a synthetic peptide containing this epitope. This study revealed a good correlation between the antigenicity of the inserted epitope and its immunogenicity. Increasing the length of the inserted epitope, as well as inserting multicopies of this epitope increased both its antigenicity and immunogenicity. However, none of the MalE hybrid proteins tested induced anti-HIV-1 neutralizing antibodies. This study strongly suggests that the capacity of the 2F5 epitope to induce neutralizing antibodies depends on the molecular context in which it is presented.
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68
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Badou A, Bennasser Y, Moreau M, Leclerc C, Benkirane M, Bahraoui E. Tat protein of human immunodeficiency virus type 1 induces interleukin-10 in human peripheral blood monocytes: implication of protein kinase C-dependent pathway. J Virol 2000; 74:10551-62. [PMID: 11044099 PMCID: PMC110929 DOI: 10.1128/jvi.74.22.10551-10562.2000] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The clinical manifestations observed in human immunodeficiency virus type 1 (HIV-1)-infected patients are primarily due to the capacity of the virus and its components to inactivate the immune system. HIV-1 Tat protein could participate in this immune system disorder. This protein is secreted by infected cells of HIV-infected patients and is free in the plasma, where it can interact and be taken up by both infected and noninfected cells. In asymptomatic patients infected by HIV-1, production of interleukin-10 (IL-10), a highly immunosuppressive cytokine, is associated with disease progression to AIDS. In the present work, we tested the capacity of Tat to induce IL-10 production by peripheral blood monocytes of healthy donors. The results show that Tat causes the production of IL-10 in a dose- and stimulation time-dependent manner. Investigations of the mechanisms involved in signal transduction show that (i) the calcium pathway is not or only slightly involved in Tat-induced IL-10 production, (ii) the protein kinase C pathway plays an essential role, and (iii) monocyte stimulation by Tat results in the intranuclear translocation of transcription factor NF-kappaB and in the induction of phosphorylation of the mitogen-activated protein kinases ERK1 and ERK2; activation of these two potential substrates of protein kinase C is required for the production of IL-10. Finally, our results suggest that the effect of Tat is exerted at the membrane level and that the active domain is located within N-terminal residues 1 to 45. This production of IL-10 induced by Tat could participate in the progression of HIV infection to AIDS.
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Leclerc C, Webb SE, Daguzan C, Moreau M, Miller AL. Imaging patterns of calcium transients during neural induction in Xenopus laevis embryos. J Cell Sci 2000; 113 Pt 19:3519-29. [PMID: 10984442 DOI: 10.1242/jcs.113.19.3519] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Through the injection of f-aequorin (a calcium-sensitive bioluminescent reporter) into the dorsal micromeres of 8-cell stage Xenopus laevis embryos, and the use of a Photon Imaging Microscope, distinct patterns of calcium signalling were visualised during the gastrulation period. We present results to show that localised domains of elevated calcium were observed exclusively in the anterior dorsal part of the ectoderm, and that these transients increased in number and amplitude between stages 9 to 11, just prior to the onset of neural induction. During this time, however, no increase in cytosolic free calcium was observed in the ventral ectoderm, mesoderm or endoderm. The origin and role of these dorsal calcium-signalling patterns were also investigated. Calcium transients require the presence of functional L-type voltage-sensitive calcium channels. Inhibition of channel activation from stages 8 to 14 with the specific antagonist R(+)BayK 8644 led to a complete inhibition of the calcium transients during gastrulation and resulted in severe defects in the subsequent formation of the anterior nervous system. BayK treatment also led to a reduction in the expression of Zic3 and geminin in whole embryos, and of NCAM in noggin-treated animal caps. The possible role of calcium transients in regulating developmental gene expression is discussed.
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70
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Sedlik C, Dadaglio G, Saron MF, Deriaud E, Rojas M, Casal SI, Leclerc C. In vivo induction of a high-avidity, high-frequency cytotoxic T-lymphocyte response is associated with antiviral protective immunity. J Virol 2000; 74:5769-75. [PMID: 10846055 PMCID: PMC112070 DOI: 10.1128/jvi.74.13.5769-5775.2000] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Many approaches are currently being developed to deliver exogenous antigen into the major histocompatibility complex class I-restricted antigen pathway, leading to in vivo priming of CD8(+) cytotoxic T cells. One attractive possibility consists of targeting the antigen to phagocytic or macropinocytic antigen-presenting cells. In this study, we demonstrate that strong CD8(+) class I-restricted cytotoxic responses are induced upon intraperitoneal immunization of mice with different peptides, characterized as CD8(+) T-cell epitopes, bound to 1-microm synthetic latex microspheres and injected in the absence of adjuvant. The cytotoxic response induced against a lymphocytic choriomeningitis virus (LCMV) peptide linked to these microspheres was compared to the cytotoxic T-lymphocyte (CTL) response obtained upon immunization with the nonreplicative porcine parvovirus-like particles (PPV:VLP) carrying the same peptide (PPV:VLP-LCMV) previously described (C. Sedlik, M. F. Saron, J. Sarraseca, I. Casal, and C. Leclerc, Proc. Natl. Acad. Sci. USA 94:7503-7508, 1997). We show that the induction of specific CTL activity by peptides bound to microspheres requires CD4(+) T-cell help in contrast to the CTL response obtained with the peptide delivered by viral pseudoparticles. Furthermore, PPV:VLP are 100-fold more efficient than microspheres in generating a strong CTL response characterized by a high frequency of specific T cells of high avidity. Moreover, PPV:VLP-LCMV are able to protect mice against a lethal LCMV challenge whereas microspheres carrying the LCMV epitope fail to confer such protection. This study demonstrates the crucial involvement of the frequency and avidity of CTLs in conferring antiviral protective immunity and highlights the importance of considering these parameters when developing new vaccine strategies.
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71
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Dadaglio G, Moukrim Z, Lo-Man R, Sheshko V, Sebo P, Leclerc C. Induction of a polarized Th1 response by insertion of multiple copies of a viral T-cell epitope into adenylate cyclase of Bordetella pertussis. Infect Immun 2000; 68:3867-72. [PMID: 10858196 PMCID: PMC101660 DOI: 10.1128/iai.68.7.3867-3872.2000] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The adenylate cyclase (CyaA) of Bordetella pertussis delivers the N-terminal catalytic domain into the cytosol of a large number of eukaryotic cells, in particular, professional antigen-presenting cells. This allows the delivery of CD8(+) T-cell epitopes to the major histocompatibility complex class I presentation pathway. We have previously shown that immunization of mice with CyaA carrying a single CD8(+) T-cell epitope leads to antiviral protection as well as to protective and therapeutic antitumor immunity associated with the induction of specific cytotoxic T-lymphocyte (CTL) responses. Here, we evaluated the capacity of CyaA carrying one to four copies of the CD8(+) CD4(+) T-cell epitope from the nucleoprotein of the lymphocytic choriomeningitis virus to induce T-cell responses. Both CTL and Th1-like specific responses were detected in mice immunized with recombinant CyaA with or without adjuvant. Although the insertion of the larger peptides resulted in partial loss of the invasive capacity of recombinant CyaA, insertion of several copies of the same epitope led to a strong enhancement of Th1 responses and, to a lesser degree, CTL responses. These results underscore the potency of CyaA for vaccine design with a new impact on diseases in which the Th1 response has been described to have a beneficial effect.
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Leclerc C, Lesage AD, Ricard N, Lecomte T, Cyr M. Assessment of a new rehabilitative coping skills module for persons with schizophrenia. THE AMERICAN JOURNAL OF ORTHOPSYCHIATRY 2000; 70:380-388. [PMID: 10953784 DOI: 10.1037/h0087644] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A rehabilitative coping skills module employing problem solving and cognitive behavioral therapy and an experimental repeated-measure design was tested on 55 randomly selected persons severely handicapped by schizophrenia, most of whom had lived almost half of their lives in psychiatric wards. Unlike the control group of 44 comparable schizophrenics, the experimental group exhibited a significant decrease in delusions and increase in self-esteem, and maintained hygiene levels.
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Leclerc C, Guerrier P, Moreau M. Role of dihydropyridine-sensitive calcium channels in meiosis and fertilization in the bivalve molluscs Ruditapes philippinarum and Crassostrea gigas. Biol Cell 2000; 92:285-99. [PMID: 11043416 DOI: 10.1016/s0248-4900(00)01069-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Prophase-arrested oocytes of Ruditapes philippinarum can not be fertilized or stimulated by a depolarizing agent such as an excess of KCl, in contrast to the situation found in Crassostrea gigas. We have performed a comparative study between the two situations found in these species. In vitro, both of these oocytes can be triggered to reinitiate meiosis following a treatment by serotonin which promotes an intracellular calcium surge. Ruditapes and Crassostrea oocytes further arrest in metaphase I, at which stage they can be either activated by sperm or by excess KCl. These treatments trigger an intracellular calcium increase. This suggests that functional voltage-operated Ca2+ channels are expressed in Ruditapes during the course of maturation between prophase and metaphase I. Results obtained using pharmacological tools and direct binding of specific dihydropyridines, strongly suggest that these channels are dihydropyridine-sensitive calcium channels. In Ruditapes they become functional after 5-HT stimulation, their number increasing before GVBD. In Crassostrea the dihydropyridine-sensitive Ca2+ channels are already present at prophase stage and their density is constant from prophase to metaphase I. Moreover, we have shown for Ruditapes and Crassostrea that: 1) the addition of 10 microM of S(-)BayK8644, an agonist of dihydropyridine-sensitive calcium channels to metaphase-arrested oocytes releases them from metaphase block; and 2) incubating these oocytes with nicardipine, a potent blocker of dihydropyridine-sensitive Ca2+ channels, inhibits both their activation by excess KCl or fertilization. Taken together these data suggest that the absence of dihydropyridine-sensitive Ca2+ channels in the membrane of prophase-arrested oocytes of Ruditapes may account for their inability to be fertilized at this stage, while the presence of dihydropyridine-sensitive Ca2+ channels in prophase-arrested oocytes of Crassostrea may explain their fertilizability at this stage.
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Lo-Man R, Langeveld JP, Dériaud E, Jehanno M, Rojas M, Clément JM, Meloen RH, Hofnung M, Leclerc C. Extending the CD4(+) T-cell epitope specificity of the Th1 immune response to an antigen using a Salmonella enterica serovar typhimurium delivery vehicle. Infect Immun 2000; 68:3079-89. [PMID: 10816447 PMCID: PMC97535 DOI: 10.1128/iai.68.6.3079-3089.2000] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We analyzed the CD4 T-cell immunodominance of the response to a model antigen (Ag), MalE, when delivered by an attenuated strain of Salmonella enterica serovar Typhimurium (SL3261*pMalE). Compared to purified MalE Ag administered with adjuvant, the mapping of the peptide-specific proliferative responses showed qualitative differences when we used the Salmonella vehicle. We observed the disappearance of one out of eight MalE peptides' T-cell reactivity upon SL3261*pMalE immunization, but this phenomenon was probably due to a low level of T-cell priming, since it could be overcome by further immunization. The most striking effect of SL3261*pMalE administration was the activation and stimulation of new MalE peptide-specific T-cell responses that were silent after administration of purified Ag with adjuvant. Ag presentation assays performed with MalE-specific T-cell hybridomas showed that infection of Ag-presenting cells by this intracellular attenuated bacterium did not affect the processing and presentation of the different MalE peptides by major histocompatibility complex (MHC) class II molecules and therefore did not account for immunodominance modulation. Thus, immunodominance of the T-cell response to microorganisms is governed not only by the frequency of the available T-cell repertoire or the processing steps in Ag-presenting cells that lead to MHC presentation but also by other parameters probably related to the infectious process and to the bacterial products. Our results indicate that, upon infection by a microorganism, the specificity of the T-cell response induced against its Ags can be much more effective than with purified Ags and that it cannot completely be mimicked by purified Ags administered with adjuvant.
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Himmelrich H, Lo-Man R, Winter N, Guermonprez P, Sedlik C, Rojas M, Monnaie D, Gheorghiu M, Lagranderie M, Hofnung M, Gicquel B, Clément JM, Leclerc C. Immune responses induced by recombinant BCG strains according to level of production of a foreign antigen: malE. Vaccine 2000; 18:2636-47. [PMID: 10781849 DOI: 10.1016/s0264-410x(00)00070-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A variety of viral, bacterial and parasitic antigens have been expressed in BCG and the capacity of these recombinant bacteria to induce immune responses has been well documented. However, little is known about the parameters influencing the induction of immune responses by recombinant BCG (rBCG), such as level of production and localization of the recombinant antigen. In the present study, we have constructed several rBCG strains expressing the malE gene from Escherichia coli which is either secreted or targeted to the cytoplasm or plasma membrane. Expression of malE was quantified by ELISA and localization was analyzed by flow cytometry. Even when using the same promoter, levels of cytoplasmic or membrane MalE production were far less than those from secreting strains using either mycobacterial or E. coli secretion signals. Stronger and more rapid immune responses were induced by rBCG strains with the highest levels of secreted MalE compared to cytoplasmic or membrane constructs, including both good humoral and proliferative responses in BALB/c, C57BL6 and even C3H mice, previously shown to be poor MalE responders. These results suggest that the levels of foreign antigen production play an important role in the induction of immune responses by rBCG strains.
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