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C Dezutter-Dambuyant

Publications and source records attributed to C Dezutter-Dambuyant.

At least 19 recordsLinked to original sources
PubMed1997

Immunophenotypic characterization of feline Langerhans cells.

To carry out the characterization of feline Langerhans cells (LC), first described in 1994, we used a panel of monoclonal antibodies (MAb) known to react with human, canine and feline leukocyte membrane antigens (Ag). The immunolabeling was performed, at light microscope level, on frozen sections of feline skin and labial mucosa using an avidin-biotin-peroxidase technique, and at electron microscope level on epidermal cell suspensions using an immunogold technique. Out of the 52 MAb tested, six labeled basal or suprabasal DC cells in the frozen sections, either in epidermis or lip epithelium: MHM23 (anti-human CD18), CVS20 and vpg3 (respectively anti-canine and feline-major histocompatibility complex class II molecules), vpg5 (anti-feline leukocytes), vpg39 (anti-feline CD4) and Fel5F4 (anti-feline CD1a). These six MAb were used on suspensions, and labeled cells which showed no desmosomes or melanosomes, but contained 'zipper-like' structures similar to Birbeck granules (BG) in their cytoplasm, revealing they were LC. Consequently, feline LC are CD18-positive (CD18+), major histocompatibility complex class II-positive (Class II+), CD1a-positive (CD1a+), vpg5-positive (vg5+) and CD4-positive (CD4+). This immunophenotypic and ultrastructural characterization demonstrates that feline LC share many characteristics with their human counterparts, a fact that will allow us to study the role of feline LC in certain feline diseases such as Feline Immunodeficiency Virus (FIV) infection, since it has been shown that human LC cells are HIV-permissive, and to establish an animal model for human AIDS.

Animals↗
PubMed1997

Limbal conjunctival Langerhans cell density in ocular cicatricial pemphigoid: an indirect immunofluorescence study on Dispase-split conjunctiva.

PURPOSE: To evaluate limbal conjunctival Langerhans cell density in ocular cicatricial pemphigoid patients versus normal controls. Langerhans cells obviously play a major role in T-cell activation and are involved in corneal and conjunctival inflammatory diseases. METHODS: We used a protease (Dispase II) on inferior limbal conjunctival biopsies to separate the epithelium from the substantia propria and performed indirect immunofluorescence to analyze CD1a+ (a specific Langerhans cell surface antigen) cell density on flat-mounted epithelial sheets obtained from 30 normal controls and 11 patients presenting with ocular cicatricial pemphigoid. RESULTS: This technique was quick and reproducible. The mean Langerhans cell density in normal limbal conjunctiva was 272 +/- 37 cells/mm2. It was significantly higher in ocular cicatricial pemphigoid patients: 386 +/- 43 cells/mm2 (p = 0.001). CONCLUSIONS: Conjunctival Langerhans cell density in ocular surface inflammatory diseases can best be evaluated by indirect immunofluorescence, following epithelial sheet separation from the substantia propria, using Dispase II.

Aged↗
PubMed1997

Quantitative assessment of feline epidermal Langerhans cells.

The densities of feline epidermal dendritic cells expressing CD18, MHC class II and CD1a antigens were determined for four anatomical locations in 19 cats of European breed in blind conditions. The densities (+/- SD) of CD1a+ Langerhans cells in the skin of the abdominal wall (269 +/- 68 cells/mm2), the back (363 +/- 19), the internal side of the ear (572 +/- 30) and the external side of the ear (502 +/- 32) were significantly different, with young and old animals displaying less stained cells than adults. No significant differences in the mean densities were found with regard to sex, colour or antibody used.

Abdomen↗
PubMed1996

CD34+ hematopoietic progenitors from human cord blood differentiate along two independent dendritic cell pathways in response to GM-CSF+TNF alpha.

Human dendritic cells (DC) can now be generated in vitro in large numbers by culturing CD34+ hematopoietic progenitors in presence of GM-CSF+TNF alpha for 12 d. The present study demonstrates that cord blood CD34+ HPC indeed differentiate along two independent DC pathways. At early time points (day 5-7) during the culture, two subsets of DC precursors identified by the exclusive expression of CD1a and CD14 emerge independently. Both precursor subsets mature at day 12-14 into DC with typical morphology and phenotype (CD80, CD83, CD86, CD58, high HLA class II). CD1a+ precursors give rise to cells characterized by the expression of Birbeck granules, the Lag antigen and E-cadherin, three markers specifically expressed on Langerhans cells in the epidermis. In contrast, the CD14+ progenitors mature into CD1a+ DC lacking Birbeck granules, E-cadherin, and Lag antigen but expressing CD2, CD9, CD68, and the coagulation factor XIIIa described in dermal dendritic cells. The two mature DC were equally potent in stimulating allogeneic CD45RA+ naive T cells. Interestingly, the CD14+ precursors, but not the CD1a+ precursors, represent bipotent cells that can be induced to differentiate, in response to M-CSF, into macrophage-like cells, lacking accessory function for T cells. Altogether, these results demonstrate that different pathways of DC development exist: the Langerhans cells and the CD14(+)-derived DC related to dermal DC or circulating blood DC. The physiological relevance of these two pathways of DC development is discussed with regard to their potential in vivo counterparts.

Antigens, CD1↗
PubMed1996

Expression and function of B7-1 (CD80) and B7-2 (CD86) on human epidermal Langerhans cells.

In addition to T cell receptor triggering, activation of T cells requires costimulatory signals that have been shown to be mainly initiated through CD28. We analyzed the expression and function of the two ligands for CD28, B7-1 (CD80) and B7-2 (CD86), on human Langerhans cells (LC), the antigen-presenting cells from epidermis. Human LC freshly isolated from epidermis (fLC) expressed significant level of B7-2, which was increased upon a short culture in vitro. In contrast, B7-1 was undetectable on fLC but appeared at the cell surface after a 3-day culture in vitro. Pre-incubation of 18-h cultured LC with anti-B7-2 monoclonal antibodies (mAB) was sufficient to abrogate the binding of CTLA4-Ig fusion protein, while a combination of both mAB against B7-1 and B7-2 was necessary to obtain a complete inhibition of CTLA4-Ig binding on 3-day cultured LC, showing the absence of a third CTLA4 ligand. The function of B7-1 and B7-2 on human LC has been analyzed by adding mAb at the beginning of mixed epidermal cell lymphocyte reactions. Anti-B7-2 mAb and CTLA4-Ig, but not anti-B7-1 mAb, strongly inhibited allogenic. as well as recall antigen-induced T cell proliferation supported by fLC or 3-day cultured LC. Collectively, these results demonstrate that B7-2 is the major ligand for CD28/CTLA4 at the LC surface and that it plays a crucial role in human LC co-stimulatory function with little, if any, dependence of B7-1 expression.

Antigen Presentation↗
PubMed1996

Expression of gastrin-releasing peptide receptor in human skin.

Bombesin-related peptides are expressed in the skin of batrachians and mammals. As gastrin-releasing peptide belongs to this family, we searched for the presence and distribution of gastrin-releasing peptide receptors (GRPr) in the skin of healthy human adults by immunohistochemistry, flow cytometry and electron microscopy. The results indicated that GRPr are expressed on nerves and vessels in the dermis, on eccrine sweat glands, sebaceous glands and erector pili muscle. Within epidermis, staining was localized only on basal and suprabasal layer cells, or in the whole epidermis, according to the samples studied. Interestingly, suprabasal epidermal dendritic cells occasionally showed a strong labelling. Some of these epidermal dendritic cells were identified as Langerhans' cells by immunoelectron microscopy studies. Flow cytometry analysis of crude epidermal cell suspensions resulted in the expression of GRPr on about 43% of the cells. Therefore, we investigated whether human GRPr could modulate Langerhans' cells antigen-presenting functions. For this purpose, we added increasing concentrations of GRP (10(-12) to 10(-5) M) to mixed epidermal cell lymphocyte reactions. Allogeneic T-cell proliferation was not significantly modified when added to GRP-pretreated epidermal cells. In conclusion, we demonstrated the presence of GRPr in human skin, suggesting that GRP may modulate epidermal cell functions but does not modify antigenic presentation.

Adult↗
PubMed1995

Human dendritic Langerhans cells generated in vitro from CD34+ progenitors can prime naive CD4+ T cells and process soluble antigen.

Earlier studies have concluded that fresh Langerhans cells (LC) are able to capture and process native Ags, whereas cultured LC have lost these functions while acquiring the capacity to prime naive T cells. Herein we studied the functions of human dendritic/Langerhans cells (d-Lc) generated in vitro by culturing CD34+ hemopoietic progenitor cells in the presence of granulocyte-macrophage CSF (GM-CSF) + TNF-alpha. Less than 50 d-Lc were found to strongly stimulate the proliferation of 2.5 x 10(4) allogeneic naive CD4+ T cells. Furthermore, six to 50 d-Lc induced half-maximal proliferation of naive syngeneic CD4+ cord blood T cells, in the presence of picomolar concentrations of superantigens. During the alloreaction, the CD4+ T cells were expanded up to 100-fold within two successive stimulation cycles with the same d-Lc, and the recovered T cells were specific for the d-Lc alloantigen. HLA-matched tetanus toxoid (TT)-specific T cell clones were found to proliferate in response to TT presented by CD1a+ d-Lc. Finally, electron microscopy demonstrated that CD1a+ d-Lc were able to capture an Ag (gold-labeled Igs) through receptor-mediated endocytosis. Thus, in vitro generated d-Lc can prime naive T cells and process native Ags, a property that might eventually prove useful for priming Ag-specific naive T cells for cellular immunotherapy.

Adult↗
PubMed1995

Expression of ICAM-3 on human epidermal dendritic cells.

Three counter-receptors for LFA-1 of the immunoglobulin family have been discovered: ICAM-1, ICAM-2, and ICAM-3. Despite their homologies, their patterns of expression suggest specialized roles. The finding that ICAM-3 is much better expressed than other LFA-1 ligands on monocytes and resting T cells, and that this discovery may be important in the initiation of immune responses prompted us to search for the expression of ICAM-3 by human epidermal Langerhans cells (LC). Six out of eight different ICAM-3 monoclonal antibodies were found to be reactive with epidermal LC. Immunoelectron-microscopy staining revealed that 100% of freshly-isolated, typical Birbeck granules containing LC expressed ICAM-3. After one day and three days of culture, 100% of LC still expressed ICAM-3, but the staining intensity was decreased by 58% and 76% respectively. Immunoprecipitation of 125I surface-labeled LC with anti-ICAM-3 antibodies revealed a polypeptide with apparent M(r) of 122,000-125,000. To determine whether ICAM-3 was involved in LC function, mixed epidermal cell-lymphocyte reactions were performed with freshly isolated LC in the presence of various concentrations of different anti-ICAM-3 antibodies. Among the different antibodies tested, HP2/19 and CBR-IC3/1 were found to partially block the reaction in a dose-dependent manner, suggesting that ICAM-3 represents a new molecule involved in the initiation of the immune response driven by epidermal LC.

Antibodies, Monoclonal↗