Biomedical subjects

Jeanine Marquet

Publications and source records attributed to Jeanine Marquet.

4 recordsLinked to original sources

PubMed2003

A closed and single-use system for monocyte enrichment: potential for dendritic cell generation for clinical applications.

BACKGROUND: This study evaluated the ability of a modified cell separator (Cobe Spectra Apheresis) system to isolate monocytes (MOs) by elutriation. The evaluation was performed in two independent international laboratories. The capacity of collected MOs to differentiate into dendritic cells (DCs) was also assessed. STUDY DESIGN AND METHODS: MNCs from platelet apheresis residues were elutriated on a modified cell separator (Cobe Spectra Apheresis system) using a custom disposable set. Cells were separated according to their size and density. Recovery and purity of the collected cell product were evaluated by impedance counting and flow cytometry. DCs were differentiated in culture from the elutriated MOs and characterized by their surface markers and stimulatory capacity in a mixed WBC reaction assay. RESULTS: Six apheresis mononuclear cell products were used by each laboratory. The separation was achieved in less than 1 hour. Collected MOs had the potential to differentiate into DCs. CONCLUSION: The modified cell separator is an easy and fast device to obtain highly enriched MOs with a DC differentiation potential. The system is closed and employs a single-use disposable set and is more amenable to good tissue practice. This method could become a valuable tool for DC-based active immunotherapy.

Antigens, CD19↗

PubMed2002

Severe decrease in peripheral blood dendritic cells in hairy cell leukaemia.

Clinical studies in hairy cell leukaemia (HCL) have linked the frequent occurrence of infections due to intracellular pathogens and a profound monocytopenia. More recently, dendritic cells (DC), a subset of which are related to monocytes, were shown to be the professional antigen-presenting cells which stimulate the adaptive immune response. Using membrane markers and flow cytometry, we determined in peripheral blood whether various DC subsets and monocytes were impaired in HCL. Lymphoid and myeloid DC were virtually absent in five HCL patients with active disease. After treatment, both DC and monocytes recovered slowly. The decrease in DC suggests that defective antigen presentation could affect susceptibility to intracellular pathogens in HCL.

Adult↗

PubMed2002

MAL expression in lymphoid cells: further evidence for MAL as a distinct molecular marker of primary mediastinal large B-cell lymphomas.

The MAL mRNA was initially identified during T-cell development and was later found in myelin-forming cells and certain polarized epithelial cell lines. It encodes a proteolipid believed to participate in membrane microdomains stabilization, transport machinery and signal transduction. Using a differential display reverse-transcription approach, we identified MAL as a distinct molecular marker of primary mediastinal large B-cell lymphoma compared with nonmediastinal diffuse large B-cell lymphomas. In the present study, we used immunohistochemistry to extend MAL expression analysis to normal lymphoid tissues; to 185 lymphomas representing most B, T, and Hodgkin lymphoma entities; and to the primary mediastinal large B-cell lymphoma derived B-cell line MedB-1. In addition, B and T cells from peripheral blood, tonsil, and spleen were analyzed by flow cytometry. Our results show that MAL is highly expressed in thymocytes, in a large percentage of peripheral CD4 T cells, and in a lower proportion of CD8 peripheral T cells. In the normal B-cell compartment, MAL expression appears to be restricted to a minor subpopulation of thymic medullary B cells and to occasional mature plasma cells located in the interfollicular areas of tonsil and lymph nodes. Among B-cell lymphomas (n = 110), MAL expression in tumor cells was observed in 21/33 primary mediastinal large B-cell lymphomas (70%) and in 3/5 plasmacytoma/myeloma, but not in all other B-cell lymphomas with the exception of 1/33 nonmediastinal diffuse large B-cell lymphomas. The MedB-1 B-cell line was also MAL positive. Among T-cell neoplasms, MAL was highly expressed in lymphoblastic tumors (5/6), whereas mature T-cell lymphomas were essentially MAL negative (27/28). Among 41 Hodgkin lymphomas, 3 nodular-sclerosing cases with mediastinal involvement showed MAL-positive Reed Sternberg cells. In conclusion, this study further supports thymic B cells as the putative normal counterpart of primary mediastinal large B-cell lymphomas and supports MAL as a distinct molecular marker of this lymphoma subtype among diffuse large B-cell lymphomas.

Antigens, CD↗

PubMedDate not supplied

IL-12 secreting dendritic cells are required for optimum activation of human secondary lymphoid tissue T cells.

Successful immunization requires that mature dendritic cells (mDCs) prime T cells in secondary lymphoid tissue (LT). Previously, the authors have shown that LT T cell activation has an increased costimulatory threshold for a proliferative response as compared with peripheral blood (PB) T cells. Therefore, to optimize mDC immunogenicity, DC maturation was studied using LT T cells as responders. While mDCs obtained with soluble CD40Ligand (sCD40L) or a sCD40L/IFNgamma combination similarly expressed the CD83 and CCR7 molecules on their membrane, only the latter secreted IL-12. sCD40L/IFNgamma mDCs, as compared with sCD40L mDCs, enhanced allogeneic LT T cell proliferation, LT CD4+ cell IFNgamma production and LT CD8+ cell cytotoxicity. Enhancement could be predominantly ascribed to IL-12 secreted by sCD40L/IFNgamma mDCs and to additional costimulatory signals as shown remarkably in the IFNgamma response when IL-12 was neutralized. Therefore, in addition to their membrane phenotype, mDCs to be used in immunization protocols should be assessed for IL-12 secretion as a surrogate marker for an optimum costimulatory potential.

Animals↗