Search results for "Bone Marrow"
showing 10 items of 538 documents
Dendritic Cells Lose Ability to Present Protein Antigen after Stimulating Antigen-Specific T Cell Responses, despite Upregulation of MHC Class II Exp…
2000
Abstract Immature dendritic cells (DC) take up, process and present protein antigens; mature DC are specialized for stimulating primary T cell responses with increased expression of MHC class II and co-stimulatory molecules, but are incapable of processing and presenting soluble protein. The current study examined whether maturation of DC is triggered by T cell recognition of antigens presented by immature DC. Human DC derived from CD34+ progenitor cells by culture with granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-6 (IL-6) in serum-free medium could prime naive CD4+ T cells to keyhole limpet hemocyanin (KLH) and ovalbumin (OVA). The cultured DC retained the abil…
Frequency-Analysis of Precursors of Cytotoxic T Lymphocytes in Radiation Chimeras: Enumeration of Antigenspecific CTL-P Restricted to Thymic MHC- and…
1984
The mechanisms controlling the acquisition of T cell restriction specificity and immunocompetence are, despite of numerous investigations, not well understood. From studies of the CTL-immune responsiveness in thymus- and bone marrow-grafted chimeric mice, it became apparent, that it is the thymus which is crucial not only for the maturation or T cells, but also for the specificity repertoire of the T cells (1,2). From these data it was suggested, that during intra-thymic maturation both mutational events and positive selection mechanisms influence the repertoire such that only T cells restricted to thymic epithelial cell MHC determinants mature and will be exported to the peripheral lymphoi…
Histomorphological study of the bone regeneration capacity of platelet-rich plasma, bone marrow and tricalcium phosphate Experimental study on pigs
2009
Introduction: Bone defects are rather common after oral surgery and may prove difficult to repair. Objective: We provide a histomorphological analysis of the bone regenerative capacity of platelet-rich plasma at different concentrations and the extraction of platelet-rich bone marrow, compared with -tricalcium phosphate. Methodology: We performed an experimental study on 8 pigs, in which we performed trepanations of the mandible in order to place the materials to be studied. Using an electron microscope, we observed the samples obtained and took a series of photographs in order to analyze the samples through a gray-scale histogram system. Results: Ossification phenomena were present in 96% …
MEF2C and SOCS2 in stemness regulation
2015
The physiologic stemness of hematopoietic stem cells (HSC) relies on mechanisms constitutively active under steady state and is fundamental to maintain a lifelong HSC reservoir. On the other side, similar stemness features sustained by partially overlapping molecular circuits, which have recently come into focus, confer aggressive aggressiveness in leukemia clones. Suppressor of Cytokine Signalling 2 (SOCS2) belongs to the SOCS family, comprising eight members (SOCS1–7 and CIS) with similar structures, which are induced upon JAK/STAT activation and function as negative regulators. Recent evidences have demonstrated that SOCS2 is endowed with immunological functions in differentiated cells b…
Prevention of chemotherapy-induced anemia and thrombocytopenia by constant administration of stem cell factor.
2011
Abstract Purpose: Chemotherapy-induced apoptosis of immature hematopoietic cells is a major cause of anemia and thrombocytopenia in cancer patients. Although hematopoietic growth factors such as erythropoietin and colony-stimulating factors cannot prevent the occurrence of drug-induced myelosuppression, stem cell factor (SCF) has been previously shown to protect immature erythroid and megakaryocytic cells in vitro from drug-induced apoptosis. However, the effect of SCF in vivo as a single myeloprotective agent has never been elucidated. Experimental Design: The ability of SCF to prevent the occurrence of chemotherapy-induced anemia and thrombocytopenia was tested in a mouse model of cisplat…
Myeloid-Derived Suppressor Cells in Multiple Myeloma: Pre-Clinical Research and Translational Opportunities
2014
Immunosuppressive cells have been reported to play an important role in tumor-progression mainly because of their capability to promote immune-escape, angiogenesis, and metastasis. Among them, myeloid-derived suppressor cells (MDSCs) have been recently identified as immature myeloid cells, induced by tumor-associated inflammation, able to impair both innate and adaptive immunity. While murine MDSCs are usually identified by the expression of CD11b and Gr1, human MDSCs represent a more heterogeneous population characterized by the expression of CD33 and CD11b, low or no HLA-DR, and variable CD14 and CD15. In particular, the last two may alternatively identify monocyte-like or granulocyte-lik…
Transmission of angioimmunoblastic T-cell lymphoma by bone marrow transplant
2014
Accidental transmission of lymphoma by bone marrow transplant is a rarely reported event [1–5], since candidates are only accepted for hematopoietic stem cell donation after a work-up that routinel...
A new pericentric inv(8) in acute nonlymphocytic leukemia.
1993
Abstract Chromosome studies were carried out on unstimulated bone marrow cells from a patient with a diagnosis of acute nonlymphocytic leukemia (FAB M6 ANLL). Cytogenetic analysis revealed a mosaic chromosome pattern 46,XX46,XX,inv(8)(p21q24). This pericentric inversion has not been previously described in ANLL. Because, fragile sites, zinc finger gene loci, and the MYC protooncogene have been localized to band 8q24, a putative role for these sites and genes could be considered.
Release of IFNγ by Acute Myeloid Leukemia Cells Remodels Bone Marrow Immune Microenvironment by Inducing Regulatory T Cells
2022
Abstract Purpose: The stromal and immune bone marrow (BM) landscape is emerging as a crucial determinant for acute myeloid leukemia (AML). Regulatory T cells (Treg) are enriched in the AML microenvironment, but the underlying mechanisms are poorly elucidated. Here, we addressed the effect of IFNγ released by AML cells in BM Treg induction and its impact on AML prognosis. Experimental Design: BM aspirates from patients with AML were subdivided according to IFNG expression. Gene expression profiles in INFγhigh and IFNγlow samples were compared by microarray and NanoString analysis and used to compute a prognostic index. The IFNγ release effect on the BM microenvironment was investigated in me…
CD40 provides immune privilege to the bone marrow hematopoietic niche
2020
AbstractAllogeneic bone marrow transplantation remains the only therapeutic option for a wide range of hematological malignancies despite the risk of possible adverse, immune-related events, such as infection and acute graft-versus-host disease (aGVHD). aGVHD is characterized by T-cell activation, defective B-cell development and osteoblastic niche destruction in bone marrow (BM) among other issues. Transplant conditioning regimens cause excessive inflammatory cytokines production and impaired regulatory T-cell control of aberrant T-cell activation. Here, we show that mesenchymal cells (MSCs) upregulated CD40 upon irradiation at the expense of mesenchymal markers, and that CD40 endows MSC o…