Biomedical subjects

Wichard Vogel

Publications and source records attributed to Wichard Vogel.

7 recordsLinked to original sources

PubMed2005

Infection of human CD34+ progenitor cells with Bartonella henselae results in intraerythrocytic presence of B. henselae.

Although there is evidence that endothelial cells are important targets for human pathogenic Bartonella species, the primary niche of infection is unknown. Here we elucidated whether human CD34+ hematopoietic progenitor cells (HPCs) internalize B. henselae and may serve as a potential niche of the pathogen. We showed that B. henselae does not adhere to or invade human erythrocytes. In contrast, B. henselae invades and persists in HPCs as shown by gentamicin protection assays, confocal laser scanning microscopy (CLSM), and electron microscopy (EM). Fluorescence-activated cell sorting (FACS) analysis of glycophorin A expression revealed that erythroid differentiation of HPCs was unaffected following infection with B. henselae. The number of intracellular B. henselae continuously increased over a 13-day period. When HPCs were infected with B. henselae immediately after isolation, intracellular bacteria were subsequently detectable in differentiated erythroid cells on day 9 and day 13 after infection, as shown by CLSM, EM, and FACS analysis. Our data provide, for the first time, evidence that a bacterial pathogen is able to infect and persist in differentiating HPCs, and suggest that HPCs might serve as a potential primary niche in Bartonella infections.

Angiomatosis, Bacillary↗

PubMed2004

Myeloma cell contamination of peripheral blood stem-cell grafts can predict the outcome in multiple myeloma patients after high-dose chemotherapy and autologous stem-cell transplantation.

PURPOSE: High-dose chemotherapy with hematopoietic stem-cell rescue is increasingly being used in the treatment of multiple myeloma. Bone marrow and also peripheral blood stem-cell (PBSC) grafts contain measurable quantities of plasma cells, the biological significance of which is unknown. METHODS: Patients with multiple myeloma were mobilized with chemotherapy and filgrastim. The number of CD38++/CD138+ cells/kg in the grafts for autologous transplantation was determined by flow cytometry. Patients were stratified into two groups (threshold 4.5 x 10(5) plasma cells kg(-1)) of reinfused plasma cells in the first autologous graft. RESULTS: The median statistical progression-free survival was 14 months (4-34 months) in the high-contamination group (>4.5 x 10(5) plasma cells kg(-1)) compared to 26 months (4-43 months) in the low-contamination group (<4.5 x 10(5) plasma cells kg(-1), P =0.0096). Patients with 13q deletion were more frequently found to have a high contamination of the stem-cell graft with malignant plasma cells. CONCLUSIONS: Patients with graft contamination of more than 4.5 x 10(5) plasma cells kg(-1) had a high risk of early disease progression after high-dose chemotherapy. In vivo tumor cell purging prior to mobilization chemotherapy might be one strategy to improve the time to progression of high-risk patients.

Adult↗

PubMed2004

Additional transplantation of ex vivo generated megakaryocytic cells after high-dose chemotherapy.

The additional transplantation of ex vivo generated hematopoietic (post)-progenitor cells represents a possible approach to ameliorate high-dose chemotherapy induced cytopenia. We investigated the feasibility of the large-scale expansion and transplantation of autologous megakaryocytic cells in four patients with advanced solid tumors. Up to 1,460x10(6) ex vivo generated cells were administered without adverse effects but no clear cut effect on platelet recovery was observed.

Antigens, CD34↗

PubMed2003

Expression of her-2/neu on acute lymphoblastic leukemias: implications for the development of immunotherapeutic approaches.

Her-2/neu is a tumor-associated antigen that is expressed on several adenocarcinomas and correlates with poor prognosis. In a previous study (H. J. Bühring et al., Blood, 86: 1916-1923, 1995), it has been demonstrated that Her-2/neu expression can be detected on blast cells from patients with hematological malignancies including acute lymphoblastic leukemia (ALL). Here, we show that Her-2/neu-specific CTLs induced in vitro using peptide-pulsed dendritic cells efficiently lyse primary ALL blasts constitutively expressing both Her-2/neu and human leukocyte antigen A2 in an antigen-specific and MHC-restricted manner. Furthermore, we analyzed the feasibility of this approach in an autologous setting and induced Her-2/neu-specific CTLs using dendritic cells generated from peripheral blood mononuclear cells from an ALL patient that were pulsed with peptides or transfected with in vitro-transcribed Her-2/neu mRNA. Our data demonstrate that Her-2/neu could be used as a potential target for the application of Her-2/neu-directed treatment strategies in ALL including vaccination approaches.

Antigens, CD34↗

PubMed2003

Heterogeneity among human bone marrow-derived mesenchymal stem cells and neural progenitor cells.

BACKGROUND AND OBJECTIVES: Mesenchymal stem cells (MSC) and neural progenitor cells (NPC) are pluripotent cells. The former can give rise to myocytes, chondrocytes, adipocytes, and osteogenic cells, while the latter can give rise to astrocytes, neurons, and oligodendrocytes. The aim of this study was to analyze and compare the antigen expression patterns of MSC and NPC. DESIGN AND METHODS: Human bone marrow-derived MSC and NPC were analyzed by flow cytometry and immunocytochemistry using a variety of unique monoclonal antibodies (57D2, W4A5, W8B2) generated in our laboratory. In addition, the expression profile of CD antigens and intracellular differentiation markers was analyzed. RESULTS: We show for the first time that CD10+, CD13+, CD61+, CD90+, CD105 (endoglin)+, CD45-, CD34-, and CD133- MSC also expressed CD109, CD140b (PDGF-RB), CD164, and CD172a (SIRPa). In addition, we found heterogeneity of MSC as demonstrated by the preferential expression of nestin and W8B2 antigen on distinct MSC subpopulations. Morphologically, these populations comprised small single cells and larger cells with polygonal appearance. NPC expressed high levels of CD56, CD90 and nestin and moderate levels of CD15, W4A5, and 57D2 antigens. In contrast, CD133 and CD172 were found only on NPC subpopulations. INTERPRETATION AND CONCLUSIONS: Our data demonstrate nestin expression in most NPC as well as in immature MSC subpopulations. MSC and NPC subpopulations can now be distinguished using our novel antibodies W8B2, 57D2, and W4A5.

Antigens, CD↗

PubMed2003

Differential in vivo and in vitro expression of ED-B+ fibronectin in adult human hematopoiesis.

Fibronectin in general is involved in adhesion and maturation of the erythroid lineage, in megakaryopoiesis and in the differentiation of human multipotent hematopoietic progenitor cells. However, little information exists about the expression of the oncofetal fibronectin isoform containing the ED-B domain (ED-B+ fn) in adult human hematopoiesis. The study was aimed to analyze the ED-B+ fn expression in normal human bone marrow cells by immunocytochemistry, flow cytometry and reverse-transcriptase polymerase chain reaction. The in vivo results were compared to ED-B+ fn expression in human long-term bone marrow cultures (LTBMC), cytokine supported expansion cultures of CD34+ peripheral blood progenitor cells (PBPC) and in leukemic cell lines with megakaryocytic characteristics (K562, CMK). ED-B+ fn protein was immunocytochemically demonstrated in normal bone marrow megakaryocytes as well as in megakaryocytic progenitor/precursor cells generated ex vivo from PBPC but we failed to detect ED-B+ fn mRNA. It was strongly expressed in LTBMC (RNA and protein). Analysis of human bone marrow mononuclear cells by flow cytometry and confocal microscopy revealed only cytoplasmic ED-B+ fn. The SCF/TPO induced megakaryocytic differentiation of ED-B+ fn negative CMK cells is associated with an increase of large megakaryocytes followed by an intracellular accumulation of ED-B+ fn mRNA and protein. We conclude that in normal human hematopoiesis ED-B+ fn protein expression and intracellular accumulation is restricted to differentiation of megakaryocytes. Low-abundant synthesis, intracellular accumulation and failure of membrane exposure might be due to a function during early events of wound healing (formation of a platelet-rich provisional extracellular matrix).

Bone Marrow↗

PubMed2002

Monoclonal antibody 9C4 recognizes epithelial cellular adhesion molecule, a cell surface antigen expressed in early steps of erythropoiesis.

OBJECTIVE: Monoclonal antibody (mAb) 9C4 detects a surface antigen expressed on immature erythroid progenitor cells and epithelial tumor cell lines. The aim of this study was to identify the recognized surface antigen and to analyze a potential role of this molecule in early steps of erythropoiesis. MATERIALS AND METHODS: A pituitary-derived retroviral cDNA library was used to generate viruses and infect NIH-3T3 fibroblasts. The transfected cells were stained with mAb 9C4; positive cells were sorted by FACS; and a clonal cell line binding mAb 9C4 was established. cDNA encoding the 9C4-binding protein was amplified by polymerase chain reaction and cloned. Reactivity of mAb 9C4 with human bone marrow (BM) cells was analyzed by flow cytometry. RESULTS: Sequence analysis of the isolated cDNA uncovered a 100% identity with the epithelial cellular adhesion molecule (Ep-CAM). Two-color flow cytometric analysis revealed that almost 100% of Ep-CAM(+) BM cells coexpressed CD105, E-cadherin, and high levels of CD71. Fractions of Ep-CAM(+) BM cells also were CD34(+) but lacked glycophorin A expression, suggesting that Ep-CAM(+) cells represent immature erythroid cells. Reverse transcriptase polymerase chain reaction analysis of BM mononuclear cells revealed that the 9C4(+) erythroblast population but not the 9C4(-) fraction expressed Ep-CAM mRNA. Peripheral blood CD34(+) cells induced in vitro to differentiate into the erythroid lineage showed strong Ep-CAM expression on days 3 to 7 of culture. The addition of Ep-CAM-specific mAbs 9C4 or KS1/4 to the culture resulted in two- to three-fold up-regulation of Ep-CAM protein expression. CONCLUSION: mAb 9C4 recognizes Ep-CAM, a molecule expressed in the early steps of erythropoiesis.

3T3 Cells↗