Biomedical subjects

Manuela Wissler

Publications and source records attributed to Manuela Wissler.

6 recordsLinked to original sources

PubMed2005

Efficient marking of human cells with rapid but transient repopulating activity in autografted recipients.

Short-term hematopoietic reconstituting cells have been identified in mice, nonhuman primates, and among human cells that engraft xenogeneic hosts. We now present clonal marking data demonstrating a rapid but unsustained contribution of cultured human autografts to the initial phase of hematologic recovery in myeloablated patients. Three patients received transplants of granulocyte colony-stimulating factor-mobilized autologous peripheral blood (PB) cells, of which a portion (8%-25% of the CD34+ cells) had been incubated in vitro with growth factors (5 days) and clinical grade LN retrovirus (3-5 days). More than 9% of the clonogenic and long-term culture-initiating cells harvested were transduced. Semiquantitative and linear amplification-mediated polymerase chain reaction analyses of serial PB samples showed that marked white blood cells appeared in all 3 patients within 11 days and transiently constituted up to 0.1% to 1% of those produced in the first month. However, within another 2 to 9 months, marked cells had permanently decreased to very low levels. Analysis of more than 50 vector insertion sites showed none of the clones detected in the first month were active later. Eighty percent of inserts were located within or near genes, 2 near CXCR4. These findings provide direct evidence of cells with rapid but transient repopulating activity in patients and demonstrate their efficient transduction in vitro.

Biomarkers↗

PubMed2004

Clonal evidence for the transduction of CD34+ cells with lymphomyeloid differentiation potential and self-renewal capacity in the SCID-X1 gene therapy trial.

Immune function has been restored in 9 of 10 children with X-linked severe combined immunodeficiency by gamma c gene transfer in CD34+ cells. The distribution of both T-cell receptor (TCR) V beta family usage and TCR V beta complementarity-determining region 3 (CDR3) length revealed a broadly diversified T-cell repertoire. Retroviral integration site analysis in T cells demonstrated a high number of distinct insertion sites, indicating polyclonality of genetically corrected cell clones, in all patients. Detection of gamma c transgene expression on patients' mature myeloid cells has prompted us to investigate the nature of the most immature transduced hematopoietic precursor cells. Insertion sites shared by T and B lymphocytes as well as highly purified granulocytes and monocytes demonstrate the correction of common multipotent progenitor cells. Moreover, our data show that differentiated leukocytes share the same exact insertion sites with CD34+ cells that we obtained 8 months later and that were able to generate long-term culture-initiating cells (LTC-ICs). This finding demonstrates the initial transduction of very primitive multipotent progenitor cells with self-renewal capacity. These results provide a first evidence in the setting of a clinical trial that CD34+ cells maintain both lymphomyeloid potential as well as self-renewal capacity after ex vivo manipulation.

Antigens, CD34↗

PubMed2003

Comparison of three retroviral vector systems for transduction of nonobese diabetic/severe combined immunodeficiency mice repopulating human CD34+ cord blood cells.

The use of recombinant vectors based on wild-type viruses that are absent in humans and are not associated with any disease in their natural animal hosts or in accidentally infected humans would add an additional level of safety for human somatic gene therapy approaches. These criteria are fulfilled by foamy viruses (FVs), a family of complex retroviruses whose members are widely found among mammals and are apathogenic in all hosts. Here, we show by comparison of identically designed vector constructs that recombinant retroviral vectors based on FVs were as efficient as lentiviral vectors in transducing nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice repopulating human CD34(+) cord blood (CB) cells. The FV vector was able to achieve gene transfer levels up to 84% of engrafted human cells in a short overnight transduction protocol. In contrast, without prestimulation of the target cells, a human immunodeficiency virus type 1 (HIV-1)-based lentiviral vector pseudotyped with gibbon ape leukemia virus envelope (GALV Env) was nearly as inefficient as murine leukemia virus (MLV)-based oncoretroviral vectors in transducing NOD/SCID repopulating cells. The same HIV vector pseudotyped with the vesicular stomatitis virus glycoprotein G (VSV-G) achieved high marking efficiency. Clonality analysis of bone marrow samples showed oligoclonal hematopoiesis with single to multiple insertions per cell, both for FV and HIV vectors. These data demonstrate that vectors based on FVs warrant further investigation and development for medical use.

Animals↗

PubMed2003

Clonality analysis after retroviral-mediated gene transfer to CD34+ cells from the cord blood of ADA-deficient SCID neonates.

A clinical trial of retroviral-mediated transfer of the adenosine deaminase (ADA) gene into umbilical cord blood CD34(+) cells was started in 1993. ADA-containing peripheral blood mononuclear cells (PBMCs) have persisted in patients from this trial, with T lymphocytes showing the highest prevalence of gene marking. To gain a greater understanding of the nature and number of the transduced cells that were engrafted, we used linear amplification-mediated PCR (LAM-PCR) to identify clonal vector proviral integrants. In one patient, a single vector integrant was predominant in T lymphocytes at a stable level over most of the eight-year time span analyzed and was also detected in some myeloid samples. T-cell clones with the predominant integrant, isolated after eight years, showed multiple patterns of T-cell receptor (TCR) gene rearrangement, indicating that a single pre-thymic stem or progenitor cell served as the source of the majority of the gene-marked cells over an extended period of time. It is important to distinguish the stable pattern of monoclonal gene marking that we observed here from the progressive increase of a T-cell clone with monoclonal gene marking that results from leukemic transformation, as observed in two subjects in a clinical trial of gene therapy for X-linked severe combined immunodeficiency (SCID).

Adenosine Deaminase↗

PubMed2003

Efficient characterization of retro-, lenti-, and foamyvector-transduced cell populations by high-accuracy insertion site sequencing.

The identification of unknown genomic flanking DNA sequences can be used for the molecular monitoring of retro-, lenti- and foamyviral integration, transgenes in early embryogenesis, insertional mutagenesis, cell fate, and stem cell plasticity. Most existing methods reflect shortcomings in sensitivity and or specificity, thus limiting genomic sequencing of unknown flanking DNA to clonal preparations. The application of linear amplification-mediated PCR (LAM-PCR), a recently developed direct sequencing technique for flanking DNA, should circumvent current limitations in different research fields. This technique combines preamplification of target DNA with a unique succession of enzymatic reactions on solid-phase. Using LAM-PCR, we show the previously unfeasible in vivo retro-, lenti- and foamyvirus integration site analysis in primate peripheral blood hematopoietic cells and human xenograft hematopoiesis. In light of two severe adverse events that occurred in a clinical SCID-X1 gene therapy trial, in vivo monitoring of the reinfused transduced cell pool by integration site analysis will be an important component of each gene transfer and therapy study aimed at clinical use.

Animals↗

PubMed2002

Polyclonal long-term repopulating stem cell clones in a primate model.

Hematopoietic bone marrow stem cells generate differentiated blood cells and, when transplanted, may contribute to other organs, such as the brain, heart, and liver. An understanding of in vivo clonal behavior of stem cells will have important implications for cellular and gene therapy. For the first time, we have directly demonstrated the derivation of circulating peripheral blood cells from individual stem cell clones. We analyzed the clonal composition of retrovirus-marked peripheral blood leukocyte populations in 2 different primate models by a novel direct genomic sequencing technique allowing the identification of vector insertion sites. More than 80 contributing long-term hematopoietic clones were identified in individual rhesus macaque peripheral blood transplant recipients and more than 25 different clones in a baboon marrow transplant recipient. Up to 5 insertion sequences from each animal were used to trace the long-term contribution of stem cell clones in these primate models. Continuous and mostly pluripotent contributions of peripheral blood leukocytes from each of the traced clones could be detected for the entire follow-up period of 23 to 33 months. Our study provides direct molecular evidence for a polyclonal, multilineage, and sustained contribution of individual stem cells to primate hematopoiesis.

Animals↗