ImmunoMethods最新文献

The ability to culture and expand hematopoietic progenitor cells ex vivo has major implications for both bone marrow and stem cell support following marrow ablative or subablative high-dose therapy and for improving the efficiency of retroviral transfection in gene marking and gene therapy. This review focuses on methods for the generation of myeloid progenitor and post-progenitor cells from peripheral blood stem cell collections, with particular emphasis on the characterization of these cells and practical issues associated with their expansion.

There is increasing evidence that the presence of tumor cells within autologous hematopoietic cell grafts may increase the risk of relapse of disease post-transplant. The sensitive detection of minimal residual disease is therefore central to improving the outcome of autologous transplantation, irrespective of the source of the graft. This review presents a comparative evaluation of the sensitivity and specificity of the currently available methods for tumor detection.

In the 5 years since the first human gene therapy studies began, more than 70 clinical protocols have been approved, and over 200 patients have received genetically modified cells. A high proportion of these protocols have made use of hematopoietic progenitor cells or their mature progeny. In this review, we discuss the progress and limitations of current clinical gene transfer studies using marrow-derived progenitor cells and describe how the technique is being applied to the treatment of single-gene disorders and to augment cancer immunotherapies. We also discuss the contribution made by gene marking studies.

It has been demonstrated that it is possible to mobilize hematopoietic progenitor cells from the bone marrow into the peripheral blood, from which they can be collected by apheresis and used for transplantation. Although the clinical results obtained using this approach have not been compared in a randomized trial to those obtained using bone marrow, it appears that this method has certain advantages. These, together with future developments, are discussed in this review.

Graft-vs-host disease (GVHD) in allogeneic hematopoietic transplantation can be abrogated by T-cell depletion (TCD) of the graft. Researchers have sought the optimal TCD procedure, which would alter the activity, number, and/or subpopulation profile of T cells to acceptable levels, while retaining sufficient engraftment potential of the harvested hematopoietic stem cells. The techniques that have successfully survived the translation from research studies into practical clinical application may be analyzed by their effectiveness, efficiency, ease of application, and cost. The predominant techniques rely on either physical separation of the T cell (binding to erythrocytes, lectins, centrifugation) or reaction with monoclonal antibodies (immunomagnetic, panning, complement-mediated cytotoxicity, immunotoxins). Comparative trials between the various techniques are few, making comparisons difficult. However, all of the techniques, whatever their relative advantages and disadvantages, must meet the same challenges.

There is currently renewed interest in the potential of tumor cells within autologous hematopoietic grafts to contribute to relapse of cancer post-transplant. This has prompted the development of a wide variety of techniques for the ex vivo removal or purging of malignant cells from bone marrow and peripheral blood progenitor cell grafts. Both negative selection, in which tumor cells are eliminated, and positive selection, in which hematopoietic stem cells are enriched, are under examination as purging modalities. This review describes the use of immunologically based methods for autologous graft engineering.

Even though there has been considerable progress in the phenotypic characterization of CD34⁺ bone marrow cells, there is still limited knowledge about the cell phenotypes corresponding to functional terms such as colony-forming cells, burst-forming cells, long-term culture-initiating cells, and high-proliferative potential cells. In this study, we performed a detailed analysis of phenotypic characteristics of subsets of CD34⁺ cells. We compared cells from adult and fetal bone marrow to investigate whether reported functional differences are reflected in the cellular phenotypes. CD34⁺, CD38^−/lo, HLA-DR⁺ cells, which have been shown to contain the most immature hematopoietic progenitor cells, stained as a homogeneous population with most monoclonal antibodies (mAbs). The antigens sLe^x, CD32, and CD7 were, however, heterogeneously expressed in the CD38^−/lo population. Phenotypic differences in the CD34⁺, CD38^−/lo population was found when comparing adult and fetal bone marrow cells. Adult bone marrow CD34⁺, CD38^−/lo cells stained more brightly with CD4, Thy-1, and CD49b and more dimly with CD32 than the same population in fetal bone marrow. Certain antigens that have previously been regarded as lineage-specific were found on the CD34⁺, CD38^−/lo, HLA-DR⁺ cells in both fetal and adult bone marrow. These included CD52, CD13, and CD33. The markers that were found to be most useful in discriminating between subsets of lineage-committed cells within the CD34⁺, CD38⁺ population included the B cell marker CD19 and the granulomonocytic marker CD64. The phenotypic analysis presented here should provide a basis for establishing a better link between functional and phenotypic characteristics of hematopoletic progenitor cells.