The Role of Cytokines in Hematolymphoid Development

摘要: For an uncommitted mesodermally derived stem cell to develop into a functionally mature blood cell, it must be capable of proliferation, commitment, differentiation, survival, and homing. These complex processes are tightly regulated by signals from the cells that make up microenvironment in which hematopoiesis takes place. include variety types, both nonhematopoietic fixed-tissue such as fibroblasts epithelial (collectively referred “stromal cells”), hematopoietic themselves. influence three major ways: providing through direct cell—cell contact, secreting components extra-cellular matrix (ECM), and, soluble factors. Together, these comprise inductive or HIM (1). Microenvironments within different tissues distinct specialized supporting development specific populations. example, thymus almost exclusively supports T-cell consists separate class cells, bone marrow-derived cytokines marrow, myeloid, erythroid, B-cells. The intriguing observation precursor thymus, when injected recipient mice (2), cultured vitro with marrow stromal (3), can give rise B-cells and/ macrophages, exemplifies nature microenvironments demonstrates ability sites support generation lineages.