CELLULAR INTERACTIONS IN HEMATOPOIETIC PROGENITOR-CELL HOMING - A REVIEW

Within the bone marrow microenvironment, dynamic cellular interactions are constantly occurring. These interactions involve hemopoietic stem cells, progenitor cells and maturing cells, physically interacting wi th other cells, some of which may function as accessory cells, and oth ers which comprise the stromal elements; hemopoietic cells also intera ct with non-cellular elements, such as glycoproteins and fibrous prote ins of the extracellular matrix (ECM). These interactions serve to reg ulate normal hemopoiesis by allowing the communication of regulatory i nformation, migration and subsequent homing of stem cells within speci fic organs, and presentation of hemopoietic growth factors in a biolog ically relevant fashion. The goal of this review is to examine the spe cific cellular interactions that relate to the phenomenon of homing of intravenously transplanted stem cells to the bone marrow.