ADHESIVE INTERACTIONS IN HEMATOPOIESIS

Blood cells developing in the bone marrow exhibit adhesive interaction s with stromal reticular cells and specialized macrophages, and with s everal defined components of the extracellular matrix, Receptors that are known to participate in these interactions include certain integri ns, selectins, members of the immunoglobulin superfamily, and CD44, an d this list may be expected to grow. Specific inhibitors of some integ rins and of CD44 have been shown to disrupt hemopoiesis in vitro, thus the function of adhesive receptors appears critical to blood cell dev elopment. The capacity of such receptors to transmit signals through t he plasma membrane suggests that they regulate not just the physical i nteractions of hemopoietic cells, but also the responses of the cells to their environment.