Characterization of the adherence of normal and leukemic CD34+ cells to endothelial monolayers.

The capacity of normal CD34+ marrow cells and CD34+ leukemic cell lines to adhere to human umbilical vein endothelial cells has been examined. Such interactions have importance since the processes of homing and egress within the marrow microenvironment involve the traverse of sinusoidal endothelium. Umbilical vein endothelial monolayers expressed CD44 and CD54 constitutively, and expression of both E-selectin (ELAM) and vascular cell adhesion molecule-1 (VCAM-1) were inducible with interleukin-1 (IL-1) alpha and beta and tumor necrosis factor (TNF).

Expression of integrins and examination of their adhesive function in normal and leukemic hematopoietic cells.

Adhesion of hematopoietic progenitor cells to marrow-derived adherent cells has been noted for erythroid, myeloid, and lymphoid precursors. In this report, we have characterized very late antigen (VLA) integrin expression on normal CD34+ marrow progenitors, on leukemic cell lines, and on blasts from patients with acute myelogenous or monocytic leukemias. CD34+ progenitor cells expressed the integrin beta 1 chain (CD29), VLA-4 alpha (CD49d), and VLA-5 alpha (CD49e).

Cytokine effects and role of adhesive proteins and Fc receptors in human macrophage-mediated antibody dependent cellular cytotoxicity.

Mononuclear phagocytes participate in host immunological defense against tumors. We have investigated the role of selected recombinant cytokines on human macrophage-mediated tumor cytotoxicity in vitro utilizing a human colon cancer cell line target, SW1116, and murine monoclonal antibody 17-1A. Blood monocytes were kept in continuous culture to allow differentiation into macrophages.