Abstract
Investigations of the activation processes involved in human monocytes and monocyte-derived macrophages and dendritic cells often required large numbers of cells that have not been possibly altered or activated by adherence to surfaces, by binding of antibodies to surface antigens during positive selection, or by release of activators by platelets or other non myeloid cells during isolation or co-culture. Human peripheral blood monocytes as well as lymphocytes from the same blood donor can be isolated by counterflow elutriation using a modification of the technique of Lionetti et al., 1980 as described previously (Bobak et al., 1986). From a unit of blood drawn into anticoagulant, 60-120 million monocytes can be obtained. These cells are not activated and have been shown to be appropriately capable of differential activation in multiple studies.