Purification of human monocytes by adherence to polymeric fluorocarbon. Characterization of the monocyte-enriched cell fraction.

Human mononuclear cells were obtained from peripheral blood by density gradients. Monocytes can be purified after cultivation of 2 hours by a modified adherence procedure on membranes of gas-permeable polymeric fluorocarbon (teflon). After further cultivation of 24-48 hours, monocyte-enriched cell fraction can be easily detached from the membranes with a viability greater than 98% and a final cell yield of approximately 50% of the peripheral monocyte count. The cells showed the morphological and cytochemical characteristics of human monocytes and differentiated into dense monolayers of macrophages within 10 days of cultivation. Immune-autoradiography with iodine-125-labelled xenogeneic antimonocytic antisera and staining with several monoclonal antisera in an indirect immunofluorescence technique revealed up to 92% of these cells to carry monocytic characteristics. To show their functional integrity, monocytes obtained by this procedure were activated by 48 hours' cultivation with synthetic alkyl-lysophospholipids to inhibit the proliferation of autologous tumor cells.