LONG-TERM HUMAN PERIPHERAL-BLOOD MONOCYTE CULTURES - ESTABLISHMENT, METABOLISM AND MORPHOLOGY OF PRIMARY HUMAN MONOCYTE-MACROPHAGE CELL-CULTURES

Abstract

Human peripheral blood monocytes were maintained in in vitro culture up to 4 mo. using a non-human serum source. Monocytes were cultured in Dulbecco''s modified Eagle''s medium buffered with 20 mM HEPES [4-(2-hydroxyethyl)-1-piperazine-N''-2-ethanesulfonic acid] and containing 10% horse serum and 10% fetal calf serum. Metabolic and morphological changes occurring in vitro were investigated using microtitre, Linbro and T 25 cultures. During culture, monocytes increased in size, had increased membrane activity as visualized by SEM [scanning electron microscopy], and differentiated into a morphologically heterogeneous population of fusiform and epithelioid shapes. These cell types retained the ability to phagocytose E glut [glutaraldehyde treated erythrocytes] and EA [antibody-coated erythrocytes] and to rosette with EA and EAC [EA-complement]. Larger giant polynucleated cells were also observed during culture; many lacked the ability to bind or phagocytose inert erythrocytes or EA. Increases in lysozyme release and acid phosphatase activity also occurred during culture. Cultured monocytes exhibited characteristic profiles of leucine and uridine uptake with maximal activity observed by 5 days of culture. There was no detectable thymidine uptake. Detailed analysis of regulatory processes involved in monocyte growth and differentiation could be performed with this in vitro system.