The generation of human monocyte/macrophage cell lines

The development of continuous murine macrophage-like cell lines has permitted direct and somatic cell genetic approaches to a variety of functions of murine mononuclear phagocytes. However, few, if any, human cell lines exist that have the general characteristics of macrophages, although a promonocyte line, U937, has been reported which can be induced to differentiate into non-dividing cells with macrophage-like properties. Although murine macrophage-like lines have been obtained by transformation with simian virus 40 (SV40), this technique has not, in general, been useful in producing human cell lines, presumably because SV40 causes a lytic infection in human cells. We have therefore developed a method for transfecting primary human monocytes with SV40 DNA deleted in the origin of replication. Using this method, we have now, we believe for the first time, generated transformed human cell lines with macrophage characteristics. Three cell lines from three transfections of human monocytes expressed macrophage enzymes, phagocytic function, surface receptors including HLA-DR and DS and alloantigen presenting activity.