Problems with the isolation of pure populations of dendritic cells (DC) have hindered investigations of their various functional attributes. Permanent cell lines have, however, been established from murine macrophages by means of novel recombinant retroviruses.1,2 A new ectropic retrovirus carrying the v-myc oncogene of the avian MH2 leukemia virus together with the LTRs of the mouse AKR virus, is capable of activating transcription and secretion of M-CSF and expression of M-CSF receptors. An autocrine loop is set up in infected macrophages.3,4 Recent developments in the induction of division and differentiation of murine DCs from either blood or bone marrow progenitors have provided an opportunity to establish permanent DC cell lines.5 Growth and division of DC precursors in culture on exposure to GM-CSF is dramatic and the pathway of differentiation appears to be titled away from the macrophage phenotype. The objective of this study was to expose developing murine bone marrowderived DC progenitors to the immortalizing retrovirus 3RV from the N-ll cell line.2 This was an attempt to create permanent DC cell lines which maintain both phenotypic and functional characteristics of the DC lineage.KeywordsDendritic CellBone Marrow ProgenitorContact HypersensitivityBone Marrow Progenitor CellPermanent Cell LineThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.