Abstract
By using a helper-free and replication-defective recombinant retrovirus encoding the SV40 early antigens (MV40), we have established continuous macrophage (Mφ) lines. All of the lines were nonproducer M φ's with differentiated Mφ functions such as phagocytosis, cytotoxicity, and IL-1 and TNF production. To determine the effects of several cytokines on growth of mature Mφ's, the responsiveness of these established Mφ lines to various cytokines was investigated in methylcellulose culture. Their response patterns to several cytokines alone and in combination were different, implying that there might be mature Mφ subpopulations with distinct growth profiles regulated by several cytokines. On the other hand, all of the lines efficiently yielded a number of colonies in response to interleukin-4 (IL-4) alone. Moreover, IL-4 cooperated with interleukin-3 (IL-3) to enhance colony formation of all the lines. A similarly synergistic effect was observed in combination of IL-4 and macrophage-colony stimulating factor (M-CSF) in almost all the lines. Similar results were obtained with colony formation of fresh thioglycolate-induced Mφ's. These observations suggested that IL-4 was involved in growth of mature Mφ's.
Our present results suggest that the helper-free and replication-defective MV40 is of use to obtain continuous and functional cell lines from primary Mφ's.
