Granulocyte‐macrophage colony‐stimulating factor‐cultured bone marrow‐derived macrophages reveal accessory cell function and synthesis of MHC class II determinants in the absence of external stimuli

摘要

AbstractThe antigen‐mediated activation of a number of T cell clones by bone marrow (BM) cells cultivated in the presence of various colony‐stimulating factor (CSF) preparations was investigated. BM macrophages (BMMϕ,) grown in L929 cell supernatant as a crude source of macrophage colony‐stimulating factor (M‐CSF) as well as BM cells propagated in the presence of recombinant M‐CSF exhibited transient antigen presentation potential to some T cell clones, being maximal on day 7 and having declined to a low level by day 19 ofin vitroculture. Treatment of these long‐term‐cultivated BMMϕ, populations with recombinant interferon‐γ (IFN‐γ) resulted in predominant antigen presentation capacity. In contrast, BM cells differentiated in the presence of recombinant granulocyte (G)M‐CSF developed highly efficient accessory cell function to all T cell clones examined. This function became apparent earlier, was retained during the time period tested (up to day 19 of continuous culture) and did not require prior stimulation by IFN‐γ. The functionally competent cells were shown to belong to the monocyte/macrophage lineage. These findings are consistent with the demonstration of substantial levels of major histocompatibility complex (MHC) class II molecules synthesized by GM‐CSF‐cultured BM cells in the absence of exogenous IFN‐γ. In contrast, M‐CSF grown BM cells synthesized only minute amounts of Ia antigens unless they were stimulated by IFN‐γ. Because GM‐CSF‐cultivated BM cells proved clearly superior to M‐CSF‐grown and IFN‐γ‐activated BM cells with respect to antigen‐presenting capacity but exhibited lower levels of MHC class II molecules, other properties acting in addition to surface Ia antigens might be respo