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1989
Journal Article
Titel
Effect of human recombinant IL-2 on murine macrophage precursors
Abstract
Homogenous populations of bone marrow derived murine macrophage precursors are able to respond to human rIL-2. A prolonged exposure to the lymphokine results in proliferation and in the final differentiation of macrophage precursors to mature macrophages, as shown by follow-up to the antigenic profile by means of cytofluorograph analysis. The frequency of the IL-2 responding cells was 1/48 as determined by limiting dilution analysis, and no cell death was evidenced in soft agar cultures. An analysis of the IL-2-binding sites conducted on bone marrow derived macrophage precursors revealed the presence of 4000 binding sites with intermediate affinity. Bone marrow-derived macrophage precursors did not react, even after prolonged culture in IL-2-conditioned media, with mAb recognizing the binding site or a binding site-associate molecule of a Mr 50000 to 60000 component of the IL-2R expressed by the IL-2-dependent T cell line CTLL-2. Crosslinking studies showed the presence of a single bin ding protein, with an apparent Mr of 70000. Macrophage precursors also proved able to internalize human rIL-2 within the first 20 minutes of incubation at 37 degree C. The implications of these findings are discussed.