Fig. 4.

Implication of stromal macrophage colony-stimulating factor (M-CSF) and CD40L in the production of CD1a⁺ cells from blood CD34⁺ cells cultured with splenic fibroblasts. (a) Percentage of CD1a⁺ cells recovered from the cell monolayer after treatment with indicated neutralizing antibodies for 3 weeks. In the case of transwell cultures, values represent the total percentage of adherent and non-adherent CD1a⁺ cells. (b) Photographic images of cellular aggregates (arrow, original magnification × 100) and surviving cell numbers in cultures of CD34⁺ cells with rhM-CSF (100 ng/ml), neutralizing anti-M-CSF (10 µg/ml) and non-reactive antibodies (10 µg/ml) for 3 weeks. (c) Constitutive expression of CD40L in living splenic fibroblasts analysed by flow cytometry. Results are representative of at least two independent experiments. The dark line histogram indicates antigen expression. The light line histogram represents staining with an isotype control antibody.