Effect of heparin on lymphopoiesis and myelopoiesis in LTBMCs. (A, left) WBM cells were seeded using lymphoid-supportive (solid line) or myeloid-supportive (dashed line) conditions as described in Experimental Procedures. Heparin (•; 50 μg/mL), chondroitin sulfate (▵; 50 μg/mL), or vehicle (○) was added weekly beginning at culture initiation. (Right) LTBMCs cultured under myeloid-permissive conditions for 5 weeks were switched (arrow) to lymphoid-permissive conditions. Heparin (50 μg/mL) or vehicle was added weekly throughout the entire assay. (B) LTBMCs maintained under lymphoid-supportive conditions were cultured in the absence (left) or presence (right) of 25 μg/mL heparin for 6 weeks. Original magnification × 100. (C) Lymphoid-permissive LTBMCs were established for 4 to 6 weeks in the absence of treatment and then treated weekly with 50 μg/mL heparin or vehicle. The data are presented relative to the number of lymphocytes recovered from flasks receiving vehicle alone and results from three independent experiments are shown.