GM-CSF Hypersensitivity of Bone Marrow Cells from Triple Transgenic Mice A.Western Blot of bone marrow cells stimulated with GM-CSF. Panel A shows time course after stimulation of bone marrow cells from conditional Cbl mice (Cbl^fl/fl) that have the endogenous Cbl gene deleted using the MMTV-Cre transgene. B-D.Quantitation of several blots showing GM-CSF hypersensitivity. When normalized to the nontransgenic mice at time point zero, there is increased activity of downstream signaling pathways with and without GM-CSF.