Eosinophils from lineage-ablated Delta dblGATA bone marrow progenitors: the dblGATA enhancer in the promoter of GATA-1 is not essential for differentiation ex vivo.

A critical role for eosinophils in remodeling of allergic airways was observed in vivo upon disruption of the dblGATA enhancer that regulates expression of GATA-1, which resulted in an eosinophil-deficient phenotype in the DeltadblGATA mouse. We demonstrate here that bone marrow progenitors isolated from DeltadblGATA mice can differentiate into mature eosinophils when subjected to cytokine stimulation ex vivo. Cultured DeltadblGATA eosinophils contain cytoplasmic granules with immunoreactive major basic protein and they express surface Siglec F and transcripts encoding major basic protein, eosinophil peroxidase, and GATA-1, -2, and -3 to an extent indistinguishable from cultured wild-type eosinophils.