TGF-β expression in spleen section from mice engrafted with WT or TGF-β1^−/−virus–infected hematopoietic cells.

Immunocytochemistry using a TGF-β–specific antibody (A,B). Immunostaining specificity was checked by omitting the primary antibody (C,D). Representative sections are shown at 3 months after transplantation. (A) Mouse engrafted with WT cells showing strong positivity in MK and granulocytes. (B) Mouse engrafted with TGF-β1^−/− cells showing no immunoreactivity. (C,D) No immunostaining was revealed when the primary antibody was omitted. Original magnification, × 600 for all panels.