Plg-RKT expression by human monocytes. Membrane and cytoplasmic fractions of human peripheral blood monocytes (PBMs), U937 cells, THP-1 cells, and M-CSF–differentiated Hoxa9-ER4 cells (30 μg/lane; A) and lysates of human granulocytes, lymphocytes, RBCs, and M-CSF–differentiated Hoxa9-ER4 cells (40 μg/lane; B) were electrophoresed on 4%-20% SDS gels under reducing conditions and Western blotted with anti–Plg-RKT mAb 7H1. The blots were stripped and reprobed with anti–α-enolase mAb 9C12 (A,B) as a loading control. No immunoreactive bands were detected with isotype control (data not shown).