MAYP is expressed in macrophages and a subset of granulocytes in mice and humans. (A-D) Immunofluorescence staining of mouse peripheral blood leukocytes FACS-sorted based on Mac1 and Gr1 and cytocentrifuged onto fibronectin-coated coverslips, fixed, permeabilized, and stained with DAPI and anti-MAYP antibody, showing the pattern of MAYP staining in Mac1^hiGr1^lo monocytes (A), Mac1^loGr1^hi granulocytes (B), Mac1^hiGr1^hi monocytes or monocyte precursors (C), and Mac1^loGr1^lo lymphocytes (D). Note diffuse staining of MAYP in panel B and its exclusively nuclear staining in panel D compared with the punctate cytoplasmic staining characteristic of MAYP in panels A and C. Panels on the right represent merged signals of Mac-1 (blue), MAYP (green), and Gr1 (red). (E) SDS-PAGE and Western blot analysis of MAYP expression in mouse BMMs, granulocytes (Gr), and the Mac1^hiGr1^hi fraction. (F) Western blot analysis of MAYP expression in lymphocyte (Ly; nonadherent peripheral blood mononuclear cells), monocyte (Mo; adherent peripheral blood mononuclear cells), and granulocyte (Gr) fractions of human peripheral blood. (E-F) Single and double asterisks indicate positions of cross-reactive protein bands. (G-I) Immunofluorescence staining of fractions from panel F. Ly fraction (G-H), showing contaminating MAYP+ monocytes, and Gr fraction (I) showing MAYP staining of a Mac1+ subfraction of the granulocytes (10% of total). Bars, 10 μm.