Colocalization of laminin chains in arteriolar walls and in megakaryocytes.

(A,B) The 2 micrographs show 2 consecutive bone marrow cryostat sections stained with the antilaminin α5 chain antibody, 4C7 (A), and the antilaminin β2 chain antibody, C4 (B). A colocalization of these 2 laminin chains in arteriolar walls cells could be observed. (C,D) By double labeling of a bone marrow cryostat section, a coexpression of the laminin α2 chain (C) and of α-SM actin (D) could also be found in arteriolar walls of larger blood vessels within the marrow. Outside arteriolar walls no laminin α2 chain expression could be detected. (E,F) Double immunofluorescence staining of a bone marrow cryostat section with the polyclonal antiserum against the LN-1 isoform (E) and an anti–β3 integrin chain antibody (F) revealed that megakaryocytes (arrows in E and F) do not express laminin β1 or γ1 chains. (Original magnification × 220.)