Immunophenotype of mouse BLL. Shown are representative tissue sections of lymphomas after immunostaining with antibody to B220 (A), IgM (B), CD19 (C), and Bcl-6 (D), followed by horseradish peroxidase (HRP)–conjugated secondary antibody (1:200 dilution). The images were captured by a Zeiss Axiophot microscope equipped with a DC330E CCD camera (Dage MTI, Michigan City, IN) and Scion Image software (Scion, Frederick, MD). The original magnification of the objective lens was 40 ×, and its numerical aperture was 0.75. Scion Image software (Scion, Frederick, MD) was used to capture images.