Fluorescence microscopy images of immunophenotyped lymphocytes of blood and lymph nodes from a healthy dog and dogs with lymphoma. Lymphocytes stained with anti-CD3+FITC (green color) and anti-CD21+PE (red color) antibodies and Hoechst nuclear stain (blue color), original magnification 40×. (A) Fused image (360 nm, 480 nm, 525 nm) of normal peripheral blood from a dog, predominance of (CD3+) T-lymphocytes. (B) B-cell lymphoma, lymph node aspirate (picture taken after excitement at 525 nm). All the cells seen are (CD21+) (C) T-cell lymphoma, lymph node aspirate (picture taken after excitement at 480 nm). All the cells seen are (CD3+) T-lymphocytes.