Colocalization of cross-linked fibrin and neo in TM^−/− chimeric mouse lung. PLP-fixed cryosections of mouse lung were stained with anti-neo antibody and acid-washed serial sections stained with the anti-fibrin/fibrinogen antibody before counterstaining with hematoxylin. Shown is a representative image from a high-percentage chimeric mouse in the 15- to 20-month age group. Low-power views of serial cross sections show that neo (a) is present in the same blood vessels that demonstrate immunoreactivity for cross-linked fibrin (XL-Fibrin, b). Higher power magnification, c and d, of the same images as shown in a and b. Arrows indicate blood vessels. Original magnification in panels a and b, × 50; panels c and d, × 125.