Serial sections of hamster lung tissue showing a high density of L. interrogans serovar Pomona strain 11000-74A within the lumen of a blood vessel. Tissue sections were stained with PAS/Steiner silver stain (B), or by immunohistochemistry using no primary antibody (A), LipL32 antiserum (C, E), or LipL46 antiserum (D, F). Magnification ×30 (B) and ×40 (A, C, D). (E, F) Enlargements of the boxed areas shown in (C) and (D), respectively. (B, E, F) Insets are enlargements of boxed areas in the same panels.