FIG. 6.

Differential histopathologies in the livers of mice. Sections of infected (A to D, F to G, and I to J) and uninfected (E, H, and K) livers were stained by IHC using Y. pestis-specific antibody (A and B) or by H&E (C to K). Wild-type (C, F, and I) and Δcaf1M1A1 (D, G, and J) bacteria stained brown by IHC (A and B) and blue by H&E (C, D, F, G, I, and J) were widely dispersed in the infected tissue, but the Δcaf1M1A1 mutant tended to form larger and more numerous colonies. The green arrowheads indicate examples of bacteria. Magnification, ×40 (A to E), ×100 (F to H), and ×400 (I to K).