Course of cutaneous leishmaniasis in B6.Ceacam1^−/− and B6.WT mice and characterization of local lymphatic and blood vessel formation. (A) Footpad swelling after infection with Leishmania major. Weekly recordings of footpad swelling are shown for B6.Ceacam1^−/− (○) and B6.WT mice (■). Footpad swelling is expressed as the percentage of increase of the infected over the noninfected footpad, respectively. Data shown here summarize the mean (± SEM) from 6 animals each; the experiment was repeated 3 times. *P < .05, **P < .01. Photographs of footpads from a B6.WT (B) and a B6.Ceacam1^−/− mouse (C) document ulcerations (indicated with ) in the B6.Ceacam1^−/− animal on day 41 after infection. (D-G) Representative histologic analyses of cross-sections of the infected footpads of B6.WT (D,F) and B6.Ceacam1^−/− mice day 21 after infection (E,G). Cryostat sections were analyzed by H&E staining (D,E) and immune fluorescent labeling (F,G) of lymphatic vessels (anti–LYVE-1 antibody; shown in red), blood vessels (anti–Meca-32 antibody; shown in green), and nuclei (DAPI; shown in blue). The dotted white line indicates the borderline between skin and inflammatory infiltrate. Magnification × 200. (H-J) Quantification of edematous areas and lymph and blood vessel formation in cross-sections of infected footpads of B6.WT (■) and B6.Ceacam1^−/− mice (□). Data shown here represent mean (± SEM) from at least 6 specimens. (H) Cell-free areas were determined by quantifying the DAPI-free areas, expressed relative to the total inflammatory area analyzed; ***P < .001. (I) Quantification of lymphatic vessels by calculating the percentage of LYVE-1⁺ areas in cross-sections of infected footpads; ***P < .001. (J) Quantification of MECA-32⁺ areas relative to the total areas analyzed and expressed as the percentage of MECA-32⁺ areas, **P < .01.