Asymptomatic Cattle Naturally Infected with Mycobacterium bovis Present Exacerbated Tissue Pathology and Bacterial Dissemination
Figure 5
Histopathological analysis of cellular profile of granulomatous response in lung of asymptomatic cattle naturally infected with M. bovis.
(A) Lung tissues were categorized according to the granuloma cellular response profile and tissue remodeling into four groups: I-IV. Representative lung-tuberculous granulomatous response patterns are shown: I (1 and 2) encapsulated granulomas with caseous necrosis areas and presence of several scattered lymphocytes and dense clusters of neutrophils near the capsule; II (3 and 4) encapsulated granuloma, with extensive areas of caseous necrosis. Granulomatous cellular response composed primarily of epithelioid macrophages, lymphocytes, multinucleated Langhańs giant cells and clusters of neutrophils; III (5 and 6) encapsulated granulomas, with extensive multicentric areas of caseous necrosis and centralized dystrophic mineralization. Granulomatous cellular response composed of epithelioid macrophages and scattered Langhan’s giant cells, which surround the necrotic areas with dense clusters of lymphocytes and few neutrophils; III (7 and 8) encapsulated granulomas, with extensive multicentric areas of caseous necrosis and centralized dystrophic mineralization. Granulomatous cellular response composed of epithelioid macrophages admixed with increased numbers of multinucleated Langhan’s giant cells, dense clusters lymphocytes and few neutrophils. Left panels, slides shown at 10× magnification; Scale bar = 100 µm. Right panels, slides shown at 40× magnification; Scale bar = 50 µm. (B) Results presented are mean ± SEM for each group shown in (A). Correlation between neutrophil counts and histopathology grades (C), Correlation between viable mycobacterial loads and neutrophils (D), multinucleated Langhańs giant cells counts (E) as well as lung-granulomatous response profile (F). Spearman’s correlation indexes (Spearman’s r and p values) are shown in the graphs (n = 168 animals for correlation figures).