Figure 1.

Bacillary load, accumulation of activated PMN in Mtb-infected rabbit lungs. (A) Total lung bacillary load in Mtb HN878- or CDC1551-infected rabbits at 3 hours post-infection. The values plotted are mean ± standard deviation from four animals per group (B) Numbers of polymorphonuclear (PMN) cells in the lungs of Mtb HN878- or CDC1551-infected rabbits at 3 hours post-infection. The values plotted are mean ± standard deviation (C). Levels of myeloperoxidase (MPO) activity used to determine the activation status of PMNs. MPO activity was measured calorimetrically in the lung homogenates of Mtb HN878- or CDC1551-infected rabbits at 3 hours post-infection and reported as change in OD₄₆₀ / min / g protein. The values plotted are mean ± standard deviation from triplicate assays from 3 animals per group. (D and E) Representative lung section histology of Mtb HN878- (D) or CDC1551- (E) infected rabbits at 3 hour post-infection stained with H&E and photographed at 400x magnification. Arrows point to PMNs. These cells in the rabbit contain red granules when stained with H&E and are known as heterophils. The scale bar (50 μM) is same for (D) and (E).